Schistidium heterophyllum

(Kindberg) T. T. McIntosh

Bryologist 93: 468. 1990,.

Basionym: Grimmia heterophylla Kindberg in J. Macoun and N. C. Kindberg, Cat. Canad. Pl., Musci, 64. 1892
Treatment appears in FNA Volume 27. Treatment on page 219. Mentioned on page 208, 224.

Plants in open to compact, usually fragile (individual stems easily separated) tufts or mats, olivaceous, brownish green, or nearly black. Stems 1–2.5 (–4) cm, central strand distinct. Leaves erect, rarely curved, usually imbricate when dry, ovatelanceolate to ovate-triangular, keeled distally, concave proximally, (0.8) –1.6–2.4 (–3) mm, 2-stratose distally; margins plane or erect, sometimes incurved, smooth, 1-stratose or 2-stratose; apices acute or somewhat obtuse; costa usually excurrent as a spinulose-denticulate or nearly smooth, usually straight, often very long-decurrent awn, smooth; basal marginal cells short-rectangular or quadrate, sometimes with transverse walls thicker than longitudinal walls, trigonous; distal cells quadrate, ovate, or short-rectangular, 5–6 (–8) µm wide, smooth, straight or weakly sinuose. Sexual condition dioicous. Capsule dark reddish-brown, short-cylindric or cupulate, 0.8–1.1 mm; exothecial cells isodiametric or oblate, usually thin-walled; stomata present; peristome patent, 350–550 µm, red, finely papillose, strongly perforated. Spores 10–13 µm, finely papillose.


Phenology: Capsules mature late spring to early summer.
Habitat: Rock in open to shaded habitats
Elevation: moderate elevations (300-1200 m)

Discussion

The imbricate, concave, and long-awned leaves (the concentration of awns at growing tips of the branches resemble brushes), with plane or erect margins and 2-stratose distal laminae, along with the ease by which patches fragment into individual stems, make Schistidium heterophyllum, in most cases, an easily recognized species, even though it is usually sterile. Schistidium tenerum is similar in most of these characters, but is much smaller and usually forms more compact cushions. Also, its distal laminae are unevenly 2-stratose, its leaf margins are recurved, and its awns are often strongly flexuose when dry. Where their ranges overlap in arid regions of western North America, S. heterophyllum can be easily mistaken for the macroscopically similar Grimmia laevigata. Both species are usually sterile, are of the same coloration and size, and have similar leaf characteristics. These taxa can be separated by a number of characters: the costa is pronounced on the abaxial leaf surface of S. heterophyllum and forms a distinct ridge, whereas the costa of G. laevigata is flat or only weakly raised above the laminal surface, its leaves are usually broader and not as imbricate when dry, its distal leaf cells are wider (7–9) than those of S. heterophyllum (5–6), and its leaves usually narrow considerably more to the stem base than do those of S. heterophyllum.

Selected References

None.

Lower Taxa

None.

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

... more about "Schistidium heterophyllum"
deciduous +  and persistent +
obtuse +  and acute +
multistratose +
Terry T. McIntosh +
(Kindberg) T. T. McIntosh +
straight +
not papillose +
long-decurrent +  and spinulose-denticulate +
sinuous +  and straight to sometimes +
rectangular +
trigonous +, quadrate +  and short-rectangular +
divided +
Grimmia heterophylla +
undifferentiated +
plicate +  and smooth +
not papillose +
mitrate +  and cucullate +
small;large +
sulcate +  and smooth +
dark reddish-brown +
long-exserted +
striate +  and smooth +
cupulate;short-cylindric +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
thin +  and thick +
subpercurrent +
reniform +, elliptical +  and terete +
usually not markedly larger +
dioicous +  and sexual +
short-rectangular +, ovate +  and quadrate +
2-stratose +  and 1-stratose +
B.C. +, Idaho +  and Wash. +
moderate elevations (300-1200 m) +
oblate +  and isodiametric +
reproduction +  and asexual +
dioicous +, autoicous +  and sexual +
Rock in open to shaded habitats +
papillose +, mammillose +  and smooth +
specialized +
dioicous +, autoicous +  and sexual +
concave +, keeled +, ovatelanceolate +  and ovate-triangular +
2-stratose;1-stratose;smooth +
incurved +  and erect +
thick-walled +  and sinuose +
papillose +  and smooth +
subtriangular +, ovate +, rectangular +  and quadrate +
thick-walled +  and sinuose +
papillose +  and smooth +
not +  and differentiated +
lanceolate;linear +
Capsules mature late spring to early summer. +
straight +
sigmoid +  and arcuate +
papillose +  and smooth +
short to long +
ornamented +  and smooth +
globose +
2.5 cm25 mm <br />0.025 m <br /> (4 cm40 mm <br />0.04 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
muticous;long-awned +
Schistidium heterophyllum +
Schistidium +
species +
open +  and compact +
longitudinal +  and transverse +
thicker +
4 cm40 mm <br />0.04 m <br /> (18 cm180 mm <br />0.18 m <br />) +
black;brownish green;black;brownish green;olivaceous +