View source for Mnium

{{Treatment/ID
|accepted_name=Mnium
|accepted_authority=Hedwig
|publications={{Treatment/Publication
|title=Sp. Musc. Frond.,
|place=188, plate 45. 1801
|year=1801
}}
|basionyms=
|synonyms=
|hierarchy=Mniaceae;Mnium
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Mniaceae]]</div><div class="higher-taxon"><small>genus</small>[[Mnium]]</div></div>
|etymology=Greek mnion, moss
|volume=Volume 28
|mention_page=page 10, 186, 216, 222, 224, 225, 243, 658, 659
|treatment_page=page 223
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>(0.5–)2–4(–8) cm, in open to compact tufts or mats. <b>Stems</b> red, reddish brown, or brown, rarely yellowish brown, erect, simple or branched distally, not dendroid; rhizoids brown, macronemata mainly proximal, micronemata absent. <b>Leaves</b> green to dark green, sometimes yellowish, often crisped and contorted, sometimes undulate, sometimes spirally twisted when dry, patent, erect-spreading, or spreading, usually ± flat when moist, elliptic, obovate, oblong-ovate, ovate, ovate-elliptic, ovate- or elliptic-lanceolate, or obovate-spatulate, 1.5–6.5 mm, proximal leaves much smaller; base short- to long-decurrent; margins plane, green, reddish brown, or brown, 1- or 2-stratose, sometimes multistratose with stereid band, toothed distally or to below mid leaf, teeth usually paired and often sharp, sometimes single, small, and blunt, rarely rounded or indistinct; apex acute, obtuse, rarely rounded, or acuminate, apiculate or sometimes cuspidate, cusp often toothed; costa percurrent or excurrent, rarely subpercurrent or ending well before apex, distal abaxial surface smooth or toothed; medial laminal cells usually elongate or ± isodiametric, sometimes oblong, (10–)17–50 µm, sometimes in diagonal or longitudinal rows, collenchymatous or not, walls usually not pitted (pitted in <i>M. arizonicum</i>); marginal cells differentiated, linear, short-linear, or rhomboidal, in 1–4(–5) rows. <b>Specialized</b> asexual reproduction absent. <b>Sexual</b> condition synoicous or dioicous. <b>Seta</b> single, rarely double or triple, usually yellowish and becoming red from base with age, 1–5 cm, straight or flexuose. <b>Capsule</b> horizontal to pendent, yellow, yellow brown, or brown, oblong-cylindric, 2–7 mm; operculum conic-mammillate or conic-rostrate; exostome brown, greenish yellow, yellowish brown, reddish brown, or purplish; endostome yellowish or brown. <b>Spores</b> 15–40 µm.</span><!--

