View source for Pseudocrossidium obtusulum

{{Treatment/ID
|accepted_name=Pseudocrossidium obtusulum
|accepted_authority=(Lindberg) H. A. Crum & L. E. Anderson
|publications={{Treatment/Publication
|title=Bryologist
|place=92: 533. 1989,
}}
|basionyms={{Treatment/ID/Basionym
|name=Barbula obtusula
|authority=Lindberg
|rank=species
|publication_title=Musc. Scand.,
|publication_place=22. 1879
}}
|synonyms={{Treatment/ID/Synonym
|name=Barbula platyneura
|authority=Macoun & Kindberg
|rank=species
}} {{Treatment/ID/Synonym
|name=Desmatodon ellesmerensis
|authority=Brassard
|rank=species
}} {{Treatment/ID/Synonym
|name=Pseudocrossidium revolutum var. obtusulum
|authority=(Lindberg) B. C. Tan, R. H. Zander & T. T. Taylor
|rank=variety
}}
|hierarchy=Pottiaceae;Pottiaceae subfam. Barbuloideae;Pseudocrossidium;Pseudocrossidium obtusulum
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Pottiaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Pottiaceae subfam. Barbuloideae]]</div><div class="higher-taxon"><small>genus</small>[[Pseudocrossidium]]</div><div class="higher-taxon"><small>species</small>[[Pseudocrossidium obtusulum]]</div></div>
|volume=Volume 27
|mention_page=page 570, 572
|treatment_page=page 571
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="stem some measurement"><b>Stems </b>to 2 cm.</span> <span class="statement" id="st-d0_s1" data-properties="leaf-stem shape;leaf-stem distance;distal margin shape or vernation"><b>Stem-</b>leaves ovate to ovate-deltoid, 0.7–1.2 mm, distal margins once to almost twice-revolute;</span> <span class="statement" id="st-d0_s2" data-properties="apex shape">apex broadly acute;</span> <span class="statement" id="st-d0_s3" data-properties="mid leaf shape;guide quantity;cell quantity">costa ending in an apiculus, adaxial surface of costa at mid leaf convex, with 2–3 guide cells;</span> <span class="statement" id="st-d0_s4" data-properties="">distal laminal cells 10–13 µm wide, 1: 1.</span> <span class="statement" id="st-d0_s5" data-properties="distal laminal cell width;distal laminal cell quantity;distal laminal cell quantity;distal laminal cell development;gemma reproduction;gemma presence;gemma shape;gemma some measurement;adaxial body architecture"><b>Specialized </b>asexual reproduction occasionally present as spheric to clavate gemmae, 40–50 µm, borne on the adaxial surface of the costa, or as rhizoid-borne brood bodies.</span> <span class="statement" id="st-d0_s6" data-properties="perichaetial leaf variability"><b>Perichaetial </b>leaves not or weakly differentiated.</span> <span class="statement" id="st-d0_s7" data-properties="seta some measurement"><b>Seta </b>1–2 cm.</span> <span class="statement" id="st-d0_s8" data-properties="capsule some measurement;peristome course;peristome architecture;tooth quantity;tooth arrangement or course or shape;tooth coloration;operculum shape"><b>Capsule </b>1–2 mm, peristome of 32 linear, yellow teeth, straight or twisted counterclockwise a half turn, operculum conic-rostrate.</span> <span class="statement" id="st-d0_s9" data-properties="spore coloration;spore architecture or pubescence or relief;spore some measurement"><b>Spores </b>yellow, essentially smooth, 8–12 µm.</span><!--

-->{{Treatment/Body
|phenology=Capsules mature in summer (Jun).
|habitat=Soil, calcareous outcrops
|elevation=low to moderate elevations 30-1100 m
|distribution=Greenland;B.C.;Nunavut;Yukon;Alaska;Calif.;Mont.;N.Mex.;Oreg.;Wash.;Europe
|discussion=<p>Pseudocrossidium obtusulum differs from P. revolutum (Bridel) R. H. Zander of Europe and Africa (absent in North America), by not or weakly differentiated perichaetial leaves, and cauline leaves ovate to deltoid, broadly acute, once-revolute, and revolute only in distal 2/3 of leaf. Discussions of the morphology and distribution of P. obtusulum in the New World have been published by G. R. Brassard (1971), P. M. Eckel et al. (1996), B. C. Tan et al. (1981), and R. H. Zander (1979). It has been collected as subfossil in the Yukon (J. A. Janssens and R. H. Zander 1980) and Vermont (N. G. Miller 1987). Fruiting material has been collected in Greenland—the peristome generally comes off with the operculum. A collection from Oregon (McIntosh 4939, UBC) has gemmae on the adaxial surface of the costa (as does P. revolutum). Didymodon brachyphyllus and D. nevadensis have somewhat the same appearance, but have merely strongly recurved distal laminal margins and an indistinct apex. This species has been collected widely in Alaska (B. M. Murray 1992), California (D. H. Norris and J. R. Shevock 2004), and Washington (T. T. McIntosh, unpubl.).</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Pseudocrossidium obtusulum
|authority=(Lindberg) H. A. Crum & L. E. Anderson
|rank=species
|parent rank=genus
|synonyms=Barbula platyneura;Desmatodon ellesmerensis;Pseudocrossidium revolutum var. obtusulum
|basionyms=Barbula obtusula
|family=Pottiaceae
|phenology=Capsules mature in summer (Jun).
|habitat=Soil, calcareous outcrops
|elevation=low to moderate elevations 30-1100 m
|distribution=Greenland;B.C.;Nunavut;Yukon;Alaska;Calif.;Mont.;N.Mex.;Oreg.;Wash.;Europe
|reference=None
|publication title=Bryologist
|publication year=
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V27/V27_820.xml
|subfamily=Pottiaceae subfam. Barbuloideae
|genus=Pseudocrossidium
|species=Pseudocrossidium obtusulum
|adaxial body architecture=rhizoid-borne
|apex shape=acute
|capsule some measurement=1mm;2mm
|cell quantity=2;3
|distal laminal cell development=specialized
|distal laminal cell quantity=1;1
|distal laminal cell width=10um;13um
|distal margin shape or vernation=2 times-revolute
|gemma presence=absent
|gemma reproduction=asexual
|gemma shape=spheric;clavate
|gemma some measurement=40um;50um
|guide quantity=2;3
|leaf-stem distance=0.7mm;1.2mm
|leaf-stem shape=ovate;ovate-deltoid
|mid leaf shape=convex
|operculum shape=conic-rostrate
|perichaetial leaf variability=differentiated
|peristome architecture=twisted
|peristome course=straight
|seta some measurement=1cm;2cm
|spore architecture or pubescence or relief=smooth
|spore coloration=yellow
|spore some measurement=8um;12um
|stem some measurement=0cm;2cm
|tooth arrangement or course or shape=linear
|tooth coloration=yellow
|tooth quantity=32
}}<!--

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