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BFNA Title: Drepanocladus |
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level R ver. 3 AMBLYSTEGIACEAE--
Drepanocladus Lars Hedenäs Hypnum subsect. Drepanocladus Müller
Hal., Syn. Musc. Frond. 2: 321. 1851; Calliergidium (Renauld) Grout. Plants medium-sized or rather large, green, yellow-green,
yellowish or brownish. Stem
sparsely and irregularly to more or less pinnately branched ± in one plane,
with central strand and without a hyalodermis; paraphyllia absent; rhizoids or
rhizoid initials only on stem or at abaxial leaf costa insertion, smooth,
slightly or occasionally strongly branched; axillary hairs with 1--3 distal
hyaline cells. Stem leaves
erect-spreading to spreading, straight or falcate, or from erect, sub-clasping
base ± erect to spreading, sometimes squarrose, ovate, rounded-triangular, or
cordate, gradually or suddenly narrowed to longly acuminate to obtuse apex,
not plicate, concave, above sometimes channeled; marginal lamina cells
1-stratose, margin plane, entire or slightly denticulate; costa double and
short or single and long, sometimes excurrent; median lamina cells linear,
smooth; differentiated alar cells numerous, distal cells quadrate or shortly
rectangular, slightly widened, proximal cells shortly rectangular to shortly
linear, inflated and hyaline, widest cells 17--31.5 \um wide, forming a
distinct transversely triangular or ± quadrate group, reaching from leaf
margin (25--)40--100% of distance to leaf middle at insertion, not decurrent
except in D. cardotii. Sexual condition autoicous, synoicous
or dioicous. Inner perichaetial leaves
gradually or suddenly to narrowed acuminate apex, plicate or slightly so;
margin entire or finely denticulate distally; lamina cells smooth. Capsule cylindric, curved and
horizontal; peristome perfect; exostome margin entire or slightly dentate
above. Spores 11--31.5 \um. Species 10 (7
in the flora): nearly worldwide. Species of the
genus Drepanocladus are found in ± mineral- and ± nutrient-rich
habitats. They may be relatively large (stem leaves up to SELECTED
REFERENCES Hedenäs, L.1996. On the interdependence of some leaf characters
within the Drepanocladus aduncus-polycarpus complex. J. Bryol. 19:
311--324. Hedenäs, L. Note: In the
following key, as well as in the species descriptions, the ratios between the
lamina cell and leaf sizes should be based on measurements in 8--10 adjacent
stem leaves. The total size ranges should be searched for, and the median
values of these should be used for the calculations of the ratios. 1. Autoicous
(in D. cardotii sexual condition
unknown); leaves from ± straight and erect bases usually with leaf acumina ±
spreading, or squarrose; leaf acumen furrowed. 2.
Small species, stem leaves 1--1.4 mm; narrowly decurrent 25--75% of distance
to leaf below; very rare species . . .
4. Drepanocladus cardotii 2.
Medium-sized to large species, stem leaves normally 1.7-- 3.
Stem leaf insertion shallowly curved to almost straight; leaf base when moist
concave, erect to ± spreading, acumen gradually differentiated from basal
leaf but frequently more spreading than leaf base, straight or falcate,
furrowed; costa double and extending 30--50% way up leaf or single and
extending 40--65% way up, leaves 0.6--1(--1.1) mm wide; temperate and Arctic
species . . . 2. Drepanocladus
polygamus 3.
Stem leaf insertion usually deeply U-shaped; leaf base when moist concave or
strongly concave, erect and sub-clasping, acumen usually sharply
differentiated from basal leaf and (erect), patent, spreading or squarrose,
furrowed or strongly so; costa double and extending less than 25% way up
leaf, or if single extending less than 45% way up; leaves 0.6-- 1. Dioicous.
Leaves falcate-secund to sometimes entirely ± straight and erect; leaf acumen
in straight-leafed plants plane or at most slightly furrowed. 4.
Stem leaf costa excurrent or longly so, rarely ending a few cells before leaf
apex; one or both leaf margins often partly finely denticulate . . . 5. Drepanocladus longifolius 4.
Stem leaf costa ending well before leaf apex; leaf margin entire, or
occasionally very finely denticulate. 5.
