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BFNA Title:
Bryum |
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XX. BRYUM Hedwig, Sp. Musc. Frond., 178.
1801 * [Greek bryum, a moss] John R. Spence Plants small, gregarious or in dense mats
or rarely cushions, white, silver-green, olive to pale green, golden,
yellow-green, brown or yellow-brown. Stems
0.2--1(--1.5) cm, weakly to strongly rounded julaceous or short-gemmiform,
not or weakly branched, innovations smaller than fertile stems, strongly
julaceous; stolons absent; rhizoids scarce or common, micronemata and
macronemata absent from stems or present in clusters proximally. Leaves dimorphic, fertile stem leaves
imbricate dry, erect to erect-spreading when wet, ovate-lanceolate to ovate,
flat or concave, 0.2--1(--1.5) mm, base straight or slightly curved at
insertion, not decurrent, innovation leaves similar but smaller than fertile
stem leaves; margins plane distally, recurved proximally or often plane
throughout, 1-stratose, more or less smooth, limbidium absent, apex obtuse to
acute or rarely acuminate, sometimes hyaline, costa not reaching apex or
excurrent in smooth often hyaline point, apiculus sometimes present if costa
not reaching apex, costa in transverse section with stereid band single,
usually well developed, guide cells typically absent; adaxial supracostal
cells irregularly to regularly quadrate or short-rectangular at base, laminal
cells distinctly heterogeneous, distal cells short-rhomboidal to
elongate-hexagonal or rarely vermicular, (2--)3--6(--8):1, not in rows
oblique to the costa, thin-walled to incrassate, proximal cells usually
quadrate or short-rectangular, 1--2(--3):1, wider than more distal cells,
medial cells generally similar to distal cells, walls not pitted, alar cells
not or somewhat differentiated from juxtacostal cells, usually shorter. Specialized asexual reproduction by
small leafy bulbils in axils of leaves, rarely of rhizoidal tubers. Sexual condition dioicous, perigonia
and perichaetia terminal, leaves the same size as vegetative leaves or
typically larger, not forming a rosette, inner leaves not much
differentiated. Seta 1, straight
to somewhat twisted. Capsule
inclined to erect, small, (1--)2--3 mm, elongate-pyriform or ovate,
hypophysis differentiated or not, sometimes thickened and rugose, exothecial
cells near mouth quadrate or short-rectangular, thick walled, reddish, in
1--2 rows, more proximal cells longer, irregularly long-rectangular with straight or sinuose
walls; annulus usually present, revoluble; operculum weakly convex,
short-conic, not rostrate; peristome double, exostome pale yellow or tan,
teeth slender lanceolate, trabeculate, lacking pores along fissural line,
endostome hyaline to pale yellow, separate from exostome, or sometimes adherent
or absent, segments present, basal membrane low to high, cilia present,
appendiculate, or sometimes absent; calpytra fugacious, cucullate, small,
smooth. Spores shed singly, not as
tetrads, not germinating in capsule, 8--15(--18) \um, finely papillose, pale
tan or yellow-tan. Species
40 (7 in the flora): temperate to Arctic-alpine regions worldwide, and in
mountains of subtropical or tropical regions. Bryum in the strict sense is a genus of tiny julaceous plants,
morphologically similar to Anomobryum. Molecular studies, however,
consistently show that the types of the two genera, A. julaceum and B.
argenteum, are not closely related. Species of Anomobryum can
generally be distinguished from Bryum by their vermicular distal
laminal cells, and elongate very slender, string-like stems. Bryum
species tend to have shorter laminal cells and thicker more rounded stems
that are relatively short. Additional
studies are needed with a larger sample of species to confirm the molecular
results. Bryum consists of both silver-white species lacking
chlorophyll in the distal portions of the leaves, and green to yellow-green
species. Many collections are
difficult to identify as they often consist of very small sterile shoots. There
are at least three undescribed species in the flora area, two of which are
discussed under related species. The third is highly distinctive and is from
southeastern SELECTED
REFERENCES Ochi, H. 1980. A revision
of the Neotropical Bryoideae, Part 1. J. Faculty Educ. Tottori Univ., Nat.
Sci. 29: 49--154. Shaw, A. J. 1981.
