Plants light green to rather deep green, to 6 mm high, with up to 10 pairs of leaves. Leaves, when dry, laterally twisted; when moist, spreading from stem at about a 30 degree angle, to 2 mm long, 3–4: 1 oblong to oblong lingulate. Vaginant lamina to 5:1, extending about 1/2 of leaf, the two sides converging at an acute angle, homostichous. Dorsal lamina mostly tapered to extinction above the leaf base, not decurrent. Median cells of apical and dorsal laminae unistratose, smooth, to 12 µm wide, thin-walled, hexagonal to rhomboidal with angular lumens and no corner thickenings. Median cells of vaginant lamina somewhat more regularly arranged, mostly a little longer than wide, 1–2:1, to 12 µm wide. Basal juxtacostal cells somewhat larger and more elongate. Costa to 25 µm at base, percurrent to subpercurrent, sometimes merging with limbidium at apex and forming an apiculus. Margin plane and entire throughout. Limbidium variably present, extending to apex or ending several cells below apex, occasionally almost absent from dorsal lamina. up to 4 cells wide, without stereids, not at all decurrent. Stem with no central strand and with a few thin-walled inner cortical cells abruptly differentiated from 1–2 layers of smaller, rather thick-walled outer corticals; lateral cells of outer cortex poorly differentiated. Axillary hyaline nodules not present.
Dioicous or autoicous. Perichaetia terminal with seta to 8 mm, red-brown, nearly straight above the geniculate base, smooth. Urn to 0.8 mm long, oblong and symmetrical, about 2: 1. Operculum conic, about 1/3 as long as urn. Calyptra cucullate, smooth. Peristome reddish-brown, to 250 µm long, minutely papillose proximally, spirally ridged distally. Exothecial cells in regular vertical rows, somewhat bulging on outer surface, mostly isodiametric with angular lumens, rather thin-walled, to 15 µm wide. Spores to 20 µm, finely papillose.
| Literature | Kellman 2003; Pursell 1997b; Shevock and Toren 2001. As Fissidens limbatus Brandegee 1891; Flowers 1973; Harpel 1980a; Harthill et al. 1979; Kingman 1912; Koch 1949a, 1950a; Koch and Ikenberry 1954; Lesquereux 1868; Lesquereux and James 1884; Long 1978; McCleary 1972; Millspaugh and Nuttall 1923; Mishler 1978; Moxley 1928, 1931; Sayre 1940; Sigal 1975; Steere 1954; Sullivant 1856; Toren 1977; Watson 1880; Whittemore and Sommers 1999; Yurky 1995. |
| Illustrations | Malcolm et al. 2009 p. 84; Flowers 1973; Sharp et al. 1994. |
| Bioregions | CaR, CW, GV, NW, SN, SW. |
| Vouchers | Colusa Co.: about 1.2 miles east of Sites, Norris 72681; Fresno Co.: Cripe Road, 0.65 mile from Peterson Mill Road, Sierra National Forest, Shevock & York 14949 (confirmed by Pursell); Kern Co.: Bodfish-Havilah Road, 0.5 mile south of Bodfish Gap, base of Piute Mountains, Shevock & Tan 13041 (determined by Pursell): Lake Co.: Highway 53 about 1 mile south of Highway 20, Norris 47703; San Francisco Co.: Mt. Sutro, Shevock 19175 (determined by Pursell); Santa Barbara Co.: Lobos Canyon, Santa Rosa Island, Channel Islands National Park, Shevock & Rodriquez 20855 (determined by Pursell); Tehama Co.: end of Buckhorn Road, BLM Black Butte Recreation Area, Norris & Piippo 82376; Tulare Co.: about 0.5 mile above Buckeye Campground, trailhead for Middle Fork Kaweah River Trail, Sequoia National Park, Shevock 15212 (determined by Pursell). |
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