-->{{Treatment/Body
|distribution=North America;Mexico;Central America (Guatemala);South America;Eurasia;Africa;circumboreal.
|discussion=<p>Species 19 (9 in the flora).</p><!--
--><p>In most cases, <i>Mnium</i> is distinguished from other genera of Mniaceae by the presence of paired teeth along the leaf margins. However, <i>M. blyttii</i> and <i>M. stellare</i> usually have single, indistinct marginal teeth, and leaves may lack teeth altogether. <i>Trachycystis flagellaris</i> also has paired marginal teeth but is readily distinguished by mammillose laminal cells. Depauperate plants of <i>M. arizonicum</i> and <i>M. thomsonii</i>, but also, in a few cases, <i>M. marginatum</i>, have leaves with only a few single, small teeth. Although <i>Mnium</i> is characterized by a wide range in morphological variation related to environmental conditions, plant age, and sexuality (T. J. Koponen 1974), most vigorous collections with well-developed leaves should be readily identified.</p><!--
--><p>Blue postmortal color (mnioindigon) is often used to separate <i>Mnium blyttii</i> and <i>M. stellare</i> from other species of <i>Mnium</i>. Although often observed in younger collections when leaves are soaked only in water, it is most readily observed in older specimens if plants are dipped sequentially in alcohol (70–90%), 2% KOH, and water.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Marginal cells in 1-2(-3) rows; margins 1-stratose, rarely 2-stratose in short sections; margins entire or weakly toothed distally, teeth single or rarely paired, small, blunt; blue postmortal color often present in laminal cells
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Marginal cells usually in more than 2 rows; margins 1- to multistratose, toothed often to below mid leaf, teeth usually paired, usually large and sharp, rarely nearly absent; blue postmortal color absent from laminal cells
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Leaves usually more than 2.5 mm; marginal cells linear; plants usually more than 2 cm.
|[[Mnium blyttii|Mnium blyttii]]
|-id=key-0-2
|2
|Leaves usually less than 2.5 mm; marginal cells short-linear or rhomboidal; plants usually less than 2 cm.
|[[Mnium stellare|Mnium stellare]]
|-id=key-0-3
|3
|Laminal cell walls pitted; marginal cells short-linear or rhomboidal.
|[[Mnium arizonicum|Mnium arizonicum]]
|-id=key-0-3
|3
|Laminal cell walls not pitted; marginal cells linear
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Leaves to 6 mm; costa ending well before apex or occasionally percurrent, distal abaxial surface strongly toothed, adaxial surface occasionally toothed; e North America.
|[[Mnium hornum|Mnium hornum]]
|-id=key-0-4
|4
|Leaves usually to 4(-5) mm; costa percurrent or excurrent, abaxial surface toothed or smooth, adaxial surface smooth (rarely toothed in M. spinosum); mostly widespread
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Medial laminal cells (10-)14-22(-25) µm.
|[[Mnium thomsonii|Mnium thomsonii]]
|-id=key-0-5
|5
|Medial laminal cells mostly more than 25 µm
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Leaves usually obovate; marginal teeth long, sharp, usually restricted to distal 1/2 of leaf; margins multistratose with stereid band; laminal cells not collenchymatous.
|[[Mnium spinulosum|Mnium spinulosum]]
|-id=key-0-6
|6
|Leaves ovate-elliptic, elliptic, or oblong-ovate, rarely obovate; marginal teeth large or small, sharp or blunt, usually to below mid leaf; margins 2- or multistratose, stereid band usually absent (present in M. spinosum); laminal cells collenchymatous or not
|[[#key-0-7| > 7]]
|-id=key-0-7
|7
|Laminal cells not or weakly collenchymatous; marginal teeth large, sharp; arctic or alpine.
|[[Mnium spinosum|Mnium spinosum]]
|-id=key-0-7
|7
|Laminal cells usually strongly collenchymatous; marginal teeth small to large, sharp or blunt; widespread
|[[#key-0-8| > 8]]
|-id=key-0-8
|8
|Leaves narrowly elliptic, ovate-elliptic, or ovate-oblong; marginal teeth long, sharp, occasionally short and blunt; costae with distal abaxial surface toothed; sexual condition dioicous.
|[[Mnium lycopodioides|Mnium lycopodioides]]
|-id=key-0-8
|8
|Leaves usually ovate-elliptic; marginal teeth small to large, blunt or occasionally sharp; costae usually smooth, on well-developed leaves distal abaxial surface rarely with few blunt teeth; sexual condition synoicous or rarely dioicous.
|[[Mnium marginatum|Mnium marginatum]]
|}
</div></div><!--

-->{{#Taxon:
name=Mnium
|author=Terry T. McIntosh;Steven G. Newmaster
|authority=Hedwig
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Mniaceae
|distribution=North America;Mexico;Central America (Guatemala);South America;Eurasia;Africa;circumboreal.
|reference=None
|publication title=Sp. Musc. Frond.,
|publication year=1801
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V28/V28_355.xml
|genus=Mnium
}}<!--

-->[[Category:Treatment]][[Category:Mniaceae]]