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XX. DICRANUM Hedwig, Spec. Musc. 126.
1801 * [Greek dicranon, pitchfork] Robert R. Ireland Plants in loose to dense tufts, yellowish
green to dark green, dull or shiny. Stems (0.5–)2–12(–18) cm, erect,
simple or forked, densely tomentose with white or reddish brown, smooth to
papillose rhizoids, these sometimes nearly lacking, rhizoids arising at bases
of branches (macronemata) and sometimes in rows scattered along stems
(micronemata). Leaves usually lanceolate, rarely ovate, proximal part concave,
rarely flat, distal subula keeled to tubulose, erect-appressed, erect-patent
or spreading, straight, weakly curled, crispate or cirrate when dry,
generally falcate-secund, less often straight, undulate, rugose or smooth,
margins plane to incurved or involute, entire to serrate in distal part,
entire proximally, apex acute to obtuse, tips sometimes deciduous, apparently
a means of asexual reproduction; laminae 1- or 2-stratose at margins or
sometimes near costa; costa single, ending before apex to excurrent, smooth
or toothed on abaxial surface, sometimes with 2–4 serrated ridges abaxially,
1–2 rows of guide cells, 2 well-developed stereid bands above and below,
sometimes slightly differentiated or lacking, extending to apex, or ending
before the apex, adaxial and (or) abaxial epidermal layers of cells
differentiated or undifferentiated, sometimes only a few cells in both layers
enlarged; laminal cell walls weakly to strongly bulging, or bulges lacking;
leaf cells pitted or nonpitted, smooth or sometimes abaxially, rarely
adaxially, mammillose, papillose or toothed by projecting cell ends, walls
often thickened; distal and median laminal cells short or long, quadrate,
rectangular or irregularly angled, proximal cells rectangular to linear, alar
cells inflated, 1- or 2-stratose, rarely more, generally orange to brown,
rarely poorly differentiated. Specialized asexual reproduction lacking
or as clusters of 1–6, deciduous, terete, flagelliform branchlets, borne in
axils of distal leaves. Sexual condition dioicous or
pseudomonoicous; male plants as large as female plants or dwarfed and
epiphytic on stem rhizoids of female plants; perigonial leaves ovate,
concave, short-acuminate; perichaetial leaves convolute-sheathing, abruptly
subulate or rarely interior leaves gradually acuminate. Seta
solitary or up to 6 per perichaetium, erect, twisted when dry, yellow, brown
or reddish, elongate, smooth. Capsule erect or inclined, straight
or arcuate, cylindric, smooth, striate or furrowed when dry, annulus of 1–3
rows of usually large, deciduous or persistent cells, sometimes indistinctly
differentiated; operculum long-rostrate, straight or arcuate; peristome
single, 16 teeth, split 1/3–1/2 their length into 2 or, rarely, 3 divisions,
vertically pitted-striolate proximally, papillose above, reddish brown. Spores
spheric, 12–30 µm, finely papillose. Calyptra fugacious, cucullate,
smooth, naked, covering most of capsule, Species ca. 140 (26 in the flora):
North America, Central America, South America, Europe, Asia, Africa, and
Australia. For this flora the segregate genus Orthodicranum is not recognized. Whether to recognize this genus or not has
been debated for years. W. Peterson
(1979) listed the following six characters that he considered important in
separating this segregate from Dicranum:
(1) capsules straight vs. capsules curved; (2) capsules smooth to slightly
wrinkled vs. capsules ribbed; (3) alar cells 1-stratose vs. alar cells
2-stratose; (4) peristome teeth relatively narrow (ca. 60 µm) vs. peristome
teeth relatively wide (70–95 µm or more); (5) specialized asexual
reproduction by broken leaf tips or flagellated branches common vs.
specialized asexual reproduction rare; (6) specialized habitat of rocks and
wood vs. habitat of wood or rock rare, usually on soil or humus. The species placed in Orthodicranum by him as well as by other bryologists are D. flagellare,
D. fulvum, D. montanum, D. tauricum and D. viride. Dicranum
fragilifolium is another species in
our flora that has been placed there by some bryologists (e.g., J. Podpera
1954). The problem with recognizing
the genus Orthodicranum is that some
of the members otherwise remaining in Dicranum
share one or more of the six character states Peterson outlined for the
segregate genus. Dicranum fragilifolium and D.
rhabdocarpa are two of the species
that commonly have some of the characters of Orthodicranum and some of those of Dicranum. Other species
in Dicranum less commonly have
characters of both genera. If for no
other reason but the sake of utility it is more practical at this time to
leave all the species in one genus so they can be keyed out together and
compared more readily. Perhaps when a
world monograph of the genus Dicranum
is done it will become more evident whether it is important to recognize Orthodicranum and perhaps even other
segregate genera. Leaf cross sections of the leaves employed
in this treatment are necessary to observe cell features of the costa and
laminal cells. The costa stereid and
guide cells, the adaxial and abaxial epidermal cells, the number of layers of
alar and laminal cells, and the bulges in the cell walls between the laminal
cells are all observable in cross section.
These characters are extremely important because they can reliably
differentiate many species of Dicranum. The leaf cross section characters are usually less variable and
less influenced by the environment than other gametophytic characters, such
as leaf habit, shape, margins and costa length characters, and are utilized
to a great extent since they are considered much more dependable in species
identification than some of the other characters in the genus. SELECTED REFERENCES Allen, B. 1998a. The genus Orthodicranum
(Musci: Dicranaceae) in Maine.
Evansia 15(1): 9–20. Allen, B.
1998b. The genus Dicranum
(Musci: Dicranaceae) in Maine. Evansia 15(2): 45–80. Bellolio-Trucco, G. and R. R.
Ireland. 1990. A taxonomic study of the moss genus Dicranum
(Dicranaceae) in Ontario and Quebec.
Canadian Journal of Botany 68(4): 867–909. Chien, G., D.H. Vitt and S. He. 1999. Dicranum.
Pp. 163–193. In G. Chien and M.R.
Crosby (Editors), Moss Flora of China, Vol. 1. Sphagnaceae-Leucobryaceae. Bejing, New York and St. Louis. Crum, H. A. and L. E. Anderson. 1981.
Mosses of Eastern North America.
Vol. 1. New York. Ireland,
R. R. 1971. Dicranum. In E.
Lawton, Moss Flora of the Pacific Northwest.
Pp. 72–81, pl. 29–33. The
Hattori Botanical Laboratory, Nichinan, Japan. Ireland, R. R.
1982. Moss Flora of the
Maritime Provinces. National Museums
of Canada , Nat. Mus. Nat. Sciences, Publs. in Botany, No. 13. Ottawa.
Nyholm, E. 1986. Illustrated flora of Nordic mosses. Fasc. I.
Fissidentaceae-Seligeriaceae.
Odense. Peterson, W. 1979.
A revision of the genera Dicranum and Orthodicranum
(Musci) in North America north of Mexico.
453 pp. Ph.D. thesis,
University of Alberta, Edmonton.
Williams, R. S. 1913. Dicranaceae. N. Amer. Flora 15(2):
77–166. 1. Leaves mostly straight, erect-spreading,
the tips deciduous and lacking. 2. Costa
lacking stereid bands, with 1–2 layers of cells above and below the guide
cells in the basal part of leaf; alar cells 1-stratose; capsule straight,
erect; w North America.......................... 2. Costa
with stereid bands, although sometimes weak, with 2–3 layers of cells above
and below the guide cells in the basal part of leaf; alar cells 1- or
2-stratose; capsule straight and erect or arcuate; w or more often e North
America. 3. Leaves
shiny, with proximal cells pitted, distal cells rectangular, alar cells
2-stratose or with a few 1-stratose regions, lamina rarely with 2-stratose
regions......................................... 3. Leaves
dull, with proximal cells not pitted (or with few pits), distal cells
quadrate, alar cells 1-stratose or with few 2-stratose regions, lamina often
with 2-stratose regions................ 23. Dicranum viride 1. Leaves rarely straight, usually crisped
or falcate, the tips mostly present. 4. Distal
leaf cells usually elongate, sinuose, pitted. 5. Costa
with 2 rows of guide cells, without abaxial ridges; leaves 10–15 mm; setae often
aggregate......................................................................................................... 6. Dicranum majus 5. Costa with 1 row of guide cells, often
with abaxial ridges; leaves often less than 10 mm; setae solitary or
aggregate. 6. Leaves keeled distally, margins strongly
serrate to toothed in distal 1/2; costa with 2–4 well-developed dentate
ridges on abaxial surface in distal part of leaf. 7. Leaves
spreading, strongly undulate; setae aggregate, 3–5 per perichaetium..... 1. Dicranum polysetum 7. Leaves falcate-secund, not or slightly
undulate; setae solitary, rarely 2 per perichaetium. 8. Interior
perichaetial leaves gradually acuminate; endemic to w NorthAmerica.............................................................................................. 3. Dicranum howellii 8. Interior
perichaetial leaves abruptly acuminate; throughout most of North America........................................................................... 2. Dicranum scoparium 6. Leaves tubulose to somewhat keeled
distally, margins entire to serrate in distal 1/2; costa without or with
poorly developed dentate ridges distally on abaxial surface. 9. Costa subpercurrent to percurrent; alar
cells usually 1-stratose, rarely 2-stratose inpart; capsule slightly arcuate
to straight and erect. 10. Leaves
spreading to slightly falcate-secund, margins serrate near apex; capsule 2–4
mm; endemic to w North America. 7. Dicranum rhabdocarpum 10. Leaves
erect-spreading to erect-appressed, margins entire; capsule 1.5–2 mm; across
n North America............................. 20. Dicranum groenlandicum 9. Costa subpercurrent to excurrent; alar
cells 2-stratose; capsule slightly to strongly arcuate. 11. Leaves
with a long, narrow subula, apex acute to somewhat obtuse............... 11. Leaves with a short subula, apex obtuse to
somewhat acute. 12. Leaves
usually with twisted apex when dry; portion of some stemsjulaceous and
composed of short, broad, concave, appressed, somewhat obtuse leaves;
proximal leaf margins ± involute......................................... 5. Dicranum leioneuron 12. Leaves
seldom or never with twisted apex when dry; without julaceous portions of
stems; proximal leaf margins flat. 13. Leaves
rugose-undulate, shiny, cells smooth on abaxial surface................... 4. Dicranum bonjeanii 13. Leaves
not or little rugose-undulate, dull, cells often somewhat rough on abaxial
surface.................................................... 2. Dicranum scoparium (form) 4. Distal
leaf cells usually short (quadrate, rectangular, or irregularly angled),
neither sinuose nor pitted (or with few pits). 14. Proximal
leaf cells not pitted (or with few pits); alar cells usually 1-stratose,
rarely 2-stratose; capsule generally straight; plants averaging 2–4 cm. 15. Leaf
lamina mostly 2-stratose above, costa usually more than 1/4 width of leaf
base; usually on rock, rarely on corticolous substrates......................... 22. Dicranum fulvum 15. Leaf
lamina 1-stratose above, costa less than 1/4 width of leaf base; common on
wood and humus, sometimes on soil or rock. 16. Plants
with 2–6 flagelliform branchlets (rigid and terete branches with appressed
leaves) in the distal leaf axils; brood branches lacking; leaves tubulose
distally and slightly papillose on abaxial surface, curled to crisped when
dry; distal leaf cells short-rectangular to quadrate.................................... 26. Dicranum flagellare 16. Plants
lacking flagelliform branchlets; usually with weak, slender, broodbranches
with linear, strongly crisped leaves when dry; leaves semi-keeled distally
and strongly papillose on abaxial surface, generally strongly cirrate when
dry; distal leaf cells regularly quadrate............................................... 25. Dicranum montanum 14. Proximal
leaf cells pitted; alar cells 1- or often 2-stratose; capsule generally
arcuate; plants averaging 3–8 cm. 17. Leaves
tubulose in distal 1/2; costa often indistinct and scarcely prominent on
abaxial surface. 18. Leaf
cells strongly papillose in distal 1/2 of leaf; costa without stereids in
distal 1/4–1/3 of leaf, adaxial and abaxial epidermal layer of cells not or
scarcely differentiated; capsule sometimes strumose, 1–3 per perichaetium;
endemic to nw North America............................................................ 16. Dicranum pallidisetum 18. Leaf
cells smooth or weakly papillose in distal 1/2 of leaf; costa with stereid
bands in distal part of leaf as well as proximally, adaxial and abaxial
epidermal layer of cells sometimes differentiated; capsule not strumose,
solitary; across North America. 19. Leaves
cirrate to crisped when dry; distal leaf cells short-rectangular to quadrate,
with thin walls, proximal cells 9–12 ìm wide; costa with adaxial epidermal
layer of cells enlarged (seen in cross section near leaf middle); capsule 2–4
mm.................................................... 18. Dicranum muehlenbeckii 19. Leaves
erect-appressed or slightly curled when dry; distal leaf cells elliptic to
rectangular, with thick walls, proximal cells 5–6 µm wide; costa with only a
few cells in adaxial epidermal layer enlarged; capsule 1–2 mm. 20. Proximal
leaves with acute apices; proximal leaf cells usually less than 40 μm, median
cells pitted mainly proximal to middle of leaf.................. 19.
