Grimmia americana

E. B. Bartram

Bryologist 32: 8, fig. 1. 1929,.

Treatment appears in FNA Volume 27. Treatment on page 232. Mentioned on page 226, 231.

Plants in hoary tufts, dark green to brown. Stems 0.5–1.5 cm. Leaves oblong-ovate to oblong-lanceolate, 1.5–2 × 0.5–0.9 mm, concave, awn to 1 mm; basal juxtacostal laminal cells quadrate to short-rectangular, straight, thick-walled; basal marginal laminal cells quadrate to long-rectangular, straight, thick-walled, medial laminal cells roundedquadrate, slightly thick-walled; distal laminal cells 2-stratose, marginal cells 2-stratose. Sexual condition gonioautoicous. Seta straight to arcuate, 0.6–1 mm. Capsule usually present, exothecial cells thick-walled, annulus of 2–3 rows of rectangular, thin-walled cells, revoluble, operculum rostellate, peristome present, fully developed, perforated and split in most distal part, weakly papillose.


Habitat: Calcareous rock
Elevation: moderate to high elevations (ca. 1600 m)

Discussion

Of conservation concern.

Grimmia americana is a rare endemic, currently known only from three sites. Until 1999, the species was known only from its type locality in Jeff Davis County of western Texas. A second locality was reported by J. Muñoz (1999) in Arizona and a third site by L. R. Stark et al. (2002) in Nevada. Thus, it is reasonable to expect G. americana to occur also in southern New Mexico. It is recognized as a member of subg. Grimmia by its immersed, ventricose capsule, with a short mitrate calyptra and eccentric seta attachment. The overall habit of the species also is similar to that of the other members of the subgenus. However, its basal laminal cells are thick-walled while other members have thin cell walls. H. A. Crum (1994c) implied that G. americana is similar to G. anodon, but the former is readily separated by its fully developed, perforated peristome, rostellate operculum, and thick-walled basal laminal cells. Grimmia crinitoleucophaea, also most commonly found in the American Southwest, is dioicous, has a rudimentary peristome, and thin-walled basal laminal cells.

Selected References

None.

Lower Taxa

None.
... more about "Grimmia americana"
deciduous +  and persistent +
well-defined +
differentiated +
Roxanne I. Hastings +  and Henk C. Greven +
E. B. Bartram +
only rarely longer +
not papillose +
toothed +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
sinuous +  and straight to sometimes +
sinuose-nodulose;quadrate;elongate +
oblate;elongate +
divided +
undifferentiated +
plicate +  and smooth +
less +  and 1/2 +
not papillose +
small;medium +
sulcate +  and smooth +
pendent +  and erect +
striate +  and smooth +
ventricose +
thin +  and thick +
thin-walled +
rectangular +
excurrent;percurrent;excurrent +
subpercurrent +
reniform +, elliptical +  and terete +
usually not markedly larger +
Ariz. +, Nev. +  and Tex. +
moderate to high elevations (ca. 1600 m) +
reproduction +  and asexual +
autoicous +  and sexual +
Calcareous rock +
papillose +, mammillose +  and smooth +
specialized +
dioicous +, autoicous +  and sexual +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
concave +, oblong-ovate +  and oblong-lanceolate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
1;multistratose +
recurved +  and incurved +
thick-walled +  and sinuose +
thick-walled +  and sinuose +
rostellate +
not +  and enlarged +
not +  and differentiated +
lanceolate;linear +
straight +  and arcuate +
arcuate +  and sigmoid +
papillose +  and smooth +
short to long +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
papillose +
globose +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
3 +  and 4 +
muticous;long-awned +
Dryptodon +  and Hydrogrimmia +
Grimmia americana +
Grimmia subg. Grimmia +
species +
4 cm40 mm <br />0.04 m <br /> (7 cm70 mm <br />0.07 m <br />) +