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		University of California, Berkeley

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	photo by Wilson of Coleman 1270

Bryologist 95: 271. 1992. -- Polytrichastrum lyallii (Mitt.) G. L. Smith, Mem. N. Y. Bot. Gard. 21(3): 40. 1971. -- Polytrichadelphus lyallii Mitt., J. Linn. Soc. But. 4: 97. 1865.

Plants in loose to rather dense turfs, dark green with a brownish to blackish cast on older leaves and stems, to 5 cm high, unbranched or with innovations arising mostly lateral to the gametoecia. Leaves usually at least somewhat secund near the stem apex, lanceolate to ligulate-lanceolate, to 12 mm long, 8–10: 1, above the sheathing, ovate to obovate base, rigidly spreading when moist, becoming somewhat more erect upon drying. Elamellate lamina 2–8 cells wide; these cells more or less quadrate with angular lumens, to 15 µm wide, smooth and rather thick walled throughout or with obscure cuticular ridges. Cells of sheathing portion of leaf rather thick walled, roughly rectangular but with curving lateral walls and oblique end walls, to 15 µm wide. Marginal cells of the distal portion of the sheathing base hyaline and very thin walled, often collapsing. Cells of basal margin of limb at shoulder transversely elongate in a large and dark patch, very thick walled with lumen: wall ratio 1/3–1/2: 1. Margin plane, entire below but coarsely dentate above the shoulders with teeth formed of cells much enlarged relative to adjacent laminal cells. Costa excurrent in a short acuminate spine. Photosynthetic lamellae 35–50, mostly straight in dorsal view, 4–6 cells high, with the terminal cells enlarged, elliptic to pyriform in cross-section, with longitudinal grooves or ridges on the thickened distal wall. Costa cross-section with two strongly developed stereid bands but with the adaxial layer quite narrow, and with one or two layers of guide cells. Axillary hairs hyaline throughout, to 800 µm long, inserted on each of the basal cells of the leaf. Rhizoids white to pale yellow, sparsely branched, to 10 µm broad at base, sparsely to rather densely inserted on otherwise undifferentiated cortical cells primarily on the stem base. Stem cross-section rounded triangular, with a very well defined central strand; with somewhat leptodermous inner cortical cells; and with strongly pachydermous outer cortical cells.
    Dioicous with male plants smaller than the females. Perichaetia and perigonia terminal, with the latter forming prominent splash-cups. Perichaetial leaves not much differentiated from adjacent vegetative leaves. Consistently monosetous with setae red brown, smooth, to 6 cm high, straight. Urn to 4 mm long, about 2: 1, cylindrical, slightly curved to twisted, broadest near the base, longitudinally ridged mostly with 4 asymmetrically placed, sharply defined ridges. Operculum curved and rostrate, to 1/3 of urn length, flaring but not flat-topped at base of rostrum. Exothecial cells to 30 µm broad, irregularly rectangular with thick lateral and transverse walls, isodiametric to transversely elongate in 3–6 rows at mouth of capsule. Stomates present on constricted base of urn. Peristome teeth 64, cellular, papillose, hyaline on margins but with a central spine of 2–4 red brown cells. Epiphragm present, seemingly attached near the tips of the peristome teeth, rather thick and chambered, peripherally fringed with tooth like appendages. Calyptra cucullate, covering the urn, mostly sparsely hairy. Spores green, nearly smooth, about 12 µm in diameter.

Elevation by latitude plot for Meiotrichum lyallii
   in California

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