Dicranum elongatum 20. Proximal
leaves often with blunt apices; proximal leaf cells usually morethan 40 µm,
median cells pitted well distal above middle of leaf.. 20. Dicranum
groenlandicum 17. Leaves
keeled in distal 1/2; costa prominent and rounded on abaxial surface. 21. Leaves
plane or indistinctly undulate near apex. 22. Leaves
strongly cirrate to crisped when dry, proximal cells usually less than 45 µm;
capsule 3–4 mm............................................. 13. Dicranum brevifolium 22. Leaves
straight to ± curled when dry, proximal cells usually more than 45 µm;
capsule 1–3 mm. 23. Leaves
with distal margins ± involute, laminae with few 2-stratoseregions on margins
in distal part; leaf cells smooth to slightly papillose on abaxial surface in
distal part of leaf 14. Dicranum acutifolium 23. Leaves
with distal margins erect, laminae with one or both distal margins
2-stratose; leaf cells papillose on abaxial surface in distal part of leaf..................................................................... 15. Dicranum fuscescens 21. Leaves
undulate or rugose (Dicranum condensatum indistinctly undulate). 24. Costa
ending well before apex, rarely nearly percurrent 8. Dicranum undulatum 24. Costa
percurrent to excurrent. 25. Leaves
erect-spreading to erect and compressed when moist; distal-median leaf cells
irregularly angled, with unequally thickened walls; capsule 1.5–2 mm,
slightly contracted below mouth. 26. Leaves
gradually narrowed to a long-acuminate apex; costa with a few differentiated
cells in adaxial epidermal layer, cell walls between lamina cells not
bulging; nw North America......................................... 26. Leaves
acute to gradually narrowed to a short-acuminate apex; costa lacking
differentiated cells in adaxial epidermal layer, cell wallsbetween lamina
cells weakly to strongly bulging; e North America. 27. Leaves
ovate to ovate-lanceolate, concave and arched, loosely imbricate when dry.................... 12. Dicranum spurium 27. Leaves
broadly lanceolate, not arched, slightly crisped when dry, not imbricate............................ 11. Dicranum condensatum 25. Leaves
falcate-secund when moist; distal-median leaf cells short- rectangular to
quadrate, with equally thickened walls; capsule 2–4 mm, not contracted below
mouth. 28. Leaf
margins strongly toothed distally, laminae with tooth-like projections
scattered distally on abaxial surface; setae often aggregate, 1–5 per
perichaetium; capsule not strumose.................. 9. Dicranum ontariense 28. Leaf
margins slightly serrate distally, laminae smooth to slightly rough distally
on abaxial surface; seta always solitary; capsule ± strumose. 29. Leaves
strongly crisped to cirrate when dry, proximal leaf cells usually less than
45 µm; stems densely tomentose................ 13. Dicranum brevifolium 29. Leaves
straight to curled when dry, proximal leaf cells often more than 45 µm; stems
somewhat tomentose 14. Dicranum acutifolium 1. Dicranum
polysetum Swartz, Monthl. Rev. 34: 538. 1801 Dicranum rugosum (Funck) Bridel Plants in loose tufts, light green,
glossy. Stems 4–15 cm, densely tomentose with whitish or reddish
rhizoids. Leaves erect to spreading, ± flexuose, little changed when dry,
strongly undulate, (5.5–)7–9.5(–10.5) × 1–2 mm, lanceolate, concave
proximally, keeled above, acute, margins strongly toothed in distal 1/2;
laminae 1-stratose; costa ending before apex, occupying ca. 1/16–1/8 of leaf
base, strong, with 2 toothed ridges distally on abaxial surface, with 1 row
of guide cells, 2 stereid bands, adaxial epidermal layer of cells not
differentiated, abaxial layer with a few cells enlarged; cell walls between
lamina cells not bulging; leaf cells smooth; alar cells 2-stratose, well
differentiated, not extending to costa; proximal laminal cells elongate,
pitted, (45–)78–129(–156) × (5–)9–10(–14) µm; distal laminal cells shorter,
sinuose, pitted, (42–)64–68(–115) × (4–)9–10(–13) µm. Sexual
condition pseudomonoicous; dwarf male plants on stem rhizoids of female
plants; interior perichaetial leaves abruptly long-acuminate,
convolute-sheathing. Seta usually aggregate, 3–6 per
perichaetium, brown or reddish brown, 1.5–4 cm. Capsule arcuate,
inclined to horizontal, yellowish brown or reddish brown, 2–3.5 mm, furrowed
when dry; operculum 2–4 mm. Spores 12–24 µm. Capsules mature in spring. Commonly on humus, soil over acidic or
calcareous rocks, and decaying wood in deciduous or more often coniferous
forests, occasionally in bogs, fens, and swamps; 10–2100 m; Alta., B.C.,
Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que.,
Sask., Yukon; Alaska, Colo., Conn., Idaho, Ill., Ind., Iowa, Ky, Maine, Md.,
Mass., Mich., Minn., Mo., Mont., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Oreg.,
Pa., S.Dak., Tenn., Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; Asia. This Dicranum is the largest,
the most conspicuous and the most easily recognized species in the genus in
North America. The species is
immediately recognized by the large stems, 4–15 cm, with a dense mat of
whitish or reddish tomentum, giving the stems a thickened appearance, by the
shiny, strongly undulate, wide-spreading leaves with margins strongly toothed
in distal 1/2 and by the clustered sporophytes (3–6 per perichaetium). Microscopically, the species is readily
distinguished by the elongate, abundantly pitted cells throughout the leaf
and by the toothed ridges on the abaxial surface of the costa in the distal
part of the leaf. Dicranum
polysetum is one of the few species in North America that has no apparent
intergradations with any other species of Dicranum. Dicranum polysetum is common in southeastern Canada,
northeastern United States and the Canadian Rocky Mountains where it extends
south to Wyoming and Colorado, occurring in both states in a small number of
localities. It is rare west of the
Rockies where it is known from only a few localities in northwestern Montana,
southern Idaho and northeastern Washington and Oregon. The Nunavut record is from W. Peterson
(1979). 2. Dicranum
scoparium Hedwig, Spec. Musc. 126. 1801 Dicranum latifolium J. J. Amann Plants
in loose to dense
tufts, light to dark green, glossy to sometimes dull. Stems
2–10 cm, tomentose with white to brown rhizoids. Leaves very
variable, usually falcate-secund, rarely straight and erect, slightly
contorted and crisped when dry, sometimes slightly rugose or undulate,
(4–)5–8.5(–15) × 0.8–1.8 mm, concave proximally, keeled above, lanceolate,
apex acute to somewhat obtuse, margins strongly serrate in distal 1/3 or
rarely slightly serrulate; laminae 1-stratose; costa percurrent, excurrent,
or ending before apex, 1/10–1/5 width of leaves at base, usually with 2–4
toothed ridges above on abaxial surface, with a row of guide cells, 2 thin
stereid bands, adaxial epidermal layer of cells not differentiated, abaxial
layer interrupted by several enlarged cells that form part of the abaxial
ridge, not extending to the apices; cell walls between lamina cells not
bulging; leaf cells smooth; alar cells 2-stratose, well- differentiated,
sometimes extending to costa; proximal laminal cells linear-rectangular,
pitted, (25–)47–100(–132) × (5–)7–12(–13) µm; distal laminal cells shorter,
broad, sinuose, pitted, (11–)27–43(–53) × (5–)8–12(–20) µm. Sexual
condition pseudomonoicous or dioicous; dwarf males on rhizoids of female
plants or male plants as large as females; interior perichaetial leaves
abruptly long-acuminate, convolute-sheathing. Seta solitary,
rarely 2 per perichaetium, yellowish brown to reddish brown, 2–4 cm. Capsule
arcuate, inclined to horizontal, yellowish brown or reddish brown, 2.5–4 mm,
smooth to striate when dry; operculum 2–3.5 mm. Spores 14–24 µm. Capsules mature in spring. Soil, humus, humus over rocks, decaying
stumps and logs, tree bases in dry to mesic woodlands; sometimes bogs, fens
and swamps; 50–2900 m; Greenland; Alta., B.C., Man., N.B., Nfld. and Labr.,
N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz.,
Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa,
Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., N.H.,
N.J., N.Mex., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn.,
Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Mexico; Europe; Asia; Australia;
New Zealand. Undoubtedly the most polymorphic
species of Dicranum in North America.
It is commonly called the broom moss because the leaves are “swept” or
turned in the same direction.
However, the habit of the leaves varies from strongly falcate-secund,
i.e., the swept state, to straight and erect, especially prevalent in
northern plants. The leaf shape
varies from the typical lanceolate and long-acuminate to the odd
ovate-lanceolate and short-acuminate.
The leaves are typically smooth, in sharp contrast to the strongly
undulate leaves of D. polysetum, but on rare occasion they can be
somewhat undulate-rugose. The leaf
margins are usually distinctly toothed in the distal third but at times
plants in some populations have extremely weak serrations, appearing nearly
entire. The costae vary in extent
from subpercurrent to shortly excurrent.
The abaxial surface of the costae have two to four toothed ridges,
compared to the two in D. polysetum, but in some forms they are almost
nonexistent. The distal areolation of
the leaves seems to remain constant in the myriad forms of D. scoparium,
the cells are short-sinuose with pitted walls, generally containing
conspicuous oil-drops. Plants growing in Arctic North America
and those in extremely wet habitats, such as bogs, often have a different
superficial appearance. The leaves
are straight, erect, ovate-lanceolate, short-acuminate with weak serrations
on the margins, and the abaxial ridges on the costae are poorly
developed. Sometimes the plants have
distal shoots with abnormal appearing leaves that are shorter and broader
than those below. Some of these
collections have been referred to D. latifolium J. J. Amann, a species
that I consider to be a synonym of D. scoparium. Further field and laboratory studies are
required to clarify the taxonomic status of these plants. In the sterile
state, large-leaved plants of D. scoparium can be confused with D.
majus. The latter is immediately
distinguished by a double row of guide cells, instead of the single row in
the former, thicker stereid bands, distal cells that are narrower and more
elongate and costae that have small teeth or serrulations distally on the
abaxial surface instead of the characteristic 2–4-toothed ridges of D.
scoparium. When fruiting, the solitary, rarely paired, sporophytes of D.
scoparium distinguish it from D. majus which has multiple sporophytes,
2–5 per perichaetium. 3. Dicranum
howellii Renauld & Cardot, Rev. Bryol. 15:
70. 1888 E Plants in loose to dense tufts, green to
yellowish green, glossy. Stems 2–8 cm, densely tomentose with
white to reddish brown rhizoids. Leaves falcate-secund to straight and
erect, sometimes slightly crisped, smooth, (5–)8–10(–12) ´ 0.8–1.5 mm, concave proximally, keeled
or tubulose above, lanceolate, apex acute, margins strongly serrate in distal
part, entire proximally; laminae 1-stratose; costa ending before apex to
shortly excurrent, 1/12–1/5 width of leaves at base, with 2, rarely 4,
toothed ridges on abaxial surface extending from ca. leaf middle nearly to
apex, rarely almost smooth, with a row of guide cells, 2, thin stereid bands,
adaxial epidermal layer of cells not differentiated, abaxial layer
interrupted by several enlarged cells that form part of abaxial ridge, not
extending to apices; cell walls between lamina cells not bulging; leaf cells
smooth; alar cells 2-stratose, well differentiated, sometimes extending to
costa; proximal laminal cells linear-rectangular, pitted, (52–)65–105(–120) ×
(10–)12–18(–22) µm; distal laminal cells shorter, sinuose, pitted,
(42–)54–90(–108) × (10–)12–14(–16) µm.
Sexual condition pseudomonoicous or dioicous; dwarf males on rhizoids
of female plants or male plants as large as females and growing intermixed or
in ± separate tufts; interior perichaetial leaves gradually acuminate, not or
partially convolute-sheathing. Seta solitary, sometimes 2 per
perichaetium, yellow to reddish brown, 1.5–4 cm. Capsule arcuate,
inclined to horizontal, yellow to dark reddish brown, 2–3.8 mm, smooth to
striate when dry; operculum 2–3.8 mm.
Spores 18–26 µm. Capsules mature in spring. Soil, humus, humus over rocks, rotting logs
and stumps, tree trunks and bases of trees, sometimes in bogs; 20–600 m;
B.C.; Alaska, Calif., Idaho, Mont., Oreg., Wash. Dicranum howellii is one of five endemic species of
North America, occurring only in the northwestern part of the continent. It is closely related to the common and
nearly ubiquitous D. scoparium.
The shape of the interior perichaetial leaves is the most reliable way
to distinguish the two. Gradually
acuminate interior perichaetial leaves that loosely surround the seta are
characteristic of D. howellii while D. scoparium has abruptly
acuminate interior perichaetial leaves that are convolute-sheathing around
the seta. The exterior perichaetial
leaves also exhibit the same characteristic but to a lesser extent. The interior perichaetial leaves of D.
howellii are also longer and narrower than those of the latter. Other less significant features of D.
howellii are the consistently glossy, long leaves, mostly 8–10 mm, with
long distal cells, averaging 54–90 mm, and the common occurrence of only two, rarely four,
serrated ridges on the abaxial surface of the costae. Dicranum scoparium by comparison
has glossy to sometimes dull leaves that are often shorter, mostly 5–8.5 mm,
with shorter distal cells, averaging 27–43 mm, and the costae usually have four, rarely two, serrated
ridges on the abaxial surface. The
perichaetial leaves are undoubtedly the most important feature separating the
two species, as well as being the easiest to observe. Eastern North American plants of D.
scoparium all have the abruptly acuminate perichaetial leaves that are
characteristic of the species as do plants elsewhere in the world. The perichaetial leaf character was one
reason D. howellii was believed to be a distinct species by F. Renauld
and J. Cardot (1889, Pl. 12B) who first illustrated that character and this
remains the most significant reason for maintaining it as a distinct species.
