Schistidium splendens T.T. McIntosh, H.H. Blom, D.R. Toren & Shevock, 2015

Blom, Terry T. Mcintosh Hans H., Toren, David R. & Shevock, James R., 2015, Two new species of Schistidium (Grimmiaceae, Bryophyta) from western North America, Phytotaxa 213 (1), pp. 57-64 : 58-60

Schistidium splendens T.T. McIntosh, H.H. Blom, D.R. Toren & Shevock sp. nov., Fig. 1

Diagnosis: Schistidium splendens is distinguished from other species of Schistidium by a number of gametophytic characters including the variable but consistent presence of 2-stratose striae in the distal and sometimes medial portions of the leaf, smooth, thick leaf margins that are recurved to near the apex (the margins are readily visible as dark lines along the leaf borders), relatively short, weakly spinulose awns that are usually non-decurrent, the strongly bulging abaxial costal surface, the relatively small laminal cells, and the often clear basal marginal cells. Distinctive sporophytic characters include the more or less isodiametric or short-elongate exothecial cells that are often irregular in shape, thin-walled, and usually with corner thickenings.

TYPE:— U.S.A. California: Lake County, Boggs Mountain State Forest, interface of volcanic and sedimentary rocks in canyon of Malo Creek . T 11N, R8W, section 7, 38º49’25’’N, 122º40’25’’W, 3000 ft, 27 May 2013, Toren, Dearing & Mullen 10061 (holotype CAS!; isotypes MO!, THR!, UBC!) .

Plants medium-sized to large, olivaceous, sometimes brownish with an orange tinge, usually shiny, forming loosely branched mats. Stems 1.0– 3.5 cm, frequently and irregularly branched, cortex thick (⅓ to ¼ thickness of stem) with small central strand. Stem leaves (1.5–) 1.8–2.2 (–2.5) mm long, ovate-lanceolate, sometimes lanceolate, often narrow, usually erect and appressed against the stem, and often weakly curved distally when dry, usually recurved, occasionally weakly spreading to patent and curved distally when wet, acutely keeled and often channeled distally, ± concave proximally, in mesic habitats 1-stratose, usually with a few 2-stratose striae distally or 2-stratose distally in wet habitats (sometimes with striae running to below midleaf), not decurrent; margins recurved to about 7/8 of the leaf, smooth, 2-, occasionally 3-stratose distally, often in 2, sometimes 3 rows, 1–2 stratose proximally, often in 2 rows; apices acute or somewhat rounded; awns usually present, short, hyaline, terete, weakly spinulose, non-decurrent except on longer awned leaves; costae percurrent, smooth, strongly bulging on abaxial surface for much of leaf length, in transverse section rounded near apex, broadened-elliptic medially and proximally, 2–3 cells thick distally, 4–6 cells thick medially and proximally; distal and medial laminal cells small, (6–) 8–9 (–10) μm wide, irregular in shape, short-rectangular or less commonly, isodiametric, occasionally oblate, walls moderately thick, usually strongly sinuose; basal cells mostly short-rectangular, thick-walled, often weakly sinuose, marginal row of cells isodiametric to short-rectangular, often clear, rarely with small corner thickenings. Perichaetial leaves (2.3) 2.5–3.2 (–3.6) mm, broadly lanceolate or ovate-lanceolate, erect, sometimes slightly curved, distal portion often abruptly narrowed and somewhat constricted, usually acutely keeled, often awned, awns similar to those on branch leaves although usually longer and more often decurrent. Sexual condition gonioautoicous. Sporophytes common, immersed; Seta (0.15–) 0.3 (–0.4) mm; Capsule light reddish-brown, cylindrical, (1.1–) 1.3–1.5 (–1.8) mm, sometimes slightly narrowed towards the mouth, shiny, occasionally striolate when dry, about 1/8 to 1/3 exposed; exothecial cells ± isodiametric or short-elongate, usually irregular in shape, often oblate, rarely in lines, thin-walled, walls sometimes curved, usually with corner thickenings; rim the same colour as capsule wall or darker and redder. Stomata present, (0) 4–6 (8) per urn. Peristome erect to patent when dry, (160–) 200 (–320) μm, reddish-brown, usually densely papillose with very short papillae, entire or sometimes lightly perforated with medial slits, with terminal prongs. Operculum flat to slightly rounded, rostrate, rostrum straight or oblique. Spores 9–10 (–12) μm, finely granulose.

Etymology: —The epithet splendens refers to beautiful appearance.

Habitat and distribution:— Schistidium splendens is viewed primarily as a semi-rheophytic species, especially in the southern portion of its range where it is often seasonally submerged or inundated during snowmelt and peak rain events along perennial and intermittent streams, often in habitats with diffuse light. However, during most of the year the plants are dry. This ecological partition of habitat along the high water zone of stream and river banks is also similar to that displayed by other western Schistidium species, primarily S. cinclidodonteum (C. Müller Hal.) B. Bremer (1980: 108) , S. occidentale (Lawton) S.P. Churchill (1981: 143) , and S. rivulare (Bridel) Podpěra (1911: 207) . Other occurrences form flat mat-like colonies over rock slabs with seasonal water flow in either intermittent watercourses or rivulets. Less commonly, small colonies are encountered on shaded boulders above the high water mark. The elevation range is from near sea level, especially in the northern portion of its range, to 7400 ft in the Sierra Nevada of California. More important than the surrounding plant community is the availability of microhabitats with periodic inundation which many Schistidium species including S. splendens prefer. To date, S. splendens is restricted to western North America, reported from California, Oregon, Washington, and British Columbia.

