Orthotrichum kellmanii

Plants to 1 cm. Primary-stems creeping, vegetative and fertile stems erect; leaves differentiated on vegetative and fertile stems. Stem-leaves erect-appressed when dry, ovate-ligulate to ovate-oblong, grading to lanceolate or ovatelanceolate on fertile stems, 1.4–2.5 mm; margins recurved to near apex, entire; apex obtuse, acute to broadly acuminate near perichaetia; basal laminal cells quadrate to short-rectangular, walls thin, not nodose; distal cells 10–12 µm, uniformly 2-stratose, papillae 1–3 per cell, simple, low. Specialized asexual reproduction absent. Sexual condition gonioautoicous. Seta 1 mm. Capsule immersed, ovate-oblong, 1.5 mm, 8-ribbed entire length, constricted below mouth when dry; stomata immersed; peristome double; prostome absent; exostome teeth 8 splitting to 16, erect to spreading when dry, densely and coarsely papillose; endostome segments 8, occasionally rudimentary, of 1 or 2 rows of cells, smooth. Calyptra short-conic, smooth, sparsely hairy, hairs papillose. Spores 8–12 µm.

Habitat: Dry sandstone boulders in dense chaparral
Elevation: moderate elevations (600-700 m)

Calif.

Discussion

Of conservation concern.

Only two species of Orthotrichum have immersed stomata and uniformly 2-stratose distal laminal cells; Orthotrichum hallii is a species of calcareous rock found sporadically throughout western North America, while O. kellmanii occurs on sandstone boulders only at a few sites in central California. Orthotrichum kellmanii is unique in the genus because it has prostrate stems that give rise to ascending vegetative and reproductive stems, the latter with differentiated leaves compared to vegetative stems. The stomata are found in the proximal half of the capsule, mostly covered by subsidiary cells; the exostome teeth are blunt and cribrose; and the endostome segments are fragile and delicate.

Selected References

None.

Lower Taxa