4. Dicranum
bonjeanii De Notaris in Lisa, Elenco Muschi Torino
29. 1837 Plants in loose tufts, yellow to yellowish
green, glossy. Stems 2–8 cm, scarcely tomentose with
whitish to reddish brown rhizoids. Leaves erect-spreading, sometimes
nearly appressed, flexuose, little changed when dry, undulate or rugose,
(3.5–)4–5.5(–6) × 1–1.5 mm, flat to ± concave proximally, subtubulose above,
from a lanceolate base to a short, broadly acute apex, distal part of stem
often with ovate, short-subulate, blunt leaves, margins serrate in distal
1/2; laminae 1-stratose; costa ending just before the apex, sometimes with 2
poorly developed toothed ridges above on abaxial surface, 1/13–1/8 width of
leaves at base, row of guide cells, 2 thin stereid bands, adaxial epidermal
layer of cells not differentiated, abaxial layer with a few (usually 2) cells
differentiated in distal part of leaves; cell walls between lamina cells not
bulging; leaf cells smooth; alar cells 2-stratose, well-differentiated,
sometimes extending to costa; proximal laminal cells long, sinuose, pitted,
(28–)47–71(–113) × (–5)9–11(–14) µm; distal laminal cells short-linear,
sinuose, pitted, (25–)36–51(–73) × (5–)8–14(–20) µm. Sexual
condition pseudomonoicous; dwarf males on rhizoids of female plants;
interior perichaetial leaves abruptly long-acuminate,
convolute-sheathing. Seta solitary, rarely 2 per
perichaetium, yellowish brown to reddish brown, 2.5–3.5 cm. Capsule
arcuate, inclined to horizontal, yellow-brown, 2.5–3 mm, striate when dry;
operculum 1.7–3 mm. Spores 14–28 µm. Capsules mature in spring. Mainly in eutrophic fens, sometimes on
calcareous soil or rocks; 60–1300 m; Greenland; Alta, B.C., Man., Nfld. and
Labr., N.W.T., N.S., Ont., P.E.I., Que., Sask.; Alaska, Colo., Idaho, Maine,
Mich., Ohio, Oreg., Mass., Pa., Vt., Wash., Wis., Wyo.; Europe; Asia. Dicranum bonjeanii is a difficult species to distinguish from
the myriad forms of the polymorphic D. scoparium. Indeed, few of the many herbarium
collections from North America named D. bonjeanii are actually that
species or at least what is known as that species. It has been noted before (R. R. Ireland 1982) that it may be
merely an enviromental form growing in a calcareous, often hydric
habitat. Most Europeans (e.g., A. J.
E. Smith 1978; E. Nyholm 1986) recognize the species as it occurs in Europe
and some that come to North America to collect (e.g., R. Tuomikoski et al. 1973) find the species to be
distinct on this continent. However,
H. A. Crum and L. E. Anderson (1981) and other North American bryologists
have synonymized the species with D. scoparium. D. Briggs (1965), who cultivated and
studied British plants of both D. bonjeanii and D. scoparium
under controlled environmental conditions, found that while they show wide
intraspecific variation, especially in regard to the leaf habit and
undulation, he thought they should be kept as separate taxa because each
species maintains a distinctive array of gametophytic characters. Also, both
species are distinctive ecologically:
D. bonjeanii prefers eutrophic fens, whereas D. scoparium
usually grows in decidedly dry to mesic woodlands, on soil, humus, humus over
rock, stumps and logs, tree bases, etc. The species is best known by its
glossy, mostly erect, nearly straight, undulate leaves with broadly acute
apices, weakly developed marginal teeth and, what is most important, two
poorly developed ridges present only near the leaf apex on the abaxial
surface of the costa. The two ridges on the costa, best seen in cross
section, will distinguish the species most of the time from D. scoparium
which usually has four ridges on its costae. Its preference for eutrophic fens
and other calcareous habitats, while avoiding acid substrates, is important
from an ecological standpoint and helps give a clue to the identity of the
species. The Maine record is from B. Allen
(1998b). 5. Dicranum
leioneuron Kindberg in Macoun, Bull. Torrey Bot.
Club 16: 92. 1889 Plants in loose tufts, yellowish green,
glossy. Stems 5–8 cm, scarcely tomentose with whitish to reddish brown
rhizoids. Leaves erect or spreading, distal leaves with twisted apices when
dry, slightly rugose, (3.5–)5–7(–8) × 1–1.5 mm, concave proximally, tubulose
above, from an ovate-lanceolate base to a long or short subula, broadly
acute, some leaves short, ovate, somewhat obtuse, forming julaceous regions,
in the middle or basal part of the stems, margins not or slightly serrate in
distal part, somewhat involute in the middle part; laminae 1-stratose; costa
ending before the apex, 1/13–1/8 width of leaves at base, smooth or sometimes
distal part with 2 weakly serrated ridges on abaxial surface, row of guide
cells, 2 stereid bands, adaxial and abaxial epidermal layers of cells not
differentiated or sometimes a few cells in the abaxial layer differentiated;
cell walls between lamina cells not bulging; leaf cells smooth; alar cells
2-stratose, differentiated, not extending to costa; proximal laminal cells
elongate-sinuose, pitted, (42–)75–87(–107) × (7–)8–10(–16) µm; distal laminal
cells short, sinuose, pitted, (16–)30–65(–79) × (7–)9–13(–16) µm. Sexual
condition pseudomonoicous; dwarf males on rhizoids of female plants;
interior perichaetial leaves abruptly long-acuminate,
convolute-sheathing. Seta solitary, yellow, yellowish
brown or reddish yellow, 2–4 cm. Capsule arcuate, inclined, yellow to
yellowish brown, 2–3.5 mm, smooth, ± furrowed when dry; operculum 1.5–2
mm. Spores 14–24 µm. Capsules mature in spring. Primarily in hummocks in ombrotrophic and
oligotrophic peatlands; 10–1100 m; B.C., N.B., Nfld. and Labr., N.W.T., N.S.,
Ont., P.E.I., Que., swYukon; s Alaska; nw Europe. This species is apparently closely
related to Dicranum bonjeanii.
It is best distinguished by the subulate leaves with twisted apices
when dry, the usual occurrence of julaceous stem portions with broad, short,
concave, and somewhat obtuse leaves in contrast to the longer, narrower,
subulate, and acute leaves of the other stem portions. Its occurrence only in
hummocks in peatlands also is a clue to its identity. The plants rarely produce sporophytes but
in any event they cannot be distinguished from those of the other species in
section Dicranum. The species
probably occurs in peatlands in northeastern United States and it should be
looked for in that region. 6. Dicranum
majus Turner, Muscol. Hibern. Spic. 58. 1804 Plants in loose tufts, green to light green,
glossy to somewhat dull. Stems 3–16 cm, naked or with a few
whitish rhizoids, rarely moderately tomentose, rhizoids(micronemata) in rows
above each leaf. Leaves somewhat sparse, falcate-secund or erect-patent, flexuose
or straight, little changed when dry, usually smooth, (6–)8–11.5(–15) × 1–2
mm, concave proximally, tubulose above, from a lanceolate to ovate-lanceolate
base, gradually narrowed to a long, falcate-secund or straight, acute apex,
margins serrate in distal 1/2, sometimes slightly serrulate above to almost
entire; laminae 1-stratose or with few 2-stratose regions on or near the
margins; costa percurrent to shortly excurrent, 1/12–1/7 width of leaves at
base, toothed distally or serrulate to nearly smooth on abaxial surface, with
a double row of guide cells that is sometimes interrupted, 2 stereid bands
extending to apex, adaxial epidermal layer of cells with some cells
differentiated, abaxial layer completely differentiated; cell walls between
lamina cells not bulging; leaf cells smooth or abaxially prorate or toothed
above; alar cells 2-stratose or multistratose, well differentiated, not
extending to costa; proximal laminal cells elongate, pitted,
(42–)71–112(–140) × (5–)9–10(–15) µm; distal laminal cells shorter, linear to
oval, pitted, (42–)47–61(–99) × (7–)10–11(–17) µm. Sexual condition
pseudomonoicous; dwarf males among rhizoids of female plants; interior
perichaetial leaves abruptly long-acuminate, convolute-sheathing. Seta
aggregate, 2–5 per perichaetium, rarely solitary, yellow to light brown,
2.5–5 cm. Capsule arcuate, inclined to horizontal, dark brown or yellowish
brown, 2–3.5 mm, smooth to faintly striate when dry; operculum 2–3 mm. Spores
14–19 µm. Varieties number worldwide? (2 in the
flora): North America, Europe, Asia. This is the only North American species
of Dicranum with a double row of guide cells. It is a distinctive species with oceanic
tendencies and, in North America it commonly grows in northern coastal
localities on both sides of the continent, occasionally occurring inland in
very moist habitats. 1. Leaves falcate-secund, 8–15 mm, margins
serrate in distal 1/2; costa toothed distally on abaxial surface, with a
double row of guide cells................................... 1. Leaves erect-patent, 6–8 mm, margins slightly
serrulate above to almost entire; costa serrulate to nearly smooth distally
on abaxial surface, with an interrupted double row of guide cells........................... 6a. Dicranum
majus Turner var. majus Plants
in loose tufts, green
to light green, glossy. Leaves falcate-secund, flexuose, 8–11.5(–15) mm, margins serrate
in distal 1/2; costa percurrent to shortly excurrent, toothed distally on
abaxial surface, with a double row of guide cells. Capsules mature in spring. Humus, soil, soil over rocks, rotten wood
in coniferous woods, bogs, and tundra; 0–1500 m; Greenland; Alta., B.C.,
Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que.,
Yukon; Alaska, Maine, Mass., R.I., Wash.; Europe; Asia. The var. majus is known by its
glossy, long (8–15 mm), falcate-secund leaves with serrate margins in the
distal half, by its costae with two rows of guide cells (seen in cross
section), the abaxial surface toothed and not ridged distally, and by its
aggregate setae (2–5 per perichaetium). 6b. Dicranum
majus var. orthophyllum Milde, Bryol. Siles. 71. 1869 Plants in loose tufts, mostly light green,
somewhat dull. Leaves erect-patent, 6–8 mm, margins slightly serrulate distally
to almost entire; costa serrulate to nearly smooth distally on abaxial
surface, with an interrupted double row of guide cells. Capsules mature in spring. Humus, sand, and rock in the tundra;
40–1500 m; B.C., Man., N.W.T., Que., Yukon; Alaska; Europe. This is an extremely weak Arctic
variety that differs from the typical var. majus in only a few minor
characters. The plants immediately
appear different because of the erect-patent, short leaves instead of the
long, falcate-secund leaves of the typical var. majus. More collections are needed from many
Arctic localities to better understand this variety, which may only be an
environmental form. The Alaska record
is from I. A. Worley & Z. Iwatsuki (1970). 7. Dicranum
rhabdocarpum Sullivant, Mem. Amer. Acad. 4: 172. 1849 Orthodicranum rhabdocarpum (Sullivant) Holzinger Plants in dense tufts, green to yellowish
green or brownish, ± glossy. Stems 2–8 cm, tomentose with reddish
brown rhizoids. Leaves straight or nearly so,
spreading, little changed when dry, smooth, 3–5.5 × 0.6–1.2 mm, concave or
tubulose proximally, tubulose to slightly keeled above; ovate-lanceolate,
apex obtusely acute, margins serrate near apex; laminae 1-stratose; costa
subpercurrent to percurrent, 1/10–1/8 width of leaves at base, smooth or
weakly toothed on abaxial surface near apex, with a row of guide cells, 2
weak stereid bands, at least in basal part of leaf, adaxial and abaxial
epidermal layers of cells not differentiated; cell walls between lamina cells
not bulging; leaf cells smooth; alar cells 1- or 2-stratose in part, differentiated,
not extending to costa; proximal laminal cells linear-rectangular, pitted,
(45–)65–120(–150) × (13–)16–17(–19) µm; distal laminal cells shorter, narrow,
pitted or with few pits, (20–)30–45(–60) × (5–)8–10(–13) µm. Sexual
condition dioicous; male plants about as large as the female or slightly
smaller; interior perichaetial leaves ± abruptly acuminate,
convolute-sheathing. Seta solitary, rarely 2 per
perichaetium, yellow to reddish brown, 1.5–3 cm. Capsule erect,
straight or nearly so, brown, 1.5–3.5 mm, furrowed when dry; operculum
1.6–2.8 mm. Spores 13–19 µm. Capsules mature in summer. Soil, soil over rocks, peaty soil or
rotten wood; 1600–3300 m; Ariz., Colo., N.Mex., Wyo.; Mexico (Chihuahua,
Tamaulipas); West Indies (Dominican Republic); Central America (Guatemala). This is easily recognized species that
occurs in the flora area only in the Rocky Mountains and the mountains of
Arizona. It is the only species in
the section Dicranum that has erect, straight to weakly arcuate
capsules. Other important
distinguishing features are the ovate-lanceolate, straight, obtusely acute,
1-stratose leaves with alar cells 1- or 2-stratose in part and the
subpercurrent to percurrent costae that are smooth or weakly toothed on the
abaxial surface near the leaf apex. Dicranum
rhabdocarpum has been placed in the segregate genus Orthodicranum
by J. M. Holzinger (1925) and other bryologists mainly because of its
straight and erect capsules. However,
it differs from taxa commonly placed in that genus, i.e., D. flagellare,
D. fulvum, D. montanum, D. strictum and D. viride,
by the elongate, pitted cells and the alar cells that are sometimes
2-stratose. 8. Dicranum
undulatum Bridel, J. f. Bot. 1800, 1(2): 294. 1801, not G. F. Weber & C. Mohr 1803 Dicranum bergeri Blandow Plants in dense compact tufts, green to
yellowish brown, shiny, rarely somewhat dull. Stems 3–8(–17) cm,
densely tomentose with reddish brown rhizoids. Leaves
erect-appressed or sometimes slightly falcate or flexuose, somewhat contorted
when dry, apex often twisted, weakly to strongly undulate, (4.5–)5–7.5(–11) ×
0.7–1.2 mm, concave proximally, keeled above, lanceolate to
oblong-lanceolate, broadly acute, rarely narrowly acute, margins plane,
sometimes involute at base, broadly recurved at apex, entire proximally,
serrulate to serrate in distal 1/2; laminae 1-stratose, sometimes with a few
2-stratose regions; costa strong, ending before apex, sometimes nearly
percurrent, 1/6–1/3 width of leaves at base, smooth to serrulate above on
abaxial surface, with a row of guide cells, 2 stereid bands extending to
apex, adaxial epidermal layer of cells not differentiated, abaxial layer
diffferentiated; cell walls between lamina cells weakly to strongly bulging
abaxially and adaxially; leaf cells smooth to ± papillose near apex on
abaxial surface; alar cells 2-stratose, differentiated, not extending to
costa; proximal laminal cells elongate, incrassate, pitted, (22–)38–61(–79) ×
(2)4–6(8) µm; median laminal cells rectangular, pitted; distal laminal cells
short-rectangular to irregularly angled, not pitted, (7–)11–14(–28) ×
(4–)11–12(–17) µm. Sexual condition pseudomonoicous;
dwarf males on stem rhizoids of female plants; interior perichaetial leaves
abruptly acuminate, convolute-sheathing.