The taxonomy of Bryum oblongum and B. blindii. Canad. J. Bot.
59: 1426--1435. Frahm, J.-P. 2002. The
taxonomic status of Bryum arachnoideum C. Müll. and B. lanatum
(P. Beauv.) Brid. Trop. Bryol. 21: 53--56. Pedersen, N., C. J. Cox and L.
Hedenäs. 2003. Phylogeny of the moss family Bryaceae inferred from
chloroplast DNA sequences and morphology. Syst. Bot. 28: 471--482. Spence, J.
R. 1986. Bryum calobryoides, a new species from western 1. Plants silver-green or white, distal lamina hyaline, including apiculus or awn, distal laminal cells hexagonal to rhomboidal, less than 15 \um wide. 2.
Plants hoary white, stems evenly foliate, slender, costa strong, excurrent in
stout awn, somewhat recurved when dry; leaf axis bulbils lacking …….…………...…
5. Bryum lanatum 2.
Plants silver to silver-green, stems julaceous to gemmiform, costa not
reaching apex, apiculus usually present or sometimes absent, irregularly
incurved when dry; leaf axis bulbils present
......................................................................................................................
1. Bryum argenteum 1. Plants yellow-green, golden, olive-green or bright green, distal lamina not hyaline although apiculus if present sometimes hyaline, distal lamina cells variable, elongate vermicular to short and rhomboidal, 6--25 \um wide. 3.
Distal laminal cells of innovation leaves elongate-vermicular, more than 6:1,
and narrow, less than 8 \um; bulbils sometimes present in leaf axils; leaf
base typically red ........…………..…................... 2. Bryum blindii 3. Distal laminal cells of innovation leaves not vermicular, shorter and broader, 2--4:1, mostly more than 8 \um wide; bulbils absent; leaf base red or green. 4.
Plants golden or yellow-green; leaves triangular-ovate, costa strong,
excurrent in long awn, erect-spreading when dry
..............................................................................
4. Bryum chryseum 4. Plants yellow-green, olive-green or bright green; leaves ovate to ovate-lanceolate, costa not reaching apex or rarely excurrent in a short stout awn. 5.
Plants yellow-green, laminal cells of fertile stem leaves elongate-hexagonal,
4--5(--6):1; leaf base red .................…………… 6. Bryum oblongum 5. Plants olive green to bright green, laminal cells of stem leaves shorter, 2--3(--4):1, irregularly rhomoboidal to hexagonal; leaf base green. 6.
Leaf apex acute, not cucullate, apiculus lacking or composed of 1--2 cells,
distal laminal cells regularly hexagonal, 3--4:1, 10--16 \um wide, basal
cells predominantly rectangular in alar region, 2--3:1
................................ 7. Bryum
veronense 6.
Leaf apex rounded-obtuse to acute, cucullate, apiculus often present,
generally of more than 2 cells, distal laminal cells short and irregularly
rhomboidal, mostly 2--3:1, 12--25 \um wide, basal cells predominantly
quadrate in alar region ....... 3. Bryum
calobryoides 1. Bryum argenteum Hedwig, Spec. Musc. Frond., 181. 1801 Plants gregarious or in dense mats,
white-green to silver-green. Stems
0.2--1 cm, strongly rounded julaceous or sometimes gemmiform Leaves imbricate dry, erect when wet,
ovate to ovate-lanceolate, somewhat concave, 0.3--1(--1.2) mm; margins plane
distally or rarely recurved proximally, apex broadly rounded to acute, hyaline in distal 1/4--1/2 of leaf or
rarely nearly entirely green, costa not reaching apex, hyaline apiculus
usually present, sometimes short or nearly absent; distal laminal cells
elongate-hexagonal, (30--)40--80 x 10--15, 3--5:1, thin walled or somewhat
thickened but not distinctly incrassate, proximal cells usually quadrate or
short-rectangular, 1--2:1, 12--18 \um wide. Specialized asexual reproduction by small leafy bulbils in axils
of leaves. Seta elongate, brown
to red-brown, 1--2 cm, somewhat twisted when dry. Capsule inclined to pendant, 2--3 mm, ovate, red to red-brown,
hypophysis differentiated, somewhat thickened. Spores 8--15 \um. 1. Stems
loosely julaceous, leaves somewhat distant, green except for tips, apiculus
long ....................................................... 1b. Bryum
argenteum var. majus 1. Stems
densely julaceous or sometimes short and gemmiform, leaves silver-green,
hyaline in proximal 1/4--1/2 of leaf, apiculus short or long. 2.