Ratio of median leaf lamina cell length (/um) to leaf length (mm) between
37.6--45.6; stem leaves 1.1--2.1 x 0.5--0.7 mm; alar groups quadrate, shortly
transversely rectangular, or shortly transversely triangular, not reaching
costa; a rare Arctic species . . . 7. Drepanocladus
latinervis 5.
Ratio of median leaf lamina cell length (/um) to leaf length (mm) between
17.9--36.5 (in D. aduncus very
rarely to 38.2); stem leaves 0.9--5.2 x 0.4--1.6 mm; alar groups variously
developed; widespread species, sometimes occurring in Arctic areas. 6.
Alar groups transversely triangular, reaching costa or almost so; stem leaves
variously straight or falcate-secund, the latter especially in small plants
growing under relatively dry conditions . . . 1. Drepanocladus aduncus 6.
Alar groups quadrate or shortly transversely triangular, not reaching costa;
stem leaves mostly falcate-secund or strongly so, rarely weakly so, the
latter especially in submerged plants . . . 6. Drepanocladus sordidus 1. Drepanocladus aduncus (Hedwig)
Warnstorf, Beih. Bot. Centralbl. 13: 400. 1903 Hypnum
aduncum Hedwig, Sp.
Musc., 295. 1801; Brachythecium edentatum R. S. Williams; Calliergidium
bakeri (Renauld) Grout; Drepanocladus aduncus var. kneiffii
(Bruch, Schimper & W. T. Gümbel) Mönkemeyer; D. aduncus var. polycarpus
(Voit) G. Roth; D. aduncus var. pseudofluitans (Sanio)
Głowacki; D. kneiffii (Bruch,Schimper & W. T. Gümbel) Warnstorf; D.
simplicissimus Warnstorf; D.
stagnatus Żarnowiec Plants slender to robust. Stem pinnately or irregularly pinnately branched. Stem leaves with slightly curved
insertion, straight or usually falcate, ovate-lanceolate, ovate, triangular-ovate,
rounded-triangular or broadly ovate, gradually narrowed to (obtuse), acute,
or shortly to long-acuminate apex, leaves 0.9--5.1 x 0.4--1.6 mm, concave,
acumen in straight-leafed plants plane or at most weakly furrowed; margin
entire or occasionally very finely denticulate; costa single, ending in mid
leaf or above, well before leaf apex; ratio of median leaf lamina cell length
(/um) to leaf length (mm) between 17.9--35.5 (very rarely up to 38.2); alar
groups transversely triangular, reaching costa or almost so, not or hardly
decurrent. Sexual condition dioicous. The species
most likely to be confused with Drepanocladus aduncus is D.
polygamus, and the differences between these two are discussed with the
latter. Drepanocladus aduncus is frequently also confused with Warnstorfia
species, but the latter frequently get red colors when growing in exposed
habitats whereas D. aduncus never becomes red. In Warnstorfia species
the shoots are radially branched (in sparsely branched specimens this may be
difficult to see; distichously branched in Drepanocladus), and the
margins are mostly distinctly denticulate in at least some parts of the
leaves (most distinct just above the alar groups or near the leaf apex or
both; entire or almost so in D. aduncus). When several leaves are
checked, rhizoid initials are almost invariably found near the apex of at
least some leaves of most Warnstorfia species (very rare only in W.
trichophylla), whereas leaf-borne initials are never found in Drepanocladus.
Finally the very different ontogeny of the alar cells in these two genera is
a safe separating character for the very few specimens that are impossible to
identify by means of the above characters (see L. Hedenäs 1987). More or less
mineral- and nutrient-rich wetlands, such as eutrophic fens, shores, ditches,
or occasionally submerged in pools and lakes, sometimes also in swampy
forests; low to high elevations; Greenland; Alta., B.C., Man., N.B., Nfld.,
N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Ariz., Ark., Calif.,
Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Kans., Maine, Mass., Mich.,
Minn., Miss., Mo., Mont., N.C., Nebr., Nev., N.H., N.J., N.Mex., N.Y.,
N.Dak., Ohio, Oreg., Pa., S.Dak., Utah, Vt., Va., Wash., Wis., W.Va., Wyo.;
Mexico; West Indies; Central America; South America: Eurasia: Africa:
Australia: Indian Ocean Islands (Kerguelen): Pacific Islands (New Zealand). Because Drepanocladus
aduncus is very variable in habit several taxa have been segregated from
this species at one time or another. However, the quantitative characters
that were employed for separating these taxa are size-dependent, and
molecular evidence suggests that the described expressions are
environmentally induced. The phenotypes most frequently recognized at the
species level were small plants with short leaf cells and weak costae called D.
