Plagiobryum demissum

(Hooker) Lindberg

Öfvers. Kongl. Vetensk.-Akad. Förh. 19: 606. 1863.

Illustrated
Basionym: Bryum demissum Hooker Musci Exot. 2: plate 99. 1819
Synonyms: Meesia demissa (Hooker) Hoppe & Hornschuch
Treatment appears in FNA Volume 28. Treatment on page 154. Mentioned on page 153.

Plants 0.6–1.5 cm, red to reddish-brown. Stems 0.3–1.2 cm, innovations short, not julaceous. Leaves of innovations erect to erect-spreading, ovatelanceolate to ovate, flat to slightly concave, 0.9–1.4 × 0.2–0.5 mm; margins recurved; apex slender, acute; costa ending in apex to distinctly excurrent, in transverse-section abaxial stereid band 2–4 cells thick, 2–5 adaxial cells in 1 or 2 layers; leaves on fertile shoots more distinctly lanceolate; proximal laminal cells 3–5: 1, walls thick; medial cells narrowly hexagonal or rhomboidal to rectangular, 12–20 µm wide mid leaf, 2.5–4.5:1, walls ± firm distally. Capsule pendulous, 2–5 mm, neck 0.5–1.2 times urn length; exostome yellowish to brown, to 1/2 endostome length, nearly smooth to distinctly striate throughout. Spores released in tetrads, (26–) 28–35 (–42) µm, strongly papillose, brown.


Phenology: Capsules mature late summer–fall.
Habitat: Moist, basic cliffs, humus soil in tundra
Elevation: low to high elevations (0-4200 m)

Distribution

V28 246-distribution-map.gif

Greenland, Alta., B.C., Nfld. and Labr., N.W.T., Nunavut, Yukon, Alaska, Colo., Europe, Asia

Discussion

Plagiobryum demissum has a highly disjunct distribution that is usually associated with mountainous areas. Surprisingly, the species is rarely recorded from most areas of the Canadian Arctic. It is easily recognized when fertile by the combination of reddish gametophytes and pendulous, zygomorphic and distinctly gibbous capsules. When sterile, the plants are inconspicuous and practically indistinguishable from small reddish Bryum species.

Selected References

None.

Lower Taxa

None.

"narrower" is not a number."narrow" is not a number.

... more about "Plagiobryum demissum"
slender +
Terry A. J. Hedderson +
(Hooker) Lindberg +
2 +  and 4 +
reduced +
curved +  and straight +
decurrent +
Bryum demissum +
cucullate +
long-exserted +
gibbous +  and clavate +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
2 (?) +  and 5 (?) +
quadrate +  and long-rectangular +
appendiculate +
rudimentary +
subpercurrent +
hexagonal;rhomboidal +
Greenland +, Alta. +, B.C. +, Nfld. and Labr. +, N.W.T. +, Nunavut +, Yukon +, Alaska +, Colo. +, Europe +  and Asia +
low to high elevations (0-4200 m) +
hyaline;pale-yellow +
yellowish +  and brown +
Moist, basic cliffs, humus soil in tundra +
not +  and differentiated +
polyoicous +, monoicous +, dioicous +  and sexual +
imbricate;variously contorted +
0.9mm;1.4mm +
ovatelanceolate +  and ovate flat +
larger +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (?) +  and 0.05 cm0.5 mm <br />5.0e-4 m <br /> (?) +
rhombic +  and rectangular +
short-rectangular +  and quadrate +
0.5-1.2 times urn length +
mammillate +  and short-conic +
lateral +  and terminal +
lateral +  and terminal +
diplolepidous-alternate +
Capsules mature late summer–fall. +
Öfvers. Kongl. Vetensk.-Akad. Förh. +
differentiated +
smooth;papillose +
geniculate +  and cygneous +
lanceolate +
Illustrated +
adherent +
germinating +
not +  and julaceous +
0.3 cm3 mm <br />0.003 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
Meesia demissa +
Plagiobryum demissum +
Plagiobryum +
species +
narrow-lanceolate +
distinct +
straight +
specialized +
dioicous +, sexual +  and asexual +
sinuate +
red +  and reddish-brown +