Plants small, stems mostly less than 2 mm, sometimes gemmiform, leaves often
wider than broad, distal lamina cells relatively short, (2--)3--4:1, apiculus
very short or sometimes absent
................................................................................................1c.
B. argenteum var. muticum 2.
Plants larger, stems 2--10 mm, julaceous, leaves usually longer than broad,
distal lamina cells elongate, (3--)4--6:1, apiculus present, generally well
developed
...............................................................................................1a.
B. argenteum var. argenteum Bryum argenteum is perhaps the most widespread and
distinctive moss in the world, although in many regions it is found primarily
in urban or other heavily disturbed sites, and is mostly absent from native
undisturbed habitats in the tropics.
There are about 15 silver-white species described, with species
definitions based on a combination of one of
three or four different basic gametophyte morphologies combined with
subtle differences in the sporophytes.
However, much of the gametophyte variability in the complex is also
exhibited by B. argenteum itself, thus confusing species-level
identifications. This complex is urgently in need of world-wide molecular and
morphological studies. 1a. Bryum
argenteum Hedwig
var. argenteum Plants silvery-green. Stems distinctly
rounded julaceous, 0.5--1.0 cm. Leaves strongly imbricate, ovate to
ovate-lanceolate, longer than broad, hyaline in distal 1/3--1/4 of leaf,
apiculus well developed; distal laminal cells elongate-hexagonal,
3--4(--5):1. Capsules mature spring--summer (Apr--Jul). Common on soil or soil over rock or in crevices, often in nitrogen enriched sites, usually in disturbed habitats; 0--4000 m; Greenland; St. Pierre and Miquelon; 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., Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Mexico; West Indies; Central America; South America; Eurasia; Africa; Atlantic Islands (Bermuda); Indian Ocean Islands; Pacific Islands (New Zealand); Australia; Antarctica. 1b. Bryum
argenteum var. majus Schwägrichen, Sp. Musc. Frond., Suppl. 1, 2: 88. 1816 Plants greenish. Stems julaceous,
0.5--1 cm. Leaves loosely imbricate, ovate to ovate-lanceolate, longer
than broad, hyaline near the leaf tip, apiculus well developed, long; distal
laminal cells elongate-hexagonal, 3--4:1. Capsules
unknown. Rare, shaded moist soil, disturbed habitats; 0--500 m; N.H., Mo; w Bryum argenteum var. majus is poorly understood, but seems distinctive. It may be more
widely distributed. The pale green loosely
imbricate stems with hyaline apiculus are reminiscent of Plagiobrym zierii,
bit that species has wide elongate laminal cells throughout the leaf, a
pinkish coloration, and Arctic-alpine distribution. 1c. Bryum
argenteum var. muticum Bridel, Bryol. Univ. 1: 846. 1827 Plants hoary white to silver-green. Stems
gemmiform to shortly julaceous, 0.2--0.8 cm. Leaves ovate to
ovate-lanceolate, often broader than long, hyaline in distal 1/2--1/4 of
leaf, apiculus absent or very short, composed of 1--2 cells; distal laminal
cells short-hexagonal, (1--)2--3:1, sometimes a few quadrate cells present. Capsules
unknown. Common, dry soil, soil over rock, crevices, lowland deserts to dry
alpine tundra; 0--4,000 m; Ariz., Calif., Colo., Nev., N.Mex., Utah. The var. muticum is widespread in extreme
environments, but the world distribution is not well known. Similar material from Antarctica and 2. Bryum blindii
Bruch, Schimper & W. Gümbel, Bryol. Eur. 4: 163. 1846 Plants gregarious, green to
yellow-green. Stems 0.2--1 cm,
gemmiform to strongly rounded-julaceous. Leaves
