Orthotrichum shevockii (Orthotrichaceae), a New Moss Species from the Southern Sierra, California

Abstract

Orthotrichum shevockii from dry granitic boulders in the southern Sierra of California is described as a new species belonging to subgen. Pulchella (Schimp.) Vitt sect. Diaphana Vent. It grows in small, dark green to blackish tufts and is characterized by having highly papillose leaf cells, bito tristratose leaf margins, immersed to shortly emergent capsules, double peristomes without prostomes, with 8 exostome teeth, and 8 or 16 endostome segments, and strongly hairy calyptra with papillose hairs. During field work in the southern Sierra in some of the driest desert areas of southern California a small, dark green to blackish Orthotrichum was collected from granitic rock outcrops. Even with a hand-lens the moss looked quite distinct and different from any North American Orthotrichum species described so far. The assumption that is was something new was further supported by microscopical studies, which for example revealed the bito tristratose leaf margins, a rare character state within the genus. Among the North American species completely or partially bistratose leaves are known from Orthotrichum strangulatum P. Beauv., O. cupulatum Brid., O. hallii Sull. & Lesq., and O. pellucidum Lindb., all members of subgen. Orthotrichum, and from O. bolanderi Sull. from subgen. Phaneroporum Delogn. The species from subgen. Orthotrichum all have erect or spreading dry exostome teeth and thus differ from the plants from the southern Sierra having the dry teeth clearly reflexed. Orthotrichum bolanderi, a species found in the dry, mountainous regions of western and central California, has the dry exostome teeth reflexed-recurved, but differs in having superficial stomata, completely bistratose leaves in the upper 23, and subsheathing leaf bases. The new species was first collected by James Shevock, phanerogamic taxonomist extraordinaire, who is opening the eyes of the junior author to the bryophyte riches of the southern Sierra in California, and is named in his honor. ORTHOTRICHUM SHEVOCKII Lewinsky-Haapasaari & Norris, sp. nov. FIGS. 1-23 O. alpestri affine, sed fuscantius et minus, papillis foliorum minoribus, capsulis profunde immersis, foliis aliquantum rigidis margines bivel tristriatos habentibus. Clos ly related to O. alpestre B.S.G., but darker and smaller, with deeply immersed to emergent capsules and rather rigid leaves with bito tristratose margins. TYPE: U.S.A. CALIFORNIA. Kern Co., along California hig way 178, 1.12 km east of Chimney Peak Road, north base of Scodie Mountains, 1,150 m, Shevock 13072 (holotype, UBC; isotypes ALTA, KUO). U.S.A. CALIFORNIA. Kern Co., off the Pacific Crest Trail about 3.6 km south of Walker Pass to fork of Jack Creek, Kiavah Wilderness, Scodie Mountains, 1,600 m, Shevock 13398, 13404 (paratypes, ALTA, KUO, UBC). Plants erect in small dark green to blackish tufts, to 1.5 cm high. Leaves spreading when moist, when dry rather rigidly erect. Leaves to 5 mm long, about 4:1, ligulate-lanceolate to elliptic-lanceolate, broadest near the middle, with obtuse to rounded acute apices. Median laminal cells isodiametric with rounded lumens, thick-walled with strong corner thickenings, to 16 psm wide, high pluri-papillose with papillar salients simple to forked, extending to 14 as high as the leaf thickness. Basal juxtamarginal cells short rectangular, 1.2-2:1, pellucid and thinwalled with corner thickenings, to 16 pm wide. Basal juxtacostal cells pellucid and short rectangular, 1.5-3:1, to 18 pLm wide with lateral walls straight but mostly with corner thickenings. Abaxial cells of costa base rectangular, 2-4:1, with forked papillae mostly restricted to the distal and proximal cell ends. Margins recurved from above the base to near the apex, mostly papillose-crenate. Costa ending within 5-10 cells of apex, distally placed in welldefined keel, in transverse section homogeneous, at mid-leaf 3-4 cells thick with about 4-5 cells on abaxial perimeter. Abaxial and adaxial cells of costa si ilar to the adjacent laminal cells. Axillary hairs to 5 cells and 150 pxm long, of essentially uniform 0007-2745/98/435-438$0.55/0 This content downloaded from 207.46.13.25 on Mon, 12 Sep 2016 04:47:32 UTC All use subject to http://about.jstor.org/terms 436 THE BRYOLOGIST [VOL. 101