Antitrichia Bridel, 1819.

Antitrichia californica, photo by Game

Our two species of Antitrichia are individually very easily recognized, but the macroscopic morphology is such that they may be seen as very different plants in the field. The strongly julaceous plants of A. californica grow both as lithophytes and epiphytes, and are common in mesic to geographically dry areas throughout the state. The narrowly recurved leaf margins and abruptly reflexed apiculus of this large moss make recognition certain. Antitrichia gigantea is restricted to coastal forests of high humidity and precipitation. The red stems and spreading leaves of this very large pleurocarpous moss may suggest Rhytidiadelphus loreus but the latter species has closely and regularly plicate leaves while those of Antitrichia gigantea are irregularly wrinkled or basally lightly plicate. The costae of both species of Antitrichia are flattened and thus broadened near the base, and there is usually some elaboration into accessory lateral costae. Antitrichia, like other members of its family, has sporophytes emergent from long acicular perichaetia whose leaves are several times longer than the adjacent vegetative leaves. Such strong differentiation of the perichaetial leaves provides a character that, among California mosses, is unique to the family.

Key to Antitrichia Etc.

The mosses included here are easily recognized by the plumose or wefty growth form. Some bryologists speak of dendroid mosses but we find it necessary to distinguish plumose mosses (with erect to ascending axes from which regularly arranged branches appear in a planar fashion) from dendroid mosses (with branches radiating like those of a palm tree rather than planar). We treat all our truly dendroid mosses in the key to Neckera.

The plants placed in this key have secondary branches that are at least somewhat julaceous. A number of plumose mosses have strongly complanate arrangement of the leaves of the secondary branches. These complanate and plumose plants are keyed under Neckera. Finally, the Hylocomium key deals with those plumose mosses that have leaves equally arranged around the stem but with those leaves or at least their portions spreading. All these mosses treated in the present section have relatively short and thick-walled median cells with the lumen:wall ratio seldom exceeding 5:1.

Species included in this key are in Leucodontaceae, except Bestia (Brachytheciaceae), Dendroalsia (Cryphaeaceae), Alsia (Leptodontaceae), and Pseudoleskeella (Leskeaceae):
Alsia californica (W. J. Hooker & Arnott) Sullivant
Antitrichia californica Sullivant in Lesquereux
Antitrichia gigantea (Renauld & Cardot) Kindberg
Bestia longipes (Sullivant & Lesquereux) Brotherus
Dendroalsia abietina (W. J. Hooker) E. Britton in Brotherus
Pseudoleskeella serpentinensis P. Wilson & Norris
Pterogonium gracile (Hedwig) J. E. Smith

Of special interest is the bryogeography of some of these plants. The genera Alsia and Dendroalsia are endemic to west coastal North America, and there they completely replace the globally widespread Cryphaea and Leucodon. Of additional interest is the distribution of Antitrichia (very rare in eastern United States but found in scattered localities in Eurasia and Africa) and Pterogonium (absent from eastern United States but found in Eurasia and Africa).

A. Paraphyllia present, usually densely inserted on stems and larger branches; costae single, ending above mid-leaf .....B
A. Paraphyllia absent; plants mostly julaceous; costa weak, or basally flattened and forking into subsidiary costae .....C

B. Cells strongly prorate; plant plumose and tending to curl into a ball upon drying; branch leaves conspicuously 5-ranked .....Dendroalsia: D. abietina
B. Cells smooth; plant plumose or not, never strongly distorted on drying; branch leaves not conspicuously ranked .....Alsia: A. californica

C. Cells strongly prorate; costa mostly ending near leaf middle, often distally forked; branches sometimes strongly attenuate with the entire branching system resembling a bird's foot .....Pterogonium: P. gracile
C. Cells smooth; costa mostly stronger; branches usually not strongly attenuate .....D

D. Leaves with costa extending above the leaf middle with its distal portion of costa cloaked with dorsal spines or cristae .....Bestia: B. longipes
D. Leaves with costa of various lengths but not cloaked with dorsal spines or cristae .....E

E. Leaves with costa strong and terete near base but forking distally and disappearing around mid-leaf .....Pseudoleskeella: P. serpentinensis
E. Leaves with costa flattened at the base, mostly forked at that base into supplementary costae .....F

F. Plant julaceous; cell walls little pitted; supplementary costae less than 5 cells long .....Antitrichia californica
F. Plant not julaceous; cell walls strongly pitted throughout leaf; supplementary costae much stronger .....Antitrichia gigantea