imbricate dry, erect when wet, ovate, somewhat concave, 0.3--1(--1.2) mm;
margins plane, apex broadly acute, not hyaline in distal portion of leaf,
costa not reaching apex, apiculus
absent; distal laminal cells of main (fertile) stem and innovation leaves
linear-vermicular to elongate-hexagonal, (60--)70--90(--100) x 6--10(--12),
(6--)8--10:1, with yellowish thick walls, proximal cells usually quadrate or
short-rectangular, 1--2:1, 8--12 \um wide. Specialized asexual reproduction by small leafy bulbils in axils
of leaves. Seta elongate, red
to red-brown, 1--2 cm, somewhat twisted when dry. Capsule inclined to pendant, 1--2 mm, ovate, red to red-brown,
hypophysis differentiated, somewhat thickened and rugose when dry. Spores
10--18 \um. Capsules
mature summer (June--Aug). Rare, calcareous mineral soil, soil banks,
cold-temperate to arctic-alpine regions; 0--3500 m; Greenland; B.C., N.W.T.,
Nunavut, Ont., Yukon; Cal., Colo., Vt., Maine, Mont.; n Eurasia. One of the two
collections of Bryum blindii known from Colorado has leaves with a
strongly excurrent costa and relatively short distal laminal cells (3--5:1),
and is not typical material of the species. 3. Bryum calobryoides J. R. Spence, Bryologist 89: 215--218, fig. 1--8. 1986 Plants gregarious or in dense mats or
cushions, bright green distally, brown proximally. Stems 0.5--1.5(--2) cm, strongly rounded julaceous. Leaves imbricate dry, erect when wet,
ovate to suborbicular, concave, 0.2--1(--1.2) mm; margins plane distally,
weakly recurved proximally, apex broadly rounded to acute, not hyaline, costa not reaching apex,
apiculus typically absent in distal leaves, present in proximal leaves,
sometimes hyaline; distal laminal cells irregularly rhomboidal, (25--)30--75
x (8--)12--25, 1--4:1, thin walled or somewhat thickened but not distinctly
incrassate, proximal cells usually quadrate or short-rectangular, 1--2:1,
12--18 \um wide. Specialized asexual
reproduction lacking. Sporophytes
unknown. Uncommon to
locally common, primarily on calcareous damp soil, rocks; 1000--3000 m;
Alta., B.C.; Bryum calobryoides is easily distinguished by small
strongly julaceous stems, strongly concave leaves, and distal leaves broadly
rounded and cucullate. An undescribed species from 4. Bryum
chryseum Mitten, J.
Linn. Soc., Bot. 12: 304. 1869 Plants gregarious or in dense mats,
shiny golden-yellow to yellow-green or rarely pale green. Stems 0.5--1 cm, slender, weakly
julaceous, clusters of red rhizoids often present on stem. Leaves imbricate dry, erect when wet,
triangular to ovate, concave, 0.5--1 mm; margins plane distally or rarely
recurved proximally, apex acuminate to acute,
not hyaline, costa strong, long-excurrent in slender colored awn,
recurved when dry; distal laminal cells elongate-hexagonal to vermicular,
(50--)60--90 x 8--12, (4--)6--8:1, thin to somewhat firm walled but not
strongly incrassate, proximal cells usually quadrate or short-rectangular,
1--2:1, 12--18 \um wide. Specialized
asexual reproduction lacking. Seta
elongate, red, 1--2 cm, somewhat twisted when dry. Capsule inclined to pendant, 3--4 mm, clavate to pyriform, brown,
hypophysis slender, not differentiated; exostome sometimes reduced, with
cilia sometimes short or nearly absent. Spores (8--)10--15 \um (in
Mexican material). Capsules
unknown in the flora area. Rare, soil, Mediterranean and other seasonally dry
climates; 200--800 m; Bryum chryseum was found in 5. Bryum
lanatum (P. Beauvois)
Bridel, Muscol. Recent. Suppl. 3: 20. 1817 Bryum
argenteum var. lanatum
(P. Beauvois) Hampe, Linnaea 13: 44. 1839 Plants gregarious or in dense mats,
hoary white. Stems 0.5--1(--1.5)
cm, weakly julaceous. Leaves
imbricate dry, erect-spreading when wet, ovate to ovate-lanceolate, somewhat