Seta solitary, yellow to
brown, 2–4 cm. Capsule arcuate, inclined, yellow to yellowish brown or reddish
brown, 2–2.8 mm, furrowed when dry, ± contracted below mouth; operculum 2–3
mm. Spores 14–28 µm. Capsules mature in spring. Usually in wet habitats, especially bogs
in Sphagnum hummocks, fens, swamps, marshes, margins of lakes;
sometimes on or among rocks, rock outcrops and cliffs; occasionally in mesic
woods or on dry bluffs on soil, rotten wood, or humus; 10–2200 m; Greenland;
Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont.,
P.E.I., Que., Sask., Yukon; Alaska, Calif., Colo., Conn., Ind., Maine, Mass.,
Mich., Minn., Mont., N.H., N.J., N.Y., N.C., Ohio, Pa., S.Dak., Vt., Wash.,
W.Va., Wis.; Europe; Asia. This is a boreal species that is
distinctive because of the yellowish green or yellowish brown, shiny,
erect-appressed, lanceolate to oblong-lanceolate, undulate, keeled leaves,
the leaf margins that are serrulate to serrate, and broadly recurved in the
distal half, the leaf apices that are usually broadly acute, rarely narrowly
acute, and the costae that are mostly subpercurrent or sometimes percurrent,
smooth to serrulate above on abaxial surface. When the leaf apices are narrow, ± acute, and the costa
percurrent, as some D. undulatum plants are on rare occasion, the
species when sterile can be confused with D. ontariense. Dicranum undulatum has shiny leaves
with twisted apices when dry compared to the more dull leaves that are
variously contorted in D. ontariense.
When sporophytes are present the aggregate setae (2–5 per
perichaetium) of D. ontariense will immediately distinguish it from D.
undulatum which has solitary setae.
This species recently has been
introduced on the University of California Berkeley Campus in a
lawn-landscaping area; this is the only California locality where it has been
found. The plants are sterile but
appear morphologically similar to those growing in native habitats in other
parts of North America. The Colorado
record is from R. R. Ireland in E. Lawton (1971). 9. Dicranum
ontariense W. L. Peterson, Canad. J. Bot. 55:
988. 1977 E Dicranum drummondii Sullivant not J. K. A. Müller Plants in loose tufts, dark to light green,
dull. Stems 3–8 cm, densely tomentose below with reddish brown
rhizoids. Leaves falcate-secund,
flexuose, contorted when dry, slightly undulate, (5–)6.5–9(–10) mm × 1–1.5
mm, concave below, keeled above, from a lanceolate base to a long-acuminate
apex, margins plane, strongly serrate above; laminae 1-stratose, rarely with
2-stratose regions on margins or near costa; costa percurrent to slightly
excurrent, 1/6–1/5 width of leaves at base, papillose to spinose above on
numerous, low abaxial ridges, with a row of guide cells, 2 thick,
well-developed stereid bands above and below extending to apex, adaxial
epidermal layer of cells not differentiated, abaxial layer differentiated;
cell walls between lamina cells not bulging or weakly bulging; leaf cells
prorate on abaxial surface, sometimes papillose adaxially; alar cells
2-stratose, rarely 3-stratose in parts, differentiated, not extending to
costa; proximal laminal cells rectangular, pitted, (22–)40–64(–126) ×
(2–)7–8(–10) µm; distal laminal cells short-rectangular to rectangular, not
pitted, ± in longitudinal rows, marginal cells usually more elongate, some
distal cells with long tooth-like projections, scattered on abaxial surface,
(7–)12–18(–42) × (5–)8–12(–16) µm. Sexual condition pseudomonoicous;
dwarf males on stem rhizoids of female plants; interior perichaetial leaves
abruptly long-acuminate, convolute-sheathing. Seta often aggregate
2–5 per perichaetium, sometimes solitary, yellow, brown, or reddish yellow,
2–3.5 cm. Capsule arcuate, inclined to horizontal, yellow to light brown,
2–3 mm, furrowed when dry; operculum 1.5–3 mm. Spores 9–20 µm. Capsules mature in spring. Humus, soil, or soil over rocks, rarely
rotten logs or stumps, usually in mesic to dry coniferous woods, sometimes
swamps and bogs; 60–1200 m; Alta., Man., N.B., Nfld. and Labr., N.S., Ont.,
P.E.I., Que., Sask.; Maine, Mass., Mich., Minn., N.H., N.J., N.Y., N.C.,
Ohio, Pa., Tenn., W.Va., Wis., Wyo. This North American endemic species was
previously mistaken for Dicranum drummondii J. K. A. Müller, a
predominately Eurasian species which was unknown on this continent until it
was discovered just recently on the Aleutians Islands. W. Peterson (1977) clarified the taxonomic
position of D. ontariense, while P. Isoviita (1977) amplified on the
complex nomenclatural details of why it must be recognized as a species
distinct from D. drummondii.
The main distinguishing features of D. ontariense are the dark
to light green, dull, falcate-secund, flexuose tipped, slightly undulate
leaves, contorted when dry, keeled above from a lanceolate base to a long-acumination,
the leaf apices papillose to spinose above on abaxial surface, the laminae
1-stratose except for occasional 2-stratose regions on margins, the leaf
margins plane, strongly serrate above, and the usually multiple sporophytes,
2–5 per perichaetium. This species is sometimes confused with
an environmental form of D. undulatum that has nearly percurrent
costae and more-or-less acute apices.
The aggregate setae of D. ontariense will immediately
distinguish it from that form which has solitary setae. The dull leaves that are contorted when
dry, and the leaf apices that are long-acuminate, abundantly spinose on the
abaxial surface, are other superficial features to distinguish it from D.
undulatum, which has shiny, usually broadly acute, smooth or serrulate
leaf apices. Also, on occasion, D.
ontariense can be confused with large forms of D. condensatum when
sterile. The thin-walled,
short-rectangular to quadrate distal-median cells in more or less regular
rows of the former will distinguish it from the latter, which has irregularly
shaped cells that are thick-walled and usually not in well defined rows. When fruiting, the aggregate setae on some
of the plants of D. ontariense will immediately distinguish it from D.
condensatum, which has solitary setae. The Alberta record is from W. Peterson
(1979). 10. Dicranum
drummondii J
.K .A. Müller, Syn. 1: 356. 1848 Dicranum elatum Lindberg; D. robustum Bruch,
Schimper & W. Gümbel Plants in loose tufts, yellowish green to yellowish
brown below, shiny to dull. Stems 5–11 cm, densely tomentose
below with reddish brown rhizoids. Leaves erect and compressed to
somewhat flexuose, curled to flexuose at apices when dry, undulate or rugose,
(7–) 8–10 (–12) mm × 1.5–2 mm, concave below, keeled above, from an
oblong-ovate base to a long-acuminate apex, margins incurved to tubulose
below, plane and strongly serrate above; laminae 1-stratose below, sometimes
a few scattered 2-stratose regions above; costa percurrent to shortly excurrent,
1/6 –1/10 width of leaves at base, papillose to serrate above on abaxial
surface, without lamellae, with a row of guide cells, 2 stereid bands above
and below extending to apex, adaxial epidermal layer of cells with a few
cells slightly larger than the stereids differentiated, abaxial layer
completely differentiated with cells slightly larger than the stereids; cell
walls between lamina cells not bulging; leaf cells smooth or a few cells
prorate on abaxial surface; alar cells 2-stratose, differentiated, extending
to costa; proximal laminal cells irregularly rectangular, often narrowed at
ends, narrow and elongate on margins, pitted, (67–) 82–98 (–112) × (5–) 6–8
(–9) µm; distal laminal cells round, oblong, somewhat rectangular, with a few
pits (9–) 13–19 (–30) × (3–) 6–9 (–12) µm.
Sterile, no sex organs
seen. [Sexual condition pseudomonoicous, male plants on leaves of female
plants. Interior perichaetial leaves
abruptly subulate, convolute-sheathing.
Seta 2–3 per perichaetium,
sometimes solitary, yellowish, 3–5 cm.
Capsule arcuate, inclined
to horizontal, yellowish brown, 2.5–3.5 mm, striate when dry; operculum 2.3–3
mm. Spores 14–18 µm. ?Mature capusules unknown. Large clones in mesic mire; Alaska;
Europe; Asia (China, Japan, Korea, Russia). Dicranum drummondii, primarily an Eurasian species, was
for years confused with the endemic North American species, Dicranum
ontariense W. L. Peterson (see discussion under D.ontariense). It was only recently (August 2000) that W.
B. Schofield, S. S. Talbot and S. L. Talbot made the first and only
collection of the species, which was sterile, from Attu Island in the
Aleutian Islands, Alaska. The species
is best recognized by its robust size, stems 5–11 cm, its leaves yellowish
green to yellowish brown, undulate or rugose, erect and compressed, becoming
flexuose at the tips when dry, concave below and keeled above, with an
oblong-ovate base, becoming long-acuminate at apex, margins strongly toothed
above, and costa percurrent to shortly excurrent, without lamellae. Microscopically, distinguishing characters
are the leaves in the distal part with round, oblong, somewhat rectangular
cells with few pits, cells smooth or prorate on abaxial surface, in cross
section the lamina with a few scattered 2-stratose cells, cells walls between
the lamina cells not bulging, and costa with a few cells differentiated on
the adaxial epidermal surface. 11. Dicranum
condensatum Hedwig, Spec. Musc. 139. 1801, not plate 34 E Dicranum sabuletorum Renauld & Cardot Plants in ± dense tufts, light green to
yellowish brown, dull. Stems 1–9 cm, densely tomentose below
with reddish brown rhizoids. Leaves erect-spreading, flexuose, ±
curled at the tips when dry, slightly undulate or rugose, (2–)3.5–4.5(–7) ×
0.5–1 mm, concave below, strongly keeled above, oblong-lanceolate, with a
broad lanceolate base gradually narrowing to a short-acuminate apex, margins
serrulate in distal 1/2, involute in central part; laminae 1-stratose, with a
few 2-stratose regions; costa percurrent to shortly excurrent, 1/10–1/5 width
of leaves at base, strong, smooth or papillose to toothed above on abaxial
surface, abaxial ridges lacking, with a row of guide cells, 2 thick stereid
bands extending well into the apex, adaxial epidermal layer of cells not
differentiated, abaxial layer differentiated; cell walls between lamina cells
strongly bulging; leaf cells papillose above on abaxial surface, sometimes
nearly smooth; alar cells 2-stratose, differentiated, not extending to costa;
proximal laminal cells elongate, pitted, (25–)41–56(–112) × (5–)6–7(–10) µm,
abruptly shorter towards the apex; distal laminal cells quadrate, irregularly
angled, rounded or rectangular, not or indistinctly pitted, cell walls
unequally thickened, (5–)7–8(–20) × (5)7–8(12) µm. Sexual condition
pseudomonoicous; dwarf males on stem rhizoids of female plants; interior
perichaetial leaves abruptly short-acuminate, convolute-sheathing. Seta
solitary, rarely 2 per perichaetium, yellowish, 1–4 cm. Capsule
arcuate, inclined to horizontal, yellowish brown, 1.5–3 mm, furrowed when
dry, slightly contracted below the mouth; operculum 1.5–2.5 mm. Spores
19–26 µm. Capsules mature in spring. Exposed sandy soil, often in pine woods,
frequently over sandstone and limestone; 0–700 m; N.B., N.S, Que.; Ala.,
Ark., Del., D.C., Fla., Ga., Ill., Kans., Ky., La., Maine, Md., Mass., Mich.,
Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn.,
Tex., Va., W.Va. This is a common species endemic to
eastern North America. It is known in
the field by its occurrence on sandy soil, by its light green to yellowish
brown, dull plants in compact, dense tufts, by its erect-spreading,
oblong-lanceolate leaves, narrowing to a short-acuminate apex, keeled above,
somewhat undulate or rugose, curled at tips when dry and by its solitary
setae with an arcuate, inclined to horizontal capsule. The papillose leaf cells with strongly
bulging walls between the cells and the irregularly angled median and distal
cells with nonpitted walls are distinctive microscopic characters. Dicranum spurium is the species most commonly confused
with D. condensatum. Both species occur on sandy soil with their
ranges overlapping. The former occurs
farther northward, where it is found in Newfoundland, while the latter occurs
farther to the south, where it extends its range to the tip of Florida. Dicranum spurium has broader
leaves, the broadest point near the leaf middle rather than near the base
like D. condensatum, and leaves that are tubulose above (most
noticeable when wet) rather than keeled.