polycarpus, large plants, with long cells and strong costae called D.
aquaticus or D. stagnatus,
and intermediate plants called D. aduncus. In addition,
specimens with acute or sometimes obtuse leaf apices were called D.
simplicissimus or Calliergidium bakeri, but specimens of the
latter kind have sometimes typical D. aduncus leaves in some parts of
the stems, and “D. simplicissimus leaves” in other parts. The studied
two isosyntypes of Hypnum kneiffii var. filiforme S. Berggren
consist of the species Drepanocladus sordidus, and D. aduncus and
Scorpidium cossonii, respectively. 2. Drepanocladus polygamus (Bruch,
Schimper & W. T. Gümbel) Hedenäs, Bryologist 100: 82. 1997 Amblystegium polygamum Bruch, Schimper
& W. T. Gümbel, Bryol. Eur. 6: 60, figure 572. 1853 (fasc. 55--56 Mon. 16. figure 10); Campyliadelphus polygamus (Bruch,
Schimper & W. T. Gümbel) Kanda; Campylium polygamum (Bruch,
Schimper & W. T. Gümbel) C. E. O. Jensen; C. polygamum var. fluitans
Grout; C. polygamum var. minus
(Schimper) G. Roth. Plants medium-sized to rather large. Stem irregularly and sparsely to more
or less pinnately branched. Stem
leaves with slightly curved insertion, erectopatent to spreading, basal leaf
portion sometimes slightly more erect than rest of leaf, straight or falcate,
ovate, broadly ovate or rounded-triangular, mostly distinctly narrowed at
insertion, gradually narrowed to acuminate apex, acumen not or hardly set off
from leaf base, leaves (1.3--)1.7--3.5 x 0.6--1(--1.1) mm, concave, acumen
furrowed; margin entire or slightly sinuose; costa single or branched and
ending in mid leaf to 2/3 way up leaf, or double and ending before mid leaf;
ratio of median leaf lamina cell length (/um) to leaf length (mm) between
25.3--33.3; alar groups transversely triangular, reaching from margin 2/3 to
entire distance to costa, not or hardly decurrent. Sexual condition autoicous. More or less
mineral- and nutrient-rich wetlands, such as eutrophic fens, shores, ditches,
or occasionally submerged in pools and lakes, sometimes also in swampy
forests; low to high elevations; Greenland, Alta., B.C., N.B., Nfld., N.W.T.,
N.S., Nunavut, Ont., Que., Sask., Yukon; Alaska, Calif., Colo., Fla., Idaho,
Iowa, Maine, Mass., Mich., Minn., Mo., N.H., N.J., N.Y., Ohio, Wash., Wis.,
Wyo; West Indies; Central America; South America; Eurasia (including Papua
New Guinea); Africa; Australia; Pacific Islands (New Zealand); Antarctica. Some specimens
of Drepanocladus polygamus are very similar to D. aduncus.
However, D. polygamus is autoicous, whereas D. aduncus is
dioicous, and in most cases at least parts of the shoots of D. polygamus are reminiscent of species of Campylium,
such as C. stellatum, with the leaves ± spreading and acumen furrowed.
In D. aduncus the leaf acumen is more or less flat in straight-leafed
specimens, which are the ones likely to be confused with D. polygamus,
and the leaves are not spreading in a Campylium-like fashion. The identity
of Campylium polygamum var. longinerve (F. Renauld & J.
Cardot) A. J. Grout (Hypnum polygamum var. longinerve F.
Renauld & J. Cardot) is unclear, because no type material was available
for study. 3. Drepanocladus arcticus (R.
S. Williams) Hedenäs, Bryologist 100: 82. 1997 Chrysohypnum
arcticum R. S.
Williams, Rep. Canad. Arct. Exp. 1913--18, 4(E): 10. fig. 13--18. 1921; Campylium arcticum
(R. S. Williams) Brotherus; C. stellatum var. arcticum (R.
