View source for Polytrichum commune

{{Treatment/ID
|accepted_name=Polytrichum commune
|accepted_authority=Hedwig
|publications={{Treatment/Publication
|title=Sp. Musc. Frond.,
|place=88. 1801,
}}
|basionyms=
|synonyms=
|hierarchy=Polytrichaceae;Polytrichum;Polytrichum commune
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Polytrichaceae]]</div><div class="higher-taxon"><small>genus</small>[[Polytrichum]]</div><div class="higher-taxon"><small>species</small>[[Polytrichum commune]]</div></div>
|volume=Volume 27
|mention_page=page 19, 22, 23, 29, 30, 31, 33, 35, 37, 92, 130, 134, 137, 1
|treatment_page=page 135
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>medium to robust, dark green to brownish with age, in loose or rather dense, tall tufts, often in extensive patches. <b>Stems</b> (2–)5–10(–70) cm, stiffly erect to decumbent, mostly simple or rarely forked, bracteate proximally, densely to rather distantly leafy. <b>Leaves</b> 6–8(–12) mm, erect or erect-spreading when dry, flexuose, with distinctly recurved tips, spreading to broadly recurved when moist, or the blade sharply squarrose-reflexed from the base; sheath oblong to elliptic, involute-tubular and clasping the stem, often golden yellow and highly nitid, abruptly contracted to the narrowly lanceolate blade; marginal lamina plane or erect, narrow, 2–3(–7) cells wide, toothed from the base of blade to the apex, the teeth unicellular, embedded in the margin; costa toothed abaxially near the apex, excurrent, ending in short, rough awn; lamellae crenulate in profile, 5–9 cells high, the margin distinctly grooved as seen from above, with 2 rows of paired, projecting knobs, the marginal cells in section narrow or more typically enlarged and wider than those beneath, retuse to deeply notched (rarely divided by a vertical partition), ± thick-walled and brownish, smooth; sheath cells 60–90 × 10–13 µm, elongate-rectangular to linear (as much as 20:1), narrower toward the margins; cells of the marginal lamina 10–15 µm wide, subquadrate. <b>Sexual</b> condition dioicous; perichaetial leaves with a long, scarious-margined sheath and blade greatly reduced, gradually narrowed to a finely acuminate tip, the margins toothed, denticulate to subentire, the costa short- to long-excurrent, roughened to almost smooth. <b>Seta</b> 5–9 cm, stout, yellowish to reddish brown. <b>Capsule</b> 3–6 mm, short-rectangular to cubic, brown to dark reddish brown, glaucous when fresh, sharply 4-alate, inclined to horizontal; peristome 250 µm, divided to 0.6, the teeth 64, pale. <b>Calyptra</b> golden yellow to brownish, completely enveloping the capsule. <b>Spores</b> 5–8(–12) µm.</span><!--

-->{{Treatment/Body
|distribution=Widely distributed in the North America;throughout temperate and boreal latitudes in the Northern Hemisphere;Mexico;Pacific Islands (New Zealand);Australia.
|discussion=<p>Widely distributed in the North America, throughout temperate and boreal latitudes in the Northern Hemisphere, Mexico, Pacific Islands (New Zealand), Australia.</p><!--
--><p>The only North American species likely to be confused with <i>Polytrichum commune</i> is <i>Polytrichastrum pallidisetum</i>. When sterile, <i>Polytrichum commune</i> is easily distinguished by cross-sections of the leaves, particularly by the greatly broadened costa, and the notched marginal cells of the lamellae. In <i>Polytrichastrum pallidisetum</i> the marginal cells of the lamellae are broadened and shallowly retuse, but not distinctly notched, and in <i>Polytrichum commune</i> the arc of guide cells (seen in section below mid-point of blade) is broad, 18–24 cells wide, compared with 8–12 cells wide in <i>Polytrichastrum pallidisetum</i>. When capsules are present, the two species can be distinguished at a glance. A striking form of <i>Polytrichum commune</i> growing in wetlands, var. uliginosum, has greatly elongate stems and tightly sheathing, glossy leaf bases, the blades are flexuose and squarrose-recurved. Recent European genetic studies (R. J. Bijlsma et al. 2000) suggest that it should be recognized as a separate species.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Plants (2-)5-10(-70) cm; apical cells of lamellae broader than those beneath, in section deeply grooved; inner perichaetial leaves not much longer than the foliage leaves, toothed distally, ending in a rather short, roughened awn
|[[Polytrichum commune var. commune|Polytrichum commune var. commune]]
|-id=key-0-1
|1
|Plants to 6 cm; marginal cells of lamellae narrow, in section shallowly grooved; inner perichaetial leaves ribbon-like, exceeding the foliage leaves, denticulate to subentire, gradually tapering to long, nearly smooth awn
|[[Polytrichum commune var. perigoniale|Polytrichum commune var. perigoniale]]
|}
</div></div><!--

-->{{#Taxon:
name=Polytrichum commune
|authority=Hedwig
|rank=species
|parent rank=genus
|synonyms=
|basionyms=
|family=Polytrichaceae
|distribution=Widely distributed in the North America;throughout temperate and boreal latitudes in the Northern Hemisphere;Mexico;Pacific Islands (New Zealand);Australia.
|reference=None
|publication title=Sp. Musc. Frond.,
|publication year=
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V27/V27_164.xml
|genus=Polytrichum
|species=Polytrichum commune
}}<!--

-->[[Category:Treatment]][[Category:Polytrichum]]