Rarely, D. condensatum can be mistaken for D. ontariense
as discussed under that species. 12. Dicranum
spurium Hedwig, Spec. Musc. 141. 1801 Plants in loose tufts, green to yellowish
green or yellowish brown, dull. Stems 2–11 cm, densely tomentose
below with reddish brown rhizoids, interruptedly foliate, the leaves crowded
in some parts forming swollen, globose regions. Leaves
erect-spreading, arched and loosely imbricate with contorted apices when dry,
± undulate to rugose, (2.5–)5–6.5(–9) × 1–1.7 mm, concave below, tubulose
above, acute, ovate at base, widest point at or somewhat below middle,
margins serrulate to serrate in distal 1/2, plane to involute; laminae
1-stratose or with 2-stratose regions near costa and on margins; costa percurrent
to shortly excurrent, 1/8–1/4 width of leaves at base, serrulate or toothed
above on abaxial surface, abaxial ridges lacking, with a row of guide cells,
2 stereid bands extending to apex, adaxial epidermal layer of cells not
differentiated, abaxial layer differentiated; cell walls between lamina cells
weakly to strongly bulging; leaf cells strongly papillose above on abaxial
surface, sometimes a few papillae on adaxial surface; alar cells 2-stratose,
distinctly differentiated, not extending to costa; proximal laminal cells
elongate, pitted, (30–)49–68(–101) × (5)10–11(15) µm, abruptly shorter in
distal 1/2 of leaf; distal laminal cells short, not or indistinctly pitted,
cell walls irregularly thickened, (7–)11–12(–23) × (5–)7–13(–20) µm. Sexual
condition pseudomonoicous; dwarf males on rhizoids of female plants;
interior perichaetial leaves abruptly short-acuminate,
convolute-sheathing. Seta solitary, reddish yellow or
brown, 1–3 cm. Capsule arcuate, inclined to horizontal, yellowish brown to brown,
1.5–2.5 mm, contracted below mouth and furrowed when dry; operculum 1.5–2.5
mm. Spores 16–24 µm. Capsules mature in spring. Sandy soils, decayed logs, acidic rock,
humus over exposed bluffs or outcrops, in pine woods, sometimes bogs; 0–1400
m; Nfld. and Labr., N.S., Ont., P.E.I., Que.; Ark., Conn., Ga., Ill., Ky.,
Maine, Mass., Md., Mich., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa.,
Tenn., Vt., Va., W.Va.; Europe. This species is easily recognized by
the turgid aspect of the plants with arched, imbricate leaves and with
interruptedly foliate stems, i.e., some regions that appear swollen or
globose as a result of several growth periods. It is only likely to be confused with Dicranum condensatum
(see discussion under that species). 13. Dicranum
brevifolium (Lindberg) Lindberg, Musci Scand.
24. 1879 Dicranum muehlenbeckii var. brevifolium Lindberg, Bot.
Not. 1865: 80. 1865 Plants in dense tufts, light to dark green,
dark brown or sometimes nearly black, dull.
Stems 2–8 cm, densely tomentose
with brown to orange rhizoids nearly to stem apex. Leaves
falcate-secund to erect-spreading, often at wide angles from stems, strongly
crisped when dry, often with a few undulations in distal 1/2,
(3–)5.5–6.5(–8.5) × 0.4–0.8 mm, concave below, keeled above, lanceolate,
acute, margins entire below, serrulate above, incurved in middle of leaf;
laminae 1-stratose or with 2-stratose regions in distal 1/2 of leaf,
especially on margins, sometimes with entire laminae 2-stratose, rarely
margins 3-stratose; costa percurrent or shortly excurrent, 1/6–1/4 width of
leaves at base, very prominent and rounded on abaxial surface, smooth or
slightly rough above on abaxial surface, abaxial ridges lacking, shaped like
a pair of tongs, with 1 row of guide cells, 2 well-developed and thick
stereid bands extending to the apex, adaxial epidermal layer of cells not
differentiated, abaxial layer differentiated; cell walls between lamina cells
strongly bulging; leaf cells smooth to papillose above on abaxial surface;
alar cells 2-stratose, differentiated, sometimes extending to costa; proximal
laminal cells elongate-rectangular, pitted or not pitted, (15–)31–46(–75) ×
(5–)7–9(–12) µm; distal laminal cells short, irregularly
quadrate-rectangular, not pitted, (5–)7–14(–37) × (4)8–9(13) µm. Sexual
condition pseudomonoicous; dwarf males on stem rhizoids of female plants;
interior perichaetial leaves abruptly short-acuminate,
convolute-sheathing. Seta solitary, yellowish to brown,
1.3–3.5 cm. Capsule arcuate, inclined to horizontal, yellowish brown to dark
brown, long-cylindric, 2–4 mm, not or slightly strumose, striate to furrowed
when dry; operculum 1–2.5 mm. Spores 14–30 µm. Capsules mature in summer. Humus or soil over rocks, rarely rotted
wood, exposed to protected bluffs or cliffs, 70–3700 m; Greenland; Alta.,
B.C., Man., Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Yukon; Alaska,
Colo., Mich., Mont., N.Mex., S.Dak.; Europe; Asia. The distinctive leaves are 4–8 mm,
acute, often weakly undulate in the distal part, crisped when dry, standing
out from the stems often at wide angles, concave below, keeled above, the
laminae are often 2-stratose above, especially on margins and near costa,
sometimes entirely 2-stratose with 3-stratose margins (sometimes apparent on
plants at relatively high altitudes in the mountains in Alberta) and the
costa is excurrent, very prominent and conspicuously rounded, especially
noticeable below the leaf middle. The
leaves in cross section are very distinctive, being shaped like a pair of
tongs; abaxial epidermal layer of costal cells is differentiated but no
adaxial epidermal layer cells are enlarged, and the cell walls between the
lamina cells are almost always strongly bulging. Dicranum brevifolium has commonly been confused with
three other species, namely D. muehlenbeckii, D. acutifolium
and D. fuscescens. Dicranum
muehlenbeckii has only 1-stratose leaf laminae and the costae are much
less prominent on the abaxial leaf surface than those of D. brevifolium. A cross section of the distal half of the
leaves of D. muehlenbeckii shows a tubular outline with the cell walls
between the lamina cells smooth and adaxial epidermal layer of costal cells
differentiated, while the leaves of D. brevifolium are tong-shaped in
outline with the cell walls between lamina cells strongly bulging and the
adaxial epidermal layer of costal cells undifferentiated. Dicranum acutifolium differs from D.
brevifolium by its erect-spreading to slightly curled leaves when dry,
instead of crisped leaves standing out from the stems at wide angles, its
costae that are usually moderately distinct and sometimes nearly flat on the
abaxial surface, instead of being prominent and conspicuously rounded, its
V-shaped leaves in cross section, instead of tong-shaped leaves, and its
shorter capsules, 2–2.5 mm, compared to 3–4 mm. Dicranum fuscescens differs from D. brevifolium
by its much less prominent costae on the abaxial leaf surface, by its
V-shaped leaves in cross section, instead of tong-shaped leaves, and by its
weakly bulging cell walls as seen in cross section. The 2- or occasionally 3-stratose leaf
laminae are unusual in the genus Dicranum. The only other species in North America with laminae often
completely 2-stratose in the distal half is D. fulvum. No 3-stratose
leaf laminae have been seen in that species, however. A recently described
species in the section Dicranum, D. crassifolium C. Sérgio, R.
Ochyra & A. Séneca (1995), from Portugal, Spain, and Italy, has
2–3-stratose leaves. It is very unusual
for a species in the type section to have anything but 1-stratose leaves. 14. Dicranum
acutifolium (Lindberg & Arnell) C. E. O. Jensen
in A. H. Weimarck, Foert. Skand. Vaext. Moss. 2: 18. 1937 Dicranum bergeri var. acutifolium Lindberg &
Arnell, K. Svensk. Vet. Ak. Handl. 23(10): 79. 1890 Plants in dense to loose tufts, light green
to light brown, dull. Stems 1.5–7 cm, generally branched
above, somewhat tomentose with reddish brown rhizoids. Leaves
erect-spreading, slightly curled to ± straight when dry, usually with a
few undulations in distal part, (3.5–)5–8(–10) mm × 0.5–1 mm, concave below,
keeled above, sometimes margins ± involute, lanceolate, narrowly acute to
acuminate, margins serrulate to serrate above; laminae 1-stratose or with few
2-stratose regions on or near distal margins; costa percurrent to shortly
excurrent, 1/6–1/4 width of leaves at base, smooth to slightly papillose
above on abaxial surface, abaxial ridges lacking, with a row of guide cells,
2 stereid bands extending to the apex, adaxial epidermal layer of cells not
differentiated, abaxial layer differentiated; cell walls between lamina cells
not or slightly bulging; leaf cells smooth to weakly papillose above on
abaxial surface; alar cells 2-stratose, differentiated, often extending to
costa; proximal laminal cells linear-rectangular, pitted, (22–)41–60(–90) ×
(5–)6–8(–12) µm; distal laminal cells short-rectangular, irregularly angled
or rounded, not pitted, (7–)12–20(–32) × (4–)8–9(–14) µm. Sexual
condition pseudomonoicous; dwarf males on stem rhizoids of female plants;
interior perichaetial leaves abruptly short-acuminate,
convolute-sheathing. Seta solitary, yellow to reddish
yellow, 1.2–2.5 cm. Capsule arcuate, inclined to
horizontal, brown to reddish brown, 2–2.7 mm, furrowed when dry, rarely
slightly strumose; operculum 1.5–2.5 mm.
Spores 14–28 µm. Capsules mature in summer. Somewhat calcareous soils, boulders, rock
outcrops and cliff ledges, sometimes humus, rarely rotten logs; 700–2500 m;
Greenland; Alta., B.C., Man., Nfld. and Labr., N.W.T., Nunavut, Ont., Que.,
Yukon; Alaska, Colo., Maine, Mont., N.H., N.Y., N. Mex., Wyo.; Europe; Asia. This Arctic-alpine species is
recognized by its erect-spreading leaves, slightly curled when dry, keeled
and often weakly undulate above, lanceolate, narrowly acute to acuminate, by
its percurrent to shortly excurrent costae, smooth to slightly papillose
above, and by its leaf cross section that shows only the abaxial row of cells
differentiated, a few 2-stratose marginal cells and the cell walls between
lamina cells smooth to slightly bulging.
Dicranum acutifolium has often been confused with D.
