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|Pleuridium subulatum (Hedwig) Rabenhorst [Ditrichaceae]|
Mail a correction to Paul Wilson
Deutschl. Krypt.-Fl. 2(3): 79. 1848. -- Phascum subulatum Hedw., Spec. Musc. 19. 1801.
Pleuridium bolanderi C. Muell. ex Jaeg., Ber. St. Gall. Naturw. Ges. 1868–1869: 91. 1869.
Plants to 2 mm high in dense turfs or scattered, yellow-green to olive-green. Leaves erect spreading to patent wet or dry, often somewhat falcate secund, to 2 mm long, very narrowly subulate from an ovate base which comprises less than 1/2 of the leaf. Median cells of subula rectangular with rather thick walls, smooth, to 6 µm broad, 3–5: 1, in regular rows. Cells of differentiated base to 8 µm broad, to 10: 1, rectangular with straight lateral walls, arranged in regular rows. Costa occupying about 1/5 of leaf base, gradually tapering and strongly excurrent in the terete subula. Costa cross-section nearly homogeneous or with a single abaxial stereids differentiated from the adaxial guide cells. Margin mostly with a few bistratose streaks, plane to incurved, entire throughout or with a few remote serrulations near apex. Axillary hairs to 150 µm, 3-celled, with one basal brown cell. Stem with central strand, very thin walled throughout except for a one or two layers of thicker waller, much smaller outer cortical cells.
Autoicous with antheridia naked and axillary below the perichaetia. Perichaetial leaves similar to the adjacent vegetative leaves but with subula not so well defined. Seta nearly absent. Capsule cleistocarpous, yellow brown to stramineous, to 1.25 mm long, oblong and apiculate, about 1–1.2: 1, symmetric. Operculum conic, to 1 mm long. Exothecial cells rectangular, arranged in regular rows, to 18 µm wide, to 3: 1, rather thin-walled. Stomata restricted to proximal 1/2 of urn. Spores coarsely papillose, to 25 µm.
Pleuridium subulatum is widely distributed throughout temperate regions of Eurasia, North Africa and North America. It is the only common species of Pleuridium in California and is extremely common in winter and early spring wherever there is enough rain to support grasses. In our state it is extremely variable in shape of leaves, especially the relative length of the base and the subula. The variation in plant color and degree of clone aggregation is also so great as to suggest a need for serious comparative study.
|Literature||Bradshaw 1926; Crum and Anderson 1981; Kellman 2003; Lawton 1971; Lesquereux 1868; Shevock and Toren 2001; Sigal 1975; Watson 1880; Yip 2000, 2002; Yurky 1990, 1995. As Pleuridium alternifolium var. howei Renauld and Cardot 1893.|
|Illustrations||Malcolm et al. 2009 p. 93; Crum and Anderson 1981; Ignatov and Ignatova 2003; Ireland 1982; Lawton 1971; Sharp et al. 1994; Smith 1978; Yip 2000.|
|Bioregions||CaR, CW, GV, NW, SN.|
|Vouchers||Butte Co.: Neal Road south of Chico to Paradise about 0.5 mile east of Highway 99, Norris 10611a (determined by Yip); Del Norte Co.: French Hill, Six Rivers National Forest, Harpel 3166 (pers. herb.); Fresno Co.: Sycamore Flat Campground, Pine Flat Reservoir, Sierra National Forest, Norris 50970; Lake Co.: Highway 175 at Loch Lomond along edge of swamp near Hobergs, Toren 7444 (CAS) [determined by Yip]; Marin Co.: Temelpa Trail, Mt. Tamalpais State Park, Yurky 537 (SFSU); Santa Cruz Co.: Henry Cowell State Park, Kellman 594 (CAS).|