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hornschuch's beard-moss, hornschuch's pseudocrossidium moss

Stem(s)

leaves ovate to short-lanceolate, 1.5–1.9 mm including the awn, distal margins strongly recurved to once revolute;

apex rounded-obtuse below the awn;

costa ending in a short awn, adaxial surface of costa at mid leaf concave, with 4 guide cells;

distal laminal cells 12–15 µm wide, 1:1.

leaves ovate-deltoid to short-lanceolate, 1–1.5 mm, distal margins once- to almost twice-revolute;

apex narrowly acute below the awn;

costa ending in the long mucro or short awn, adaxial surface of costa at mid leaf convex, with 2–3 guide cells;

distal laminal cells 10–13 µm wide, 1:1.

Seta

ca. 1 cm.

Capsule

ca. 1.7 mm, peristome of 32 linear, yellow teeth, twisted counterclockwise a half turn, operculum conic.

Spores

yellow, essentially smooth, 8–10 µm.

Specialized

asexual reproduction absent.

asexual reproduction absent.

[perichaetial leaves not differentiated.] sporophytes not seen.

Perichaetial

leaves strongly differentiated.

Pseudocrossidium crinitum

Pseudocrossidium hornschuchianum

Habitat Soil, sand, sandstone, limestone, basalt, shale, boulders, ledges, deserts Thin soil, lawns, limestone, bluff overlook, gardens, rock outcrop, ridge top
Elevation moderate to high elevations (500-2000 m) (moderate to high elevations (1600-6600 ft)) low to moderate elevations (20-700 m) (low to moderate elevations (100-2300 ft))
Distribution
from FNA
AZ; NM; NV; TX; UT; Mexico; South America; Africa; Australia
[WildflowerSearch map]
from FNA
MA; OR; BC; Eurasia; Africa; Australia
Discussion

Pseudocrossidium crinitum, when the awn is short, can be distinguished from P. replicatum (forms of which may have strongly mucronate leaf apices) by the large area of differentiated parenchymatous cells on the abaxial lateral surface of the costa on both sides adjacent to the laminal insertion on the costa, easily seen in section at mid leaf and often deep yellow in color, appearing as a row of ocelli; the leaf marginal cells are very thin-walled. This essentially southern species reaches its northern range extension in western United States E. B. Bartram 1924; R. H. Zander 1993). An exceptionally robust collection of P. crinitum from Mexico (Puebla, Azumbilla, Zander 4899, BUF) has two layers of guide cells in the costa, but this is very unusual.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Pseudocrossidium hornschuchianum was first reported for North America from British Columbia by B. C. Tan et al. (1981), then from Massachusetts by B. D. Mishler and N. G. Miller (1983), apparently associated with ornamental cultivation. The Oregon station (Jackson County, Ferris Gulch, D. H. Wagner 9183, MO) is apparently, however, in a natural setting on a ridge top. This species differs from P. obtusulum by the narrowly acute apex with a long apiculus or short awn, and the strongly differentiated perichaetial leaves. Both perigoniate and archegoniate plants are present in the West (British Columbia), though at different sites, and the Oregon specimen was fruiting, while only perichaetiate plants are found in the East (Massachusetts).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 27, p. 570. FNA vol. 27, p. 572.
Parent taxa Pottiaceae > subfam. Barbuloideae > Pseudocrossidium Pottiaceae > subfam. Barbuloideae > Pseudocrossidium
Sibling taxa
P. hornschuchianum, P. obtusulum, P. replicatum
P. crinitum, P. obtusulum, P. replicatum
Synonyms Barbula crinita, Barbula aurea, P. aureum, Tortula aurea Barbula hornschuchiana
Name authority (Schultz) R. H. Zander: Bull. Buffalo Soc. Nat. Sci. 32: 119. (1993) (Schultz) R. H. Zander: Phytologia 44: 205. (1979)
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