fuscescens but the latter species has a longer, rougher subula that in
leaf cross section in the distal half reveals very large and obvious papillae,
compared to the smaller and less distinct ones in the former, and margins
that are almost completely 2-stratose, while those of D. acutifolium
are mostly 1-stratose. It has also
been confused with D. brevifolium and for distinctions see discussion
under that species. The Colorado record is from W. A. Weber
(1973). The New York, New Mexico, and
Wyoming records are from W. Peterson (1979). 15. Dicranum
fuscescens Turner, Muscol. Hibern. Spic. 60. 1804 Dicranum fuscescens var. congestum (Bridel) Husnot;
D. sulcatum Kindberg Plants light green to dark brownish green,
dull, in loose tufts. Stems 1–6(–18) cm, tomentose to
scarcely tomentose with white or reddish brown rhizoids. Leaves
falcate-secund, often strongly so, sometimes somewhat sparse, distal leaves
curled, proximal leaves with flexuose apices, slightly to strongly curled and
crisped when dry, smooth, (3–)4–7(–10) × 0.6–1 mm, concave below, keeled
above, from a lanceolate base to a gradually narrowed, fine, keeled subula,
margins entire proximally, serrulate to strongly serrate in distal 1/2,
sometimes nearly entire throughout; laminae 1-stratose and usually 2-stratose
above on one or both margins, rarely some 2-stratose regions near costa;
costa excurrent, 1/6–1/4 width of leaves at base, strong, terete, papillose
to spinose distally on abaxial surface, occasionally almost smooth, sometimes
extending to costa, abaxial ridges lacking, with a row of guide cells, 2
well-developed stereid bands extending to distal part of leaf, adaxial epidermal
layer of cells not differentiated, abaxial epidermal layer differentiated;
cell walls between lamina cells slightly bulging; leaf cells smooth to
slightly papillose below on abaxial surface, papillose to spinose prorate
above on abaxial surface; alar cells 2-stratose, strongly differentiated,
sometimes extending to costa; proximal laminal cells elongate, pitted,
(19–)43–62(–93) × (2–)6–8(–12) µm; distal laminal cells irregularly rounded,
elliptic, short-rectangular to quadrate, not pitted, (7–)9–23(–36) ×
(4–)8–12(–14) µm. Sexual condition dioicous; male
plants as large as females, growing intermixed or in separate patches;
interior perichaetial leaves abruptly short-acuminate,
convolute-sheathing. Seta solitary, yellow, reddish
yellow, or brown, 1–3.5 cm. Capsule arcuate, inclined to
horizontal, dark brown to reddish brown, 1–3 mm, strumose, strongly furrowed
when dry, somewhat contracted below mouth; operculum 1–2 mm. Spores
14–24 µm. Varieties ?number worldwide (2 in the
flora): North America, Europe, Asia. l. Plants small, stems 1–6 (–10) cm, usually
densely foliate; leaf margins serrulate to strongly serrate in distal 1/2;
costa papillose to spinose distally on abaxial surface; distal laminal cells
short-rectangular to quadrate, mostly 18–23 μm; seta mostly shorter than2.5
cm.................................................................... 1. Plants large, stems 8–18 cm, sparsely
foliate; leaf margins nearly entire; costa almost smooth on abaxial surface; distal
laminal cells irregularly rounded, elliptic or short- rectangular, mostly
9-19 μm; seta usually 2.5 cm or longer............................................................ 15a. Dicranum
fuscescens Turner var. fuscescens Plants in loose tufts. Stems
1–6 (–10) cm, tomentose with white or reddish brown rhizoids. Leaves
falcate-secund, usually densely foliate, margins serrulate to strongly
serrate in distal 1/2; costa papillose to spinose distally on adaxial
surface; proximal leaf cells elongate, pitted, (25–)43–62(–93) × (2–)6–8(–12)
μm; distal laminal cells short-rectangular to quadrate, not pitted,
(8–)18–23(–31) × (5–)8–12(–14) μm. Seta 1–3.5 cm. Capsules mature in spring. Coniferous or deciduous tree trunks and
bases of trees, rotten logs, stumps, soil, boulders, rock outcrops, cliff
shelves, and humus in woodlands, or sometimes bogs; 10–2300 m; Greenland;
Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont.,
P.E.I., Que., Sask., Yukon; Alaska, Calif., Colo., Ga., Idaho, Ky., Maine,
Mass., Mich., Minn., Mont., N.H., N.Mex., N.Y., N.C., Ohio, Oreg., Pa.,
S.Dak., Tenn., Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; Asia. The var. fuscescens is highly
variable but is best known by the loose tufts of green to brownish green,
dull plants, the slender, falcate-secund leaves ending in a slender, keeled
subula, slightly to strongly crisped when dry, the strongly serrated, often
2-stratose distal leaf margins, the excurrent costa that is conspicously
rough above with papillae and spines on the abaxial surface, the nonpitted,
short-rectangular, quadrate or irregularly angled distal leaf cells, and the
solitary, often strumose, capsules that are inclined to horizontal. Some plants of D. fuscescens,
especially those in the northern part of Canada, may be confused with D.
acutifolium. The latter, however,
usually has a few undulations on the leaves and the leaf cross section often
reveals larger, more rounded bulging cell walls between the lamina cells and
fewer 2-stratose regions on the margins than D. fuscescens. Dicranum sulcatum Kindberg, considered a synonym here
and by R. S. Williams (1913), has been recognized by W. Peterson (1979) as a
distinct species. The diagnostic
features are duller color due to a greater degree of papillosity,
long-excurrent costa, wider costa at mid-leaf, and presence of more rows of
stereid cells, 3–5 rows compared to 2–3 rows in D. fuscescens. Dicranum sulcatum is reported to
occur usually on living coniferous trees in the Pacific Northwest, from
southern Alaska south to central California, inland to northern Idaho and
northwestern Montana. All of the
diagnostic characters are too variable to be important in maintaining this
species. Furthermore, they are all
quantitative characters, which makes it difficult to establish a distinct
species without at least one good qualitative character. Further studies could help to establish it
as a variety. The Kentucky record is from J. A.
Snider et al. (1988), the
Massachussetts record is from F. J. Hilferty (1960), and Ohio record is from
J. A. Snider and B. K. Andreas (1996). 15b. Dicranum
fuscescens var. flexicaule (Bridel) Wilson, Bryol. Brit. 77. 1855 Dicranum flexicaule Bridel, Bryol. Univ. 1: 421. 1826 Plants in loose tufts. Stems
8-18 cm, scarcely tomentose. Leaves strongly falcate-secund,
somewhat sparse, margins nearly entire; costa almost smooth on abaxial
surface; proximal laminal cells elongate, (19–)42–54(–84) × (5–)7–9(–12) µm;
distal laminal cells irregularly rounded, elliptic or short-rectangular,
(7–)9–19(–36) × (4–)8–9(–13) µm. Seta 2.5–3.5 cm. Capsules mature in summer. Moist humus banks, humus on coniferous
forest floors, and bogs on small conifers (often black spruce); 900–1300 m;
B.C., N.W.T., Que., Yukon; Europe. This is an Arctic-alpine variety that
needs further collecting and study to determine its taxonomic status. J.
Kucyniak (D. Löve et al. 1958) called attention to it in the Quebec bryoflora
(G. Bellolio-Trucco and R. R. Ireland 1990) and, many European bryologists
recognize it as a form (W. Mönkemeyer 1927), variety (J. Podpêra 1954; L. I.
Savich-Lyubitskaya and Z. N. Smirnova 1970; V. M. Melnichuk 1970) or species
(E. Nyholm 1986). It is immediately
noticed because of the large size of the plants whose stems are up to 18 cm,
sparsely foliated with strongly falcate-secund leaves, and the long seta,
2.5–3.5 cm. It is further recognized
microscopically by the irregular shape of the distal leaf cells, the nearly
entire leaf margins, and the costa almost smooth on the abaxial surface. 16. Dicranum
pallidisetum (J. W. Bailey) Ireland, Bryologist 68:
446. 1965 Dicranum fuscescens f. pallidiseta J. W. Bailey in
Holzinger, Musci Acro. Bor.-Amer. & Eur. 653. 1929 Plants in loose tufts, dark green to
yellowish green, dull to glossy. Stems 1–6 cm, tomentose with white or
reddish brown rhizoids. Leaves often secund, straight or
nearly so, often crisped when dry, smooth, 4–8 × 0.5–1 mm, lanceolate, acute,
tubulose to apex, margins entire below, serrulate ot serrate near apex;
laminae 1-stratose or sometimes 2-stratose on distal margins; costa
excurrent, 1/5–1/3 width of leaves at base, abaxially papillose or toothed
from leaf middle to apex, abaxial ridges lacking. with a row of guide cells,
stereid bands often present and well developed in proximal part of leaf,
lacking in distal 1/4–1/3 of leaf, cells above and below guide cells large
and thin walled; cell walls between lamina cells not or slightly bulging;
leaf cells smooth or often strongly papillose in distal 1/2 of leaf; alar
cells 2-stratose, differentiated, often extending to costa, abaxial ridges
lacking; proximal laminal cells linear to rectangular, with or without pits,
(26–)58–95(–130) × (10–)12–14(–16) µm; distal laminal cells quadrate,
rounded, irregularly angled or short-rectangular, not pitted, (10–)15–26(–38)
× (8–)9–11(–12) $$$m. Sexual condition dioicous; male
plants as large as female plants; interior perichaetial leaves abruptly
short-acuminate, convolute-sheathing.
Seta solitary or sometimes
2, rarely 3 per perichaetium, yellow, rarely reddish yellow or brown with
age, 1–2.5 cm. Capsule arcuate, inclined, often with a small struma, yellow or
yellowish brown, rarely reddish yellow or brown with age, 1.5–3.5 mm,
strongly furrowed when dry, contracted below mouth; operculum 1.5–2.5
mm. Spores 14–20 µm. Capsules mature in summer. Humus or soil over rocks, rarely rotting
logs or decayed wood; 500–2000 m; Alta., B.C.; Alaska, Idaho, Mont., Oreg.,
Wash. This is an endemic northwestern North
American species that has often been confused with Dicranum fuscescens,
being considered a form of it for many years (R. R. Ireland 1966). Unlike that species, which often occurs at
low altitudes below 800 m, D. pallidisetum occurs predominately at
high elevations, 800–2000 m, rarely being found as low as 500 m. It is
distinguished from D. fuscescens by its tubulose leaves, usually
1-stratose or rarely 2-stratose on the margins, by its costa cross section
that shows no stereid bands in distal 1/3 of the leaf, and by its yellow or
yellow-brown capsules that are sometimes 2–3 per perichaetium. In contrast, D. fuscescens has
leaves keeled above, usually 2-stratose on both margins, rarely 1-stratose on
one margin, stereid bands present throughout the leaf and dark brown to
reddish brown capsules that are solitary or rarely 2 per perichaetium. 17. Dicranum
spadiceum J. E. Zetterstedt, K. Svensk. Ak. Handl.
5(10): 20. 1865 Dicranum angustum Lindberg; D. laevidens R. S.
Williams Plants in loose to dense tufts, green to
yellowish green or brown, glossy. Stems 2.5–7 cm, densely tomentose
with reddish brown rhizoids. Leaves straight, erect-spreading,
little changed when dry, smooth, (4–)5.5–8(–9) × 0.5–1 mm, concave below,
tubulose above, from a lanceolate base to a long-acuminate subula, apices acute
or sometimes ± blunt, margins entire or slightly serrate in distal 1/3;
laminae 1-stratose; costa percurrent to shortly excurrent, 1/10–1/6 width of
leaves at base, smooth to slightly rough above on abaxial surface, abaxial
ridges lacking, with a row of guide cells, 2 well-developed stereid bands
extending almost to apex, abaxial epidermal layer of cells differentiated,
rarely some cells in adaxial epidermal layer enlarged; cell walls between
lamina cells not or slightly bulging; leaf cells smooth; alar cells
2-stratose, well differentiated, not extending to costa; proximal laminal
cells elongate, pitted, (16–)36–62(–112) × (3–)7–8(–20) µm; distal laminal
cells short-rectangular to irregularly angled, pitted, (9–)10–17(–31) ×
(3–)7–8(–18) µm. Sexual condition pseudomonoicous; dwarf males on rhizoids of
female plants; interior perichaetial leaves abruptly acuminate,
convolute-sheathing. Seta solitary, rarely 2 per
perichaetium, yellow to reddish yellow, 2.5–3.5 cm. Capsule arcuate,
inclined, light to dark brown, 2–3.5 mm, furrowed when dry; operculum 1.5–2.8
mm. Spores 14–22 µm. Capsules mature in summer. Fens, wet meadows, willow thickets, or
humus or soil on or around rocks at lake margins, occasionally drier
habitats, such as beach ridges; 10–2300 m; Greenland; Alta., B.C., Man.,
Nfld. and Labr., Nunavut, Ont., Que., Sask., Yukon; Alaska, Colo., Mont.,
Utah, Wyo.; Europe; Asia. This is an Arctic-alpine species known
principally by the 4–9 mm, straight, erect-spreading leaves, scarcely changed
when dry, concave below, tubulose above, narrowed from a lanceolate base to a
long-acuminate subula ending in an acute to ± blunt apex; the elongate,
pitted cells throughout the leaf; and the costa that is smooth to somewhat
rough above on the abaxial surface. Dicranum angustum Lindberg, often considered distinct
because of its blunt leaf apices, is considered a synonym after examination
of its type from Europe (see discussion by G. Bellolio-Trucco and R. R.
Ireland 1990). The Saskatoon record is from G. Bellolio-Trucco
and R. R. Ireland (1990), the Colorado record is from W. Peterson (1979),
Montana record is from S. Eversman and A. J. Sharp (1980), and the Utah
record is from S. Flowers (1973). 18. Dicranum
muehlenbeckii Bruch, Schimper & W. Gümbel, Bryol.
Eur. 1: 142. 78. 1847 (fasc. 37-40.
Mon. 38.30) Plants in dense tufts, green to yellowish
green, dull. Stems 3–7 cm, densely tomentose with reddish brown rhizoids.
Leaves erect-spreading, strongly cirrate to crisped when dry,
smooth, (4–)5–6.5(–8) × 0.5–1 mm, concave below, tubulose above, lanceolate,
acute, margins entire below, slightly serrate to entire above; laminae
1-stratose; costa excurrent, 1/6–1/4 width of leaves at base, smooth or
weakly toothed above on abaxial surface, abaxial ridges lacking, with a row
of guide cells, 2 stereid bands extending to apex, adaxial and abaxial
epidermal layers of cells differentiated; cell walls between lamina cells
slightly bulging; leaf cells smooth to slightly rough above on abaxial
surface; alar cells 2-stratose, differentiated, sometimes extending to costa;
proximal laminal cells rectangular, pitted, (19–)37–55(–73) × (5–)9–12(–14)
µm; distal laminal cells short, irregularly quadrate-rectangular, not pitted,
(7–)11–12(–23) × (6–)8–9(–13) µm. Sexual condition pseudomonoicous;
dwarf males on stem rhizoids of female plants; interior perichaetial leaves
abruptly short-acuminate, convolute-sheathing. Seta solitary,
yellowish to yellowish brown, 1.3–3 cm.
