Drepanocladus

• Authority

  Hedenäs, Lars. 2003. Amblystegiaceae. Fl. Neotrop. Monogr. 89: 1--107. (Published by NYBG Press)

• Family

  Campyliaceae

• Scientific Name

  Drepanocladus

• Type

  Type. Hypnum aduncum Hedw. (Drepanocladus aduncus (Hedw.) Wamst.) (typ. cons., Isoviita & Ochyra, 1990; Greuter et al., 1994). The genus name is derived from the Greek drepane, sickle, and clados, branch.

• Synonyms

  Calliergidium, Richardsiopsis, Hypnum aduncum Hedw., Drepanocladus aduncus (Hedw.) Warnst., Richardsiopsis lacustris (Herzog & P.W.Richards) Ochyra

• Description

  
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  Genus Description - Plants medium-sized or large; green, yellow green, yellowish, or brownish. Stem sparsely and irregularly to ± pinnately (distichously) branched; central strand present; hyalodermis absent; pseudoparaphyllia foliose; paraphyllia absent; rhizoids smooth, slightly or occasionally strongly branched, inserted on stem at or just below leaf insertions; axillary hairs with 1-2(-3) upper hyaline cells. Stem leaves straight or falcate (gradually curved) from erect to spreading base, or ± erect to spreading from more erect base, the base ovate to broadly ovate, or triangular-ovate or rounded-triangular or cordate, narrowing gradually or abruptly to apex, not plicate, concave, not or hardly decurrent; acumen sometimes squarrose (outside the area particularly squarrose or sometimes distinctly set off from rest of leaf), sometimes distinctly furrowed, the apex long-acuminate to obtuse; margin plane, entire or slightly denticulate; costa mostly single or sometimes branched and extending 40% of way up leaf to excurrent (or, especially outside the area, double and extending 25-50% of way up leaf); median laminal cells linear, unistratose or rarely partially bistratose, slightly incrassate or incrassate, eporose or slightly porose, smooth; lower alar cells inflated, short-linear to short-rectangular, hyaline and thin-walled or slightly incrassate, toward costa less inflated and sometimes more strongly incrassate and porose; upper alar cells quadrate or short-rectangular, slightly widened, thin-walled and eporose; alar group distinct, transverse-triangular or quadrate (outside area rarely decurrent). Branch leaves smaller and narrower than stem leaves; proximal branch leaves triangular or short- to long-ovate, obtuse to acuminate. Autoicous, synoicous or dioicous. Perigonia in autoicous species usually below perichaetia; perigonial leaves narrowing gradually or abruptly from broad basal portion to acuminate or long-acuminate apex. Inner perichaetial leaves narrowing gradually or abruptly to acuminate apex, plicate or slightly plicate; margin bordered or not at shoulder, entire or finely denticulate in acumen and at shoulder; costa single or double, ending 30-90% of way up leaf or excurrent; laminal cells smooth; vaginula with para-physes. Calyptra naked. Seta long, red; capsule cylindrical or short-cylindrical, curved or slightly curved, horizontal; annulus separating; operculum conical. Exostome well developed; teeth cross-striolate on outer surface below, papillose above, sometimes with papillae in longitudinal rows; margin entire or slightly dentate. Endostome well developed, with high basal membrane; segments not or narrow-perforate; cilia 2-4, well developed, nodose or partially short-appendiculate. Spores 11.0-31.5 µm, papillose. [Sporophytes not known from neotropical material.]

• Discussion

  Note. In the genus Drepanocladus, the ratio of median laminal cell length (µm)/leaf length (mm) has turned out to be useful in separating several taxa. To evaluate this character, study 8-10 adjacent stem leaves and use the median value of the size ranges when calculating the ratio.

• Distribution

  Drepanocladus includes nine species, and the genus is widespread in the temperate zones of both hemispheres. Some species occur also in tropical and subtropical areas, mainly at higher altitudes. Five species occur in tropical S America.