concave, 0.3--1(--1.5) mm; margins plane distally or recurved proximally,
apex acute, hyaline in distal 1/2 of
leaf, costa excurrent in long slender hyaline awn, recurved when dry; distal
laminal cells elongate-hexagonal, 40--60 x 10--16, 4--5:1, walls somewhat
thickened to distinctly incrassate, proximal cells usually quadrate or
short-rectangular, 1--2:1, 10--16 \um wide. Specialized asexual reproduction absent. Seta elongate, brown to red-brown, 1--2
cm, somewhat twisted when dry. Capsule
inclined to pendant, (1--)2--3 mm, ovate, brown to red-brown, hypophysis
differentiated, somewhat thickened and rugose. Spores 8--15 \um. Capsules rare, mature spring--summer (May--Jul). Common to abundant on
soil, soil over rock or rock in drier climates; 0--4200 m.; Greenland; Alta., B.C., Man., Nfld. and Labr.,
N.W.T., N.S., Nunavut, Que., Sask., Yukon; Alaska, Ariz., Calif., Colo.,
Idaho, Kans., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Okla., Oreg., S.Dak., Tex., Utah,
Wash., Wyo; Mexico; West Indies; Central America; South America; Eurasia;
Africa; Atlantic Islands (Bermuda); Pacific Islands (Hawaii, New Zealand); Australia; Antarctica. Although
typically considered a variety of Bryum argenteum, B. lanatum from western 6. Bryum
oblongum Lindberg,
Bot. Not. 1882: 26. 1882 Plants gregarious, green to
yellow-green. Stems 0.2--1 cm,
gemmiform to strongly rounded-julaceous. Leaves
imbricate dry, erect when wet, ovate, somewhat concave, 0.3--1(--1.2) mm;
margins plane, apex broadly acute, not hyaline in distal portion of leaf,
costa not reaching apex, apiculus
absent; distal laminal cells of main (fertile) stem leaves
elongate-hexagonal, (30--)35--60(--70) x 6--12 , 4--5(--6):1, thin-walled,
not yellowish, distal laminal cells of innovation leaves shorter, proximal
cells usually quadrate or short-rectangular, 1--2:1, 8--12 \um wide. Specialized asexual reproduction by
small leafy bulbils in axils of leaves.
Seta elongate, red to red-brown, 1--2 cm, somewhat twisted when
dry. Capsule inclined to pendant,
1--2 mm, ovate, red to red-brown, hypophysis slender to weakly
differentiated, sometimes slightly thickened and weakly rugose when dry. Spores
10--18 \um. Capsules
mature summer (June--Aug). Rare, neutral mineral soil or soil banks, boreal
to Arctic-alpine regions; 0--1500 m; Greenland; B.C., Yukon; Alaska; n
Eurasia. Shorter
laminal cells of the innovations leaves distinguish B. oblongum from
the closely related B. blindii. A. J. Shaw (1981) also enumerated other
differences, including generally shorter exostome teeth in B. oblongum
(300--400 \um) against. longer teeth in B. blindii (400--500 \um).
Sterile material from 7. Bryum
veronense De Notaris,
Comment. Soc. Crittog. Ital. 2: 212 [112]. 1866 Plants in dense mats, dark green to
olive-green. Stems 0.4--1 cm, weakly
julaceous to string-like. Leaves
imbricate when dry, erect when wet, ovate, weakly concave, not cucullate,
0.2--1 mm; margins plane distally or rarely recurved proximally, apex acute,
not hyaline, costa not reaching apex, apiculus lacking or a very short
apiculus of 1--2 hyaline cells sometimes present; distal laminal cells
hexagonal, (25--)30--55 x 10--16, mostly 3:1, thin walled to somewhat
thickened but not distinctly incrassate, proximal cells usually
short-rectangular, at least in alar region, 2--3:1, 12--18 \um wide. Specialized asexual reproduction
lacking. Sporophyte unknown. Capsules
unknown. Very rare, damp to dry soil, soil-filled crevices in sandstone; 1700
m.; Greenland; Colo.; Europe. Bryum veronense has been recently collected
from the Front Range of Colorado near
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