Capsule arcuate and
inclined to ± straight and nearly erect, yellowish brown, long-cylindric, 2–4
mm, smooth, striate when dry; operculum 1.5–2.5 mm. Spores 14–24 µm. Capsules mature in summer. Humus and sandy soil on cliffs, bluffs,
often over boulders and among rocks in open woods or exposed sites; 10–3100 m;
Greenland; Alta, B.C., Man., N.B., Nfld. and Labr., N.W.T., Nunavut, Ont.,
Que., Yukon; Alaska, Colo., Mass., Mont., Nebr., N.J., N.Mex., N.Y., N.Dak.,
S.Dak., Vt., Wyo.; Europe; Asia. This is a somewhat rare species
throughout North America where it is often misidentified as other species of Dicranum. There should be no reason for its
misidentification if its important characters are utilized for
recognition. Smooth, erect-spreading
leaves, cirrate to crisped when dry and tubulose above, smooth leaf cells,
1-stratose laminae, and cross section of the costa showing the abaxial and
adaxial rows of cells differentiated, all combine to make the gametophytes
different from all other North American species of the genus. Sporophytes are rarely produced but the
2–4 mm, solitary, long-cylindric, slightly strumose capsules, which are
suberect to slightly arcuate and weakly striate when dry, are distinctive. 19. Dicranum
elongatum Schwägrichen, Spec. Musc. Suppl. 1(1):
171. 1811 Plants
in compact tufts,
yellowish green to light green, glossy.
Stems 2–10 cm, tomentose
throughout with reddish brown rhizoids.
Leaves erect-spreading,
erect-appressed to rarely spreading when dry, apex sometimes flexuose,
smooth, (2.5–)3–4.5(–6) × 0.3–0.5 mm, from a lanceolate base to a long, fine,
tubulose subula, apex usually acute, sometimes apical leaves of stems blunt,
julaceous, margins entire, rarely slightly denticulate at apex; laminae
1-stratose; costa percurrent or shortly excurrent, 1/6–1/4 width of leaves at
base, smooth or weakly rough above on abaxial surface, abaxial ridges
lacking, with a row of guide cells, 2 stereid bands not extending to apex,
adaxial and abaxial epidermal layers of cells usually not differentiated or
sometimes a few cells in both layers enlarged; cell walls between lamina
cells slightly bulging; leaf cells smooth; alar cells 1-stratose or
2-stratose, well differentiated, not extending to costa; proximal laminal
cells usually elongate, pitted, (14–)24–36(–49) × (2–)4–6(–9) µm; distal
laminal cells short-rectangular, quadrate, rounded, or sometimes irregularly
shaped, incrassate, not pitted, (5–)12–17(–23) × (4–)6–8(–9) µm. Sexual
condition dioicous; male plants as large as females; interior
perichaetial leaves abruptly short-acuminate, convolute-sheathing. Seta solitary, yellowish to yellowish brown or
reddish yellow, 1.5–2 cm. Capsule nearly straight and erect to
slightly arcuate, yellowish brown, 1.2–1.8 mm, striate when dry; operculum
1.2–1.8 mm. Spores 17–22 µm. Capsules mature in summer. Common in arctic or alpine tundra, soil,
rocks or soil over rocks, rock ledges, cliff shelves, rarely decayed wood and
stumps, sometimes in bogs and fens; 30–3700 m; Greenland; Alta., B.C., Man.,
Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon; Alaska,
Colo., Maine, Minn., Mont., N.H., N.Y.; Europe; Asia. This is an Arctic-alpine species that
is easy to recognize because the plants are relatively small, slender, glossy
and grow in dense, compact tufts. The
leaves are short, narrow, usually less than 6 ´ 0.5 mm, ending in a long, fine, tubulose subula, acute at
the apex, smooth or nearly so on the abaxial surface, and have entire margins
or rarely some denticulations at the apex.
Capsules, which are not uncommon on plants in some Arctic localities,
are short, less than 2 mm, straight and erect to slightly arcuate, smooth but
striate when dry. Dicranum elongatum can readily be confused with a closely
related species D. groenlandicum.
They both are Arctic-alpine species sharing nearly the same type of
habitat with almost the same distribution.
They can usually be readily distinguished in their typical form but
there appear to be many intergradations that cause difficulty. Dicranum groenlandicum has narrowly
obtuse leaf apices and cells that are pitted to well above the middle of the
leaf in contrast to the acute leaf apices and cells that are pitted only up
to the middle of the leaf in D. elongatum. E. Hegewald (1972) found that the pits in the leaf are the most
reliable means of separating difficult specimens of Finnish plants. H. A. Crum and L. E. Anderson (1981) have
expressed doubt as to whether the two are genetically different. Both D. elongatum and D.
groenlandicum often bear at the apex of some stems julaceous shoots with
small, ovate, broad leaves with obtuse apices. This can lead to the misidentification of some plants of D.
elongatum unless the leaves in the basal part of the stems are always
used to determine the shape of the leaf apices. 20. Dicranum
groenlandicum Bridel, Mant. Musc. 4: 68. 1819 Plants in dense tufts, light green,
glossy. Stems 4.5–10 cm, tomentose throughout with brown to red
rhizoids. Leaves erect-spreading, erect-appressed when dry, smooth,
(2.5–)3–4(–6.5) × 0.3–0.5 mm, from an ovate-lanceolate base to a tubulose
subula, narrowly obtuse at apex, rarely acute, sometimes apical leaves of
stems julaceous, margins entire; laminae 1-stratose, occasional 2-stratose
regions near costa in proximal part of leaf; costa subpercurrent to percurrent,
1/10–1/6 width of leaves at base, smooth, abaxial ridges lacking, with a row
of guide cells, 2 well-developed and thick stereid bands (5–6 cells thick),
adaxial epidermal layer of cells not differentiated, abaxial layer usually
with a few cells enlarged; cell walls between lamina cells slightly bulging;
leaf cells smooth; alar cells 1- or 2-stratose, well-differentiated, not
extending to costa; proximal laminal cells elongate-sinuose, strongly pitted,
(36–)54–65(–98) × (2–)5–6(–9) µm; distal laminal cells (11–)17–26(–42) ×
(2–)5–6(–12) µm. Sexual condition dioicous; male plants as large as females;
interior perichaetial leaves abruptly short-acuminate,
convolute-sheathing. Seta solitary, yellow to reddish
yellow, 1.5–2 cm. Capsule nearly straight and erect to
slightly arcuate, yellowish brown, 1.5–2 mm, ± striate when dry; operculum
1–1.7 mm. Spores 14–19 µm. Capsules mature in summer. Arctic or alpine tundra, soil, humus or
rocks, sometimes in bogs and fens; 10–3800 m; Greenland; Alta., B.C., Man.
Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Yukon; Alaska, Colo., N.Y.;
Europe; Asia. This Arctic-alpine species is sometimes
not a very distinct species, often being difficult to separate from its
nearest relative, D. elongatum. For distinctions see the discussion
under that species. 21. Dicranum
fragilifolium Lindberg, Bot. Not. 1857: 146. 1857 Plants
in compact tufts,
light green to yellowish brown, glossy.
Stems 1.5–6 cm, densely
tomentose with dark brown to red rhizoids.
Leaves straight,
erect-spreading, rigid, appressed when dry, smooth, (5–)6–7(–7.5) × 0.4–0.6
mm, most of the leaf tips deciduous and lacking, concave below, canaliculate
above, from a lanceolate base to a long subula formed by excurrent costa,
apex acute, margins entire to somewhat serrulate above; laminae 1-stratose or
some 2-stratose regions near costa; costa excurrent, 1/4–1/3 width of leaves
at base, smooth or slightly rough above on abaxial surface, abaxial ridges
lacking, with a row of guide cells, 2 thin stereid bands (2–3 cells thick),
adaxial and abaxial epidermal layers not differentiated or sometimes with a
few cells in both layers enlarged; cell walls between lamina cells slightly
bulging; leaf cells smooth; alar cells 1-stratose, sometimes with some 2-stratose
regions, well differentiated, sometimes extending to costa; proximal laminal
cells elongate-rectangular, usually pitted or indistinctly pitted,
(25–)39–55(–84) × (5–)7–8(–10) µm; median laminal cells rectangular, not
pitted, (11–)21–22(–37) × (4–)7–8(–10) µm; distal laminal cells nearly
elliptic, incrassate. Sexual condition dioicous; male
plants as tall as females, usually more slender; interior perichaetial leaves
abruptly long-acuminate, convolute-sheathing. Seta solitary,
yellowish to brown, 1.5–2.5 cm. Capsule arcuate to nearly straight, ±
erect, yellowish brown, 1.8–2 mm, smooth, sometimes striate when dry;
operculum 1–2 mm. Spores 16–28 µm. Capsules mature in summer. Rotten logs and stumps, humic soil, humus
over rocks, usually in coniferous woods, occasionally in mixed woods and
bogs; 30–1900 m; Greenland; Alta., B.C., Man., Nfld. and Labr., N.W.T., Ont.,
Que., Sask.,Yukon; Alaska, Mich.; Europe; Asia. This is a rare boreal species with
shiny, light green to yellowish brown, erect-spreading leaves. The distal portion of the leaves is
fragile and often broken off, thereby giving the plants a distinctive
appearance. The deciduous leaf apices
presumably serve as a type of asexual reproduction by regenerating to produce
new plants. The species is often
confused with D. tauricum, another species with deciduous leaf tips,
but D. tauricum occurs only in western North America. Where their
ranges overlap they frequently are difficult to tell apart. When sporophytes are present the straight
capsules of D. tauricum are distinctive from the usually arcuate ones
of D. fragilifolium, which unfortunately rarely produces them. When sterile, the best way to separate the
two is by the costa cross section in the proximal half of the leaf: Dicranum fragilifolium has stereid
cells in two thin bands while D. tauricum has none. Also, in Dicranum fragilifolium
there are 2–3 layers of cells above and below the guide cells, while in D.
tauricum there are 1 or rarely 2 layers of cells. One other species with deciduous leaf tips
that has sometimes been confused with D. fragilifolium is D. viride
of eastern North America. It has a
straight capsule like D. tauricum but as in D. fragilifolium
capsules are rarely produced. The
broad costa of D. viride, covering one third or more of the leaf base,
will distinguish it from D. fragilifolium, the costa of which
covers one fourth or less of the leaf base. 22. Dicranum
fulvum Hooker, Musci Exot. 2: 149. 1819 Plants in loose tufts, dark green above,
blackish green below, dull. Stems 1.5–3.5 cm, sparsely tomentose
with light- to reddish-brown rhizoids.
Leaves erect-spreading,
some weakly falcate-secund, crisped when dry, smooth, (3–)4–5(–7) × 0.5–0.8
mm, some leaf tips broken off, concave below, subtubulose above, narrowly
lanceolate to a long, narrow subula occupied mainly by the excurrent costa,
apex acute, margins serrate to serrulate in distal 1/2; laminae 1- or
2-stratose above, sometimes 2-stratose in patches; costa excurrent, 1/4–1/3
width of leaves at base, abaxially toothed or papillose in distal 1/2,
abaxial ridges lacking, with a row of guide cells, 2 stereid bands not
extending above leaf middle, adaxial and abaxial epidermal layers of cells
somewhat differentiated or with a few cells enlarged in both layers, cell
walls between lamina cells strongly bulging in distal part of leaf lamina;
leaf cells smooth or abaxially prorate above; alar cells mostly 1-stratose or
sometimes with a few 2-stratose cells, distinctly differentiated, often
extending to costa; proximal laminal cells elongate-rectangular, not pitted
or with few pits, (19–)24–33(–42) × (4–)5–6(–9) µm; distal laminal cells
regularly quadrate to short-rectangular, not pitted, (5–)10–11(–16) ×
(4)5–6(9) µm. Sexual condition dioicous; male plants as tall as female plants
but usually more slender; interior perichaetial leaves abruptly
long-acuminate, convolute-sheathing. Seta solitary, brown or reddish
brown, 1–2 cm. Capsule straight and erect, reddish brown, 1.5–3 mm, smooth,
slightly furrowed when dry; operculum 1.5–2 mm. Spores 14–28 µm. Capsules mature in spring. Sandstone, limestone or acidic rock
outcrops, bluffs, cliff faces, and boulders in deciduous woodlands,
especially along streams; rarely on bases of tree trunks, fallen trees and
logs; 200–1900 m; N.B., N.S., Ont., Que.; Ala, Ark., Conn., D.C., Ga., Ill.,
Ind., Iowa , Ky., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J.,
N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.;
Europe; Asia. This eastern North American species,
occurring primarily on rock, has dull, blackish green plants, especially
evident from the leaves on the basal part of the stems, crisped leaves when
dry, broad costae that cover 1/4–1/3 the width of the leaves at base, laminae
that are mostly 2-stratose in the distal half of the leaf, and erect,
cylindrical capsules that are slightly furrowed when dry. The species is sometimes confused with Dicranum
fuscescens but that species has keeled leaves in the distal half, with
2-stratose regions restricted to the margins, and horizontal capsules,
whereas D. fulvum has subtubulose leaves, with almost entirely
2-stratose laminae above, and erect capsules. When D. fulvum has some of its leaf apices broken off,
which is not uncommon, it can be confused with D. viride, which has
the majority of its leaf tips lacking.
The usual occurrence on rock of plants of D. fulvum as opposed
to the usual occurrence on bases of tree trunks of D. viride often
gives some clue to their identity. Morphologically, the proximal leaf cells
of the two differ: D. fulvum
has shorter cells, averaging 24–33 µm, compared to the longer cells of D.
viride, averaging 33–42 µm. 23. Dicranum
viride (Sullivant & Lesquereux) Lindberg,
Hedwigia 2: 70. 1863 Campylopus viridis Sullivant & Lesquereux, Musc. Bor.
