Schistidium tenerum

(J. E. Zetterstedt) Nyholm

Ill. Moss. Fl. Fennoscand., Musci, 775. 1969,.

Basionym: Grimmia tenera J. E. Zetterstedt Kongl. Svenska Vetensk. Acad. Handl., n. s. 13(13): 17. 1876
Treatment appears in FNA Volume 27. Treatment on page 224. Mentioned on page 208, 219.

Plants in densely compact, usually fragile (individual stems easily separated) cushions or mats, olivaceous, brownish green, or nearly black. Stems 0.5–2 (–4) cm, central strand distinct. Leaves erect, usually imbricate when dry, ovate-triangular to ovatelanceolate, keeled distally, concave proximally, (0.7) –0.9–1.5 (–1.8) mm, usually unevenly 2-stratose distally; margins usually recurved, smooth, 1-stratose or 2-stratose; apices acute; costa usually long-excurrent as a spinulose-denticulate, usually decurrent, often flexuose awn, smooth; basal marginal cells quadrate or oblate, sometimes with transverse walls thicker than longitudinal walls, trigonous; distal laminal cells quadrate, ovate, or short-rectangular, 5–8 µm wide, smooth, weakly sinuose or straight. Sexual condition dioicous. Capsule dark reddish or orangebrown, cupulate or short-cylindric, 0.6–1.1 mm; exothecial cells isodiametric or elongate, usually thin-walled; stomata present; peristome patent to squarrose, 300–420 µm, orange or light-brown, papillose, strongly perforated. Spores 10–14 µm, verruculose.


Phenology: Capsules mature late spring to early summer.
Habitat: Exposed to semi-shaded rock, often forms rather extensive patches, especially in and along rock crevices
Elevation: low to high elevations (0-4500 m)

Distribution

V27 308-distribution-map.gif

Greenland, Alta., B.C., Man., N.W.T., Nunavut, Sask., Yukon, Alaska, Colo., Mont., Wash., Wyo., Eurasia

Discussion

The densely compact mats or cushions comprised of thin, wiry stems that readily separate once disturbed characterize Schistidium tenerum. The usually unevenly 2-stratose, ovate-triangular, small laminae tipped with long, often flexuose, spinulose-denticulate awns distinguish it from other species of the genus and similar species of Grimmia. This species is closely related to the larger S. heterophyllum, and differences between the two are discussed under that species. Probably because S. tenerum is usually sterile, many collections of it remain unidentified in collections, or identified as an undetermined species of Grimmia.

Selected References

None.

Lower Taxa

None.

"um" is not declared as a valid unit of measurement for this property.

... more about "Schistidium tenerum"
deciduous +  and persistent +
multistratose +
Terry T. McIntosh +
(J. E. Zetterstedt) Nyholm +
flexuose +
not papillose +
decurrent +  and spinulose-denticulate +
sinuous +  and straight to sometimes +
rectangular +
trigonous +, oblate +  and quadrate +
divided +
Grimmia tenera +
undifferentiated +
plicate +  and smooth +
not papillose +
mitrate +  and cucullate +
small;large +
sulcate +  and smooth +
orangebrown +  and dark reddish +
long-exserted +
striate +  and smooth +
short-cylindric;cupulate +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
thin +  and thick +
long-excurrent +
subpercurrent +
reniform +, elliptical +  and terete +
usually not markedly larger +
2-stratose +  and 1-stratose +
dioicous +  and sexual +
Greenland +, Alta. +, B.C. +, Man. +, N.W.T. +, Nunavut +, Sask. +, Yukon +, Alaska +, Colo. +, Mont. +, Wash. +, Wyo. +  and Eurasia +
low to high elevations (0-4500 m) +
elongate +  and isodiametric +
reproduction +  and asexual +
dioicous +, autoicous +  and sexual +
Exposed to semi-shaded rock, often forms rather extensive patches, especially in and along rock crevices +
papillose +, mammillose +  and smooth +
specialized +
dioicous +, autoicous +  and sexual +
concave +, keeled +, ovate-triangular +  and ovatelanceolate +
2-stratose;1-stratose;smooth +
thick-walled +  and sinuose +
papillose +  and smooth +
subtriangular +, ovate +, rectangular +  and quadrate +
thick-walled +  and sinuose +
papillose +  and smooth +
not +  and differentiated +
light-brown +  and orange +
patent +  and squarrose +
lanceolate;linear +
Capsules mature late spring to early summer. +
Ill. Moss. Fl. Fennoscand., Musci, +
straight +
sigmoid +  and arcuate +
papillose +  and smooth +
short to long +
ornamented +  and smooth +
globose +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
muticous;long-awned +
Schistidium tenerum +
Schistidium +
species +
longitudinal +  and transverse +
thicker +
black;brownish green;black;brownish green;olivaceous +