S. Williams) L. I. Savicz Plants medium-sized to large. Stem irregularly and often sparsely
branched. Stem leaves with usually
deeply U-shaped insertion, from erect and sub-clasping base with erect,
patent or spreading acumen, ovate, broadly ovate or triangular-ovate, only
weakly or sometimes not at all narrowed at their insertions, suddenly or
gradually narrowed to an acumen that is (1--)1.2--2.3 times as long as basal
leaf, apex acuminate, leaves (1--)1.7--3.6 x 0.6--1.5 mm, concave or strongly
concave, acumen furrowed or strongly furrowed; margin entire, or near apex
sometimes slightly sinuose; costa double and short, very rarely single and
then ending well before mid leaf; ratio of median leaf lamina cell length
(/um) to leaf length (mm) between 26--30.2; alar groups large, transversely
triangular, reaching from margin 2/3 to entire distance to costa, not or
hardly decurrent. Sexual condition autoicous. Rarely found
very far from the sea in Arctic areas, in association with lagoons, salt
water pools, shore meadows, fens, or in association with bird cliffs, in mineral-
and more or less nutrient-rich habitats; low elevations; Greenland, N.W.T.,
Nunavut, Alaska; Eurasia. Drepanocladus
arcticus has
frequently been confused with D. polygamus and Campylium stellatum,
all occurring in Arctic areas. Amblystegium chrysophyllum var. zemliae
C. E. O. Jensen (Campylium zemliae (C. E. O. Jensen) C. E. O.
Jensen) may be an older name for Drepanocladus arcticus. However,
because no type material of this taxon seems to be extant, and the protologue
does not allow certain conclusions regarding its identity, this cannot be
decided. Two duplicate specimens from C. E. O. Jensen’s herbarium and
originally identified as Campylium zemliae (Umanak, July 1834, Vahl),
in H and S, respectively, belong to Drepanocladus polygamus. 4. Drepanocladus cardotii (Thériot)
Hedenäs, Bryologist 100: 82. 1997 Hypnum
cardotii Thériot, Bot.
Gaz. 30: 125, plate 11, fig. 4. 1900;
Campylium cardotii (Thériot) Brotherus; C. stellatum subsp. cardotii
(Thériot) Grout Plants small. Stems irregularly and in many shoots sparsely branched. Stem leaves with slightly curved
insertion, from erectopatent to spreading base falcate or in some shoots
subsquarrose, cordate or broadly ovate, suddenly narrowed to an often curved
acumen that is 0.6--1.0 times as long as basal leaf, apex acuminate, leaves
1--1.4 x 0.7--0.8 mm, concave, acumen furrowed; margin finely denticulate or
sometimes with larger parts entire; costa usually forked shortly above base,
occasionally with 3--4 branches, ending well before mid leaf; ratio of median
leaf lamina cell length (/um) to leaf length (mm) 23.6 (only one specimen
seen); alar groups transversely triangular, reaching from margin 2/3--4/5 of
distance to costa, narrowly decurrent 1/4--3/4 of distance to next lower
leaf. Sexual condition unknown. Habitat
unknown; 2000 m; Drepanocladus cardotii is recognized by its small size, its Campylium-like
appearance, and by the long-decurrent leaves. This species is only known from
the type collection, 5. Drepanocladus longifolius (Mitten)
Brotherus ex Amblystegium longifolium Mitten, J. Linn.
Soc. Bot. 12: 571. 1869; Drepanocladus aduncus var. capillifolius (Warnstorf)
Riehmer; D. capillifolius (Warnstorf) Warnstorf; D. crassicostatus Janssens Plants medium-sized to large. Stems pinnately or more irregularly
branched. Stem leaves with
slightly curved insertion, erectopatent to patent, falcate or rarely almost straight,
ovate to triangular or broadly rounded triangular, gradually narrowed to
long-acuminate apex, leaves 1.5--6.4 x 0.5--1.3 mm, concave, acumen in
straight-leafed plants ± plane; margin entire or frequently partly finely
denticulate; costa single and strong, excurrent or longly so, rarely ending a
few cells before leaf apex; ratio of median leaf lamina cell length (/um) to
leaf length (mm) between 16.5--23.9(--25.5); alar groups transversely
triangular or narrowly so, reaching from margin 2/3--4/5 of distance to
costa, not or hardly decurrent. Sexual
condition dioicous. More or less
mineral- and nutrient-rich habitats, submerged in lakes and pools, ox-bow
lakes, water-filled kettle holes, sometimes periodically dry pools, small and
usually slowly flowing brooks, sometimes associated with springs,
periodically wet depressions in meadows; low to high elevations; Alta., B.C.,
Man., N.B., N.W.T., Ont., Que., Sask., Yukon; Alaska, Calif., Colo., Mich.,
Mont., Oreg., S.Dak., Utah, Wash., Wis., Wyo.; South America; Eurasia; Indian
Islands (Kerguelen); Australia. Drepanocladus
longifolius differs
from all other North American Drepanocladus species in its excurrent
leaf costa. Because of this trait, it can hardly be confused with any other Drepanocladus
s.l. species in 6. Drepanocladus sordidus (Müller
Hal.) Hedenäs in W. R. Buck, Mem. New York Bot. Gard. 82: 217. 1998 Hypnum sordidum Müller Hal., Bot.
