Mnium thomsonii

Schimper

Syn. Musc. Eur. ed. 2, 485. 1876.

Illustrated
Treatment appears in FNA Volume 28. Treatment on page 228. Mentioned on page 223, 224.

Plants 1–2 (–7) cm. Stems reddish-brown or red. Leaves green to yellow-green, crisped and somewhat coiled around stem, slightly undulate or contorted when dry, elliptic-lanceolate, elliptic, ovate, or ovatelanceolate, 1.5–3 (–4.5) mm; base long-decurrent; margins green, occasionally brownish or reddish-brown, 2-stratose, toothed to below mid leaf, teeth variable, paired or sometimes single, small, sharp or blunt; apex acute, rounded-acute, or obtuse, apiculate or cuspidate, cusp weakly toothed or smooth, occasionally ending in long terminal cell; costa percurrent, sometimes excurrent or subpercurrent, distal abaxial surface lightly toothed or sometimes smooth; medial laminal cell shape variable, ± isodiametric or slightly elongate, (10–) 14–22 (–25) µm, slightly smaller towards margins, in longitudinal, rarely diagonal rows, not or weakly collenchymatous, blue postmortal color absent; marginal cells linear, in (1–) 2–3 (–4) rows. Sexual condition dioicous. Seta single. Capsule yellowbrown or brown, 2–5 mm; operculum rostrate; exostome greenish yellow. Spores 20–40 µm.


Phenology: Capsules mature summer.
Habitat: Calciphile, moist rock, soil, bark, along streams
Elevation: low to high elevations

Distribution

V28 364-distribution-map.gif

Greenland, Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., Que., Yukon, Alaska, Ariz., Ark., Calif., Colo., Conn., Fla., Ill., Ky., Maine, Mass., Mich., Minn., Mo., Mont., Nebr., N.Mex., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., S.Dak., Vt., Va., Wash., Wyo., Europe, Asia

Discussion

Mnium thomsonii is morphologically variable, especially in leaf shape, degree and type of marginal toothing, and costal length and toothing. Small plants often lack costal teeth and margins can be nearly smooth. However, the small laminal cells, the smallest in the genus, are diagnostic. The name M. orthorrhychum Müller Hal., often used for this taxon, is an illegitimate homonym (T. J. Koponen 1972).

Selected References

None.

Lower Taxa

None.
... more about "Mnium thomsonii"
blackish +, orange-yellow +, reddish-brown +, yellowish-brown +, yellowish green +, red +, brown +  and yellow +
cuspidate +  and apiculate +
Obtuse (?) +, Rounded-acute (?) +  and Acute (?) +
Terry T. McIntosh +  and Steven G. Newmaster +
Schimper +
red +  and yellowish +
long-decurrent +
cucullate +
brown +  and yellowbrown +
horizontal;pendent +
oblong-cylindric +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
undifferentiated +
2 (?) +  and 1 (?) +
nodulose +
excurrent +  and percurrent +
subpercurrent +
toothed +
Greenland +, Alta. +, B.C. +, Man. +, N.B. +, Nfld. and Labr. +, N.W.T. +, N.S. +, Nunavut +, Ont. +, Que. +, Yukon +, Alaska +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Fla. +, Ill. +, Ky. +, Maine +, Mass. +, Mich. +, Minn. +, Mo. +, Mont. +, Nebr. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Oreg. +, Pa. +, S.Dak. +, Vt. +, Va. +, Wash. +, Wyo. +, Europe +  and Asia +
low to high elevations +
brown +  and yellowish +
greenish yellow +
lanceolate-acuminate +
Calciphile, moist rock, soil, bark, along streams +
crowded +  and distant +
0.3 cm3 mm <br />0.003 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
green +  and yellow-green +
ovatelanceolate +, ovate +, elliptic +, elliptic-lanceolate +, contorted +, undulate +  and crisped +
larger +  and small +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
reddish-brown +, brownish +  and green +
dioicous +  and sexual +
rhomboidal +  and short-linear +
elongate +, isodiametric +  and variable +
Capsules mature summer. +
Syn. Musc. Eur. ed. +
smaller +  and larger +
diagonal +
flexuose +  and straight +
elongate +
1 cm10 mm <br />0.01 m <br /> (5 cm50 mm <br />0.05 m <br />) +
Illustrated +
spheric +
not dendroid +, branched +  and simple +
red +  and reddish-brown +
Mnium thomsonii +
species +
blunt +  and sharp +
open;compact +