View source for Dichelyma

{{Treatment/ID
|accepted_name=Dichelyma
|accepted_authority=Myrin
|publications={{Treatment/Publication
|title=Kongl. Vetensk. Acad. Handl.
|place=1832: 273, plates 6, 7. 1833
|year=1833
}}
|basionyms=
|synonyms=
|hierarchy=Fontinalaceae;Dichelyma
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Fontinalaceae]]</div><div class="higher-taxon"><small>genus</small>[[Dichelyma]]</div></div>
|etymology=Greek dicha, in two, and elyma, veil, alluding to large dimidate or cucullate calyptra
|volume=Volume 28
|mention_page=page 13, 490, 492, 655
|treatment_page=page 491
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>small to large, glossy. <b>Stems</b> prostrate or pendent; rhizoids from initials abaxial to leaf insertions, not or irregularly branched; axillary hairs 100–300 µm. <b>Leaves</b> distant or crowded, lanceolate to linear-lanceolate, keeled, conduplicate; margins plane or very narrowly recurved, entire or obscurely serrulate proximally, serrulate distally; apex obtuse, acute, or filiform-acuminate; costa subpercurrent to long-excurrent; alar cells quadrate or rectangular, not or slightly enlarged, walls firm; medial laminal cells linear to linear-rhomboidal. <b>Perigonia</b> lateral in leaf axils. <b>Perichaetia</b> with leaves elongate, sheathing setae. <b>Seta</b> 3–15(–20) mm. <b>Capsule</b> immersed, laterally emergent, emergent, or exserted, oval, oval-oblong, subcylindric, or cylindric; annulus rudimentary; operculum conic or obliquely long-rostrate; endostome trellis imperfect or perfect. <b>Calyptra</b> long-cucullate, covering capsule and often clasping base of seta when young. <b>Spores</b> 10–17 µm.</span><!--

-->{{Treatment/Body
|distribution=North America;Europe;Asia.
|discussion=<p>Species 5 (4 in the flora).</p><!--
--><p><i>Dichelyma</i> is often considered an aquatic moss, but is semi-aquatic. Distinctive gametophytic features include long, narrow, keeled-conduplicate leaves with strong, single costae and weakly developed, not or scarcely bulging alar cells. The keeled-conduplicate leaves lie flat on one side when placed on a microscope slide and so when measuring leaf width it is necessary to double the measurement. <i>Dichelyma</i> has long setae and long (to 7 mm), sheathing perichaetial leaves. The stems lack paraphyllia and pseudoparaphyllia, and the axillary hairs have brownish basal cells and hyaline distal cells. The endostome segments are longer than the exostome teeth. <i>Dichelyma</i> is often confused with species of <i>Drepanocladus</i> (in the broad sense). However, many species of <i>Drepanocladus</i> have inflated alar cells, and these all differ from <i>Dichelyma</i> in having plane to concave leaves that are often spirally twisted when dry and not three-ranked. <i>Blindia</i> (Seligeriaceae) has also been confused with <i>Dichelyma</i>; <i>Blindia</i> is acrocarpous, much smaller, and has well-developed, inflated alar cells, concave leaves, elongated setae, and a single, haplolepidous peristome. The fifth species in the genus, <i>Dichelyma</i> japonicum Cardot, is endemic to Japan.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Leaves strongly falcate to circinate at stem and branch apices.
|[[Dichelyma uncinatum|Dichelyma uncinatum]]
|-id=key-0-1
|1
|Leaves erect-ascending to weakly falcate at stem and branch apices
|[[#key-0-2| > 2]]
|-id=key-0-2
|2
|Medial stem leaves 0.7-1.4 mm wide; capsules exserted; endostome trellis perfect.
|[[Dichelyma falcatum|Dichelyma falcatum]]
|-id=key-0-2
|2
|Medial stem leaves 0.4-0.8 mm wide; capsules immersed or laterally emergent; endostome trellis imperfect
|[[#key-0-3| > 3]]
|-id=key-0-3
|3
|Leaves linear-lanceolate; apices filiform-acuminate; costae long-excurrent.
|[[Dichelyma capillaceum|Dichelyma capillaceum]]
|-id=key-0-3
|3
|Leaves lanceolate; apices subulate to acuminate, acute to obtuse; costae sub- percurrent to percurrent.
|[[Dichelyma pallescens|Dichelyma pallescens]]
|}
</div></div><!--

-->{{#Taxon:
name=Dichelyma
|authority=Myrin
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Fontinalaceae
|distribution=North America;Europe;Asia.
|reference=None
|publication title=Kongl. Vetensk. Acad. Handl.
|publication year=1833
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-data-curation.git/src/bb6b7e3a7de7d3b7888a1ad48c7fd8f5c722d8d6/coarse_grained_fna_xml/V28/V28_764.xml
|genus=Dichelyma
}}<!--

-->[[Category:Treatment]][[Category:Fontinalaceae]]