Zeit. 14: 457. 1856; Cratoneuron sordidum (Müller Hal.) Brotherus; Drepanocladus
exannulatus var. mexicanus Cardot; Drepanocladus tenuinervis T.
J. Koponen Plants medium-sized, sometimes large or small.
Stems pinnately or irregularly
pinnately branched. Stem leaves with
slightly curved insertion, strongly falcate-secund, rarely only weakly so,
ovate, broadly ovate or triangular-ovate, gradually narrowed to acuminate
apex, leaves 1.4--5.2 x 0.4--1.4 mm, more or less strongly concave; margin
entire or partly very weakly, obtusely denticulate; costa single, ending
above mid leaf, mostly in acumen but not excurrent; ratio of median leaf
lamina cell length (/um) to leaf length (mm) between 23.3--36.5; alar groups small,
quadrate or shortly transversely triangular, reaching from leaf margin
2/5-3/5 of distance to costa, not or hardly decurrent. Sexual condition dioicous. Intermediately
mineral-rich, meso- to eutrophic habitats, frequently growing submerged in
lakes, pools, and ox-bow lakes, but also terrestrial wetland habitats such as
fens; low to high elevations; Greenland; Alta., B.C., Nfld., N.W.T., N.S.,
Nunavut, Ont., Yukon; Alaska, Calif., Ind., Iowa, Mass., Mich., Minn., N.J.,
N.Y., Nev., Okla., R.I., Wash., Wis.; Mexico; Central America; South America;
Eurasia. Drepanocladus
sordidus and D.
latinervis are recognized by their almost always strongly falcate leaves,
their relatively small alar groups, and their relatively strong, but
non-excurrent costa. For the differences between the two, see the notes after
the latter. Because the species of the Drepanocladus sendtneri (Schimper ex H. Müller) Warnst. and D. aduncus complexes
have only recently been understood, the North American distribution of D.
sordidus is at present likely to be incompletely known. The Eurasian and
African D. sendtneri is a species of strongly calcareous areas, where
it usually grows in shallow fens or in periodically wet depressions. It is
most safely distinguished from D. sordidus by a different ratio of
median leaf lamina cell length (/um) to leaf length (mm), between 17.9-24.4
(between 23.3-- 7. Drepanocladus latinervis Warnstorf, Beih. Bot. Centralbibl. 13: 416. 1903 Plants small. Stems sparsely and irregularly pinnately branched. Stem leaves with slightly curved
insertion, falcate-secund, ovate or broadly ovate, gradually narrowed to
acuminate apex, leaves 1.1--2.1 x 0.5--0.7 mm, more or less strongly concave;
margin entire or very weakly and obtusely denticulate; costa single, ending
just below mid leaf to 4/5 way up leaf; ratio of median leaf lamina cell
length (/um) to leaf length (mm) between 37.6--45.6; alar groups small,
transversely triangular, shortly transversely rectangular, or quadrate,
reaching from leaf margin 1/3--2/3 of distance to costa, not or hardly
decurrent. Sexual condition dioicous.
Apparently
growing in calcareous wetlands in the Arctic, but the exact habitat
requirements of this species are unclear; Considering
its wide Arctic Asian distribution, Drepanocladus latinervis is most
likely more widespread in OTHER
REFERENCES Hedenäs, L.
1987. On the ontogeny of alar cells in Drepanocladus aduncus, D.
exannulatus and some other species. J. Bryol. 14: 753--759. |