Amer. 18. 1856; Dicranum fulvum subsp. viride (Sullivant
& Lesquereux) Lindberg; D fulvum var. viride (Sullivant
& Lesquereux) Frye Plants in loose to dense tufts, yellowish to
dark green, glossy to dull. Stems 1.5–4.5 cm, sparsely tomentose
with whitish to reddish brown rhizoids.
Leaves erect-spreading or
somewhat falcate-secund, rigid, erect below and flexuose above when dry,
smooth, (3–)4–6(–7) × 0.5–0.8 mm, most of the leaf tips broken off, concave below
to canaliculate above, from a lanceolate base to a long-acuminate, acute apex
(when present), margins entire, sometimes slightly denticulate at apex;
laminae 1-stratose or with some 2-stratose regions in patches between margin
and costa; costa excurrent, 1/5–1/4 width of leaves at base, smooth or
slightly rough on abaxial surface in distal 1/2, abaxial ridges lacking, with
a row of guide cells, 2 weakly developed stereid bands above and below, not
extending above leaf middle, adaxial and abaxial epidermal layers of cells
not differentiated or with a few cells enlarged in both layers; cell walls
between lamina cells not or weakly bulging; leaf cells usually smooth; alar
cells 1-stratose or with a few 2-stratose regions, well-differentiated, often
extending to costa; proximal laminal cells rectangular to short-rectangular,
not pitted or with few pits, (11–)33–42(–51) × (7–)9–10(–13) µm; median
laminal cells regularly quadrate, not pitted, (9–)15–22(–26) × (5–)7–8(–11)
µm; distal laminal cells small, quadrate, not pitted. Sexual
condition dioicous; male plants as large as females; interior
perichaetial leaves abruptly long-acuminate, convolute-sheathing. Seta
solitary, yellow to reddish brown, 1–1.6 cm.
Capsule straight, erect,
brown to reddish brown, 1.5–2.5 mm, smooth, slightly furrowed when dry;
operculum 1–1.5 mm. Spores 9–22 µm. Capsules mature in spring. ommonly
growing on the base of trees (usually deciduous but sometimes coniferous,
especially Thuja), rotten logs, stumps, rarely soil and acidic or
limestone rocks; 40–1400 m; N.B., N.S., Ont., P.E.I., Que.; Alaska, Ill.,
Ind., Iowa, Ky., Maine , Md., Mass., Mich., Minn., N.H., N.Y., N.C., Ohio,
Pa., Tenn., Vt., Va., W.Va., Wis.; Europe; Asia. This is not an uncommon species of the
eastern United States and southeastern Canada. It rarely produces sporophytes
and is a distinctive species because of the fragile, deciduous leaf tips,
which probably serve as a means of asexual reproduction. It has on occasion been confused with Dicranum
fulvum, which has nearly the same distribution, and rarely with D.
fragilifolium where their ranges overlap in the Great Lakes region. For distinctions see the discussion under
those species. The Alaska record is from I. A. Worley
and Z. Iwatuski (1970), and the Kentucky record is from Smider et al. (1988). 24. Dicranum
tauricum Sapjegin, Bot. Jahrb. 46 (Beibl. 105):
10. 1911 Dicranum strictum D. Mohr Plants in dense tufts, light green to
yellowish green, glossy. Stems 0.5–3 cm, tomentose below with whitish
or reddish brown rhizoids. Leaves straight, erect-spreading,
little changed when dry, smooth, 4–6 × 0.2–0.4 mm, most of the leaf tips
deciduous and lacking, lanceolate, concave below, tubulose above, apex acute,
margins entire or serrulate at apex; laminae 1-stratose or with 2-stratose
regions near apex; costa long-excurrent, 1/6–1/4 width of leaves at base,
abaxial ridges lacking; leaf cells smooth, guide cells, no stereid bands, 1
or 2 rows of cells above and below guide cells with slightly thickened walls
and large lumens, the adaxial and abaxial epidermal layers of cells not
differentiated; cell walls between lamina cells not bulging; alar cells
1-stratose, differentiated, not extending to costa; proximal laminal cells
rectangular to linear, with a few pits, (46–)60–105(–120) × (4–)6–16(–22) µm;
distal laminal cells quadrate, rounded or short-rectangular, not pitted,
(12–)17–25(–32) × (8–)10–11(–12) µm. Sexual condition dioicous; male
plants as large as females; interior perichaetial leaves gradually narrowed
to a subulate apex, convolute-sheathing.
Seta solitary, yellow to
light brown, 1.5–2.5 cm. Capsule straight and erect, yellow to
light brown, 1.4–2.5 mm, smooth, often irregularly wrinkled when dry;
operculum 1–1.8 mm. Spores 10–18 µm. Capsules mature in summer. Frequently on rotten logs, stumps, or tree
bases in woodlands, sometimes on humus or humus over rocks; 100–2200 m;
Alta., B.C., N.W.T., Sask.; Alaska, Calif., Colo., Idaho, Mont., nw Nebr.,
Oreg., S.Dak., Utah, Wash., Wyo.; Europe. Dicranum tauricum is a western North American species,
occurring primarily on trees and rotten wood. It is recognized as glossy
plants with broken off leaf tips and straight, erect capsules. It can be confused with D.
fragilifolium which also has broken off leaf tips and whose range
overlaps with D. tauricum. For distinctions see discussion under D.
fragilifolium. The Utah record is from S. Flowers
(1973). 25. Dicranum
montanum Hedwig, Spec. Musc. 143. 1801 Plants in dense tufts, usually with weak, clustered
branchlets near stem apices with small, linear, erect-spreading, costate
leaves, strongly crisped when dry, yellowish green to dark green, dull,. Stems
0.5–3(–5) cm, densely tomentose with white to reddish brown rhizoids. Leaves
erect-spreading, cirrate to strongly crisped when dry, smooth, (1–)2–3(–4) ×
0.2–0.5 mm, concave below, subtubulose to keeled above, lanceolate at base,
acuminate above to an acute apex, rough above on abaxial surface, margins
irregularly serrate to serrulate in distal 1/2 of leaves; laminae 1-stratose;
costa percurrent to shortly excurrent, 1/6–1/4 width of leaves at base, rough
with papillae or teeth on abaxial surface in distal 1/2 of leaf, abaxial
ridges lacking, with a row of guide cells, 2 weakly developed stereid bands
above and below, not extending to leaf middle, adaxial and abaxial epidermal
layers of cells not differentiated or with a few cells enlarged in both
layers; cell walls between lamina cells not bulging; leaf cells smooth below,
mammillose or usually abaxially prorate or toothed in distal 1/2 of leaves,
giving leaves a dull appearance; alar cells 1-stratose, differentiated or
sometimes indistinctly differentiated, not extending to costa; proximal
laminal cells rectangular to oblong-rectangular, not pitted or with few pits,
(10–)20–32(–50) × (4–)6–8(–13) µm; distal laminal cells usually quadrate to
short-rectangular, some cells transversely elongate, not pitted,
(5–)8–10(–26) × (2)3–6(9) µm. Sexual condition dioicous; male
plants as large as females; interior perichaetial leaves abruptly acuminate,
convolute-sheathing. Seta solitary, rarely 2 per
perichaetium, yellowish to reddish brown, 0.5–1.5 cm. Capsule
straight and erect to slightly inclined, rarely somewhat arcuate, light
yellowish brown, 1.2–2 mm, smooth, striate when dry; operculum 1–1.5 mm. Spores
12–24 µm. Capsules mature in spring. Rotting stumps and logs, tree bases
(usually deciduous trees), occasionally soil or humus over rocks, especially
boulders and cliff ledges, in dry to mesic woods, rarely swamps; 0–2800 m;
B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que.,
Sask.; Alaska, Ariz, Ark., D.C., Ill., Ind., Iowa, Ky., Maine, Md., Mass.,
Mich., Minn., Mo., Nebr., N.H., N.Mex., N.Y., N.C., Ohio, Okla., Pa., Tenn.,
Vt., Va., W.Va., Wis.; Europe; Asia. This is one of the smallest species of
the genus in North America. It can
best be recognized by the small plants, often only 1–2 cm, the dull,
yellowish green to dark green leaves that are strongly crisped when dry, the
lanceolate, acuminate leaves that are subtubulose to keeled above, rough on
the abaxial surface near the apex, and the straight, erect capsules. Also aiding in its recognition are the
occasional presence of small, delicate, clustered branchlets with linear
leaves that are readily detachable (probably a means of asexual
reproduction), which occur near the stem apices. The detached leaves from the branchlets leave characteristic
scars on the denuded portions. Dicranum
montanum can sometimes be mistaken for D. flagellare, its closest
relative, especially when the latter species does not have its typical
flagelliform branchlets in the leaf axils or when they have been overlooked. Dicranum montanum has leaves with a keeled subula in the
distal half, with a strongly papillose or toothed abaxial surface near the
apex and distal leaf cells that are regularly quadrate. Dicranum
flagellare, in contrast, has leaves with a tubulose subula above, with
the abaxial surface usually smooth, and mostly short-rectangular leaf cells. 26. Dicranum
flagellare Hedwig, Spec. Musc. 130. 1801 Dicranum flagellare var. minutissimum Grout Plants in dense tufts, usually bearing 2–6
dark green, stout, terete branchlets, 1–4 mm, in the axils of distal leaves,
each flagelliform branchlet with short, ovate to lingulate, broadly acute to
obtuse, ecostate or shortly and indistinctly costate leaves closely appressed
to the axis, yellowish green to dark green, glossy. Stems 0.5–6 cm,
densely tomentose with light brown to reddish brown rhizoids. Leaves
falcate-secund to nearly straight, crisped to weakly crisped when dry,
smooth, (1–)2–4(–5) × 0.3–0.6 mm, concave below, tubulose above, from a
lanceolate or ovate-lanceolate base to an acuminate subula, apex acute,
margins smooth to serrulate above; laminae 1-stratose; costa percurrent or
sometimes ending just before apex, 1/6–1/4 width of leaves at base, smooth to
± rough with papillae or small teeth on abaxial surface near apex of leaf,
abaxial ridges lacking, with a row of guide cells, 2 stereid bands above and
below not extending above leaf middle, adaxial epidermal layer of cells not
differentiated, abaxial layer with some cells differentiated; cell walls
between lamina cells not bulging; leaf cells smooth or weakly abaxially
prorate above; alar cells 1-stratose, distinctly differentiated, not
extending to costa; proximal laminal cells elongate-rectangular, not pitted
or with few pits, (12–)24–38(–70) × (4–)10–15(–18) µm; distal laminal cells
short-rectangular to quadrate, not pitted, (5–)12–14(–23) × (5–)7–12(–14)
µm. Sexual condition dioicous; male plants as large as females;
interior perichaetial leaves abruptly long-acuminate,
convolute-sheathing. Seta solitary, yellowish to brown,
1–2.5 cm. Capsule straight and erect or nearly so, yellowish brown to
brown, 1.5–3 mm, striate when dry; operculum 0.5–l.6 mm. Spores
12–19 µm. Capsules mature in spring. Rotting wood, especially stumps and logs,
base of trees, exposed tree roots, soil or humus over boulders usually in
mesic woods, sometimes swamps and bogs; 0–1300 m; Alta., B.C., Man., N.B.,
Nfld. and Labr., N.W.T., N.S., Ont., P.E.I., Que., Sask.; Ala., Ariz., Ark.,
Colo., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Ky., La., Maine, Md., Mass.,
Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla.,
Pa., R.I., S.C., S.Dak., Tenn., Vt., Va., W.Va., Wis.; Mexico (Chihuahua,
Coahuila, Durango, Jalisco, Nuevo León, Tamaulipas); West Indies; Central
America (Costa Rica, Guatemala, Panama); Europe; Asia. Dicranum flagellare is easily recognized because of the
presence of unique axillary, flagelliform branchlets, in clusters of 2–6,
which almost always some plants in each colony possess. The branchlets are deciduous and represent
another type of asexual reproduction present in species of Dicranum,
e.g., deciduous branchlets with linear, crisped leaves in D. montanum,
and deciduous leaf tips in D. fragilifolium, D. tauricum and D.
viride. C. Correns (1899)
discusses the flagelliform branchlet type of asexual reproductive in D.
flagellare as well as the other types of asexual reproduction occurring
in the genus. The only species likely
to be confused with D. flagellare if the flagelliform branchlets are
overlooked or cannot be found is D. montanum. For distinctions see the discussion under
that species. The Northwest Territory record is from
W. Peterson (1979), and the Arizona record is from I. M. Haring (1961). Excluded species: Dicranum arcticum
Schimper, Musci Eur. Nov. Bryol. Eur. Suppl. fasc. 3-4 Mon. Dicranum
3.3. 1866 = Kiaeria glacialis
(Berggren) I. Hagen, K. Norsk. Vid. Selsk. Skrift. 1914 (1): 125. 1915 (Dicranum glaciale Berggren, Lunds
Univ. Års-skr. Afd. Math. Nat. 2(7): 19. 1-9. 1866). Dicranum longifolium
Hedwig, Spec. Musc.130. 1801 =
Paraleucobryum longifolium
(Hedwig) Loeske, Hedwigia 47: 171.
1908. Dicranum subporodictyum (Brotherus) C. H. Gao & T. Cao,
Bryobrothera 1: 218. 1992 (Dicranodontium subporodictyon
Brotherus, Symb. Sin. 4: 20. 1929) = Campylopus
subporodictyon (Brotherus) B. H. Allen & Ireland, Lindbergia (In
press). |
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