Comparison: — Schistidium splendens appears closely related to S. pulchrum H.H.Blom ( Blom 1996: 119). Both species have margins that are recurved to near the apex, strongly sinuose distal and medial leaf laminal cells, and similar exothecial cell areolation. However, a number of characters differentiate them. The leaf margins of S. splendens are much thicker and more evident than with S. pulchrum which have 1- or 2-stratose margins. The awns of S. splendens are usually non-decurrent and have relatively short spinulae, whereas awns of S. pulchrum are often decurrent and have longer, sharper spinulae, and the laminal cells are generally narrower and less thick-walled in S. splendens . The laminal cells of S. pulchrum , especially at mid-leaf, are often guttulate or sometimes stellate in appearance. The capsules of S. splendens are longer, 1.3–1.5 mm versus 0.8–1.3 mm in S. pulchrum . In addition, the known range of S. splendens does not overlap with S. pulchrum except possibly in British Columbia.

Additional specimens examined: — CANADA. British Columbia: Vancouver Island, Horne Lake west of Qualicum Beach , 49º21’N, 124º40’W, 15 July 1986, Schofield & Belland 84990 ( UBC) ; South shore of Rupert Inlet opposite Utah Construction , Quatsino Sound , 50º35’N, 127º23’W, 21 April 1971, Halbert & Boas 8344 ( UBC) ; U.S.A. California: Butte County: Lassen National Forest, 2 miles northeast of Concow Reservoir , 2919 ft., 30 November 2004, Dillingham & Toren 1810 &1814 ( CAS), 0.5 miles east of Sawmill Peak , 3098 ft., 2 December 2004, Dillingham & Toren 1822 ( CAS), Plumas National Forest , tributary to Lost Creek , 1.5 miles west of LaPorte , 20 July 2009, Dillingham & Toren 2606 ( CAS) ; Del Norte County: Trail to Sanger Peak north of Sanger Lake , Six Rivers National Forest , T 18N, R5E, section 29, 41º55’06’’N, 123º39’07’’W, 5500 ft., 14 June 2013, Shevock & Ma 42592 ( CAS), Knopki Creek Road toward Sanger Lake , T 18N, R5E, section 31, 41º54’56’’N, 123º40’21’’W, 4000 ft., 13 June 2013, Shevock & Ma 42577 ( CAS, UBC), Smith River near highway 199 between highway 101 and French Hill Road, 100 m, 14 November 1987, Bourell 3398 ( CAS, UBC) ; Glenn County: forest road 20N71 about 2.2 miles south by county road 308, 39º32’19’’N, 122º39’04’’W, 30 March 1997, Bourell 5843 ( CAS, UBC) ; Lake County: Crabtree Hot Springs along Rice Fork of Eel River , T17N, R9W, section 25/36 boundary, 39º17’30’’N, 122º49’30’’W, 2300 ft., 1 September 1997, Toren & Dearing 5246 ( CAS, THR), West Peak Trail , Snow Mountain Wilderness, Mendocino National Forest , T 18N, R8W, section 34, 39º22’13’’N, 122º45’07’’W, 6900 ft., 28 May 1999, Toren & Dearing 7473 ( CAS, THR), Rodman Slough, inlet of Clear Lake about 1 mile below town of Upper Lake , T 15N, R9W, section 19, 39º08’00’’N, 122º54’00’’W, 1400 ft., 26 April 2001, Toren 8697A ( CAS) ; Mt. Sanhedrin, 3 miles beyond Towhead Flat, Mendocino National Forest, T 19N, R11W, section 22, 3500 ft., 15 June 1997, Toren 5078 ( CAS) and Mt. Sanhedrin , 4000 ft., Toren 5132 ( CAS) ; Mariposa County: Moss Creek, Stanislaus National Forest , T3S, R20E, section 18, 37º40’54’’N, 119º48’36’’W, 2550 ft., 3 April 2011, Shevock & Hutten 37631 ( CAS) ; Plumas County: Plumas National Forest: Dolly Creek , 16 miles east of Quincy , 6272 ft., 15 September 2005, Dillingham Toren & Friend 2055 ( CAS), tributary to Middle Creek , 3 miles south of Antelope Lake , 5384 ft., 15 September 2005, Dillingham & Toren 2212 ( CAS), 1 mile northwest of Mt. Ararat , 5640 ft., 10 September 2004, Dillingham & Toren 1594 ( CAS) ; 2 miles south of Bucks Lake along Grizzly Creek, 5028 ft., 10 September 2004, Dillingham Toren , & Friend 1537 ( CAS), tributary to Greenhorn Creek , 5 miles east of Quincy , 3794 ft., 11 May 2004, Dillingham 1294 ( CAS), tributary of Middle Fork Feather River , 1.5 miles east of Graeagle , 4750 ft., 22 Oct 2004, Dillingham & Toren 1716 ( CAS), Dentren Creek , 1 mile east of Graeagle , 4700 ft., 1 April 2004, Dillingham 1348 ( CAS) ; San Diego County: Head of Storm Canyon, Laguna Mountains, Cleveland National Forest, T15S, R5E, section 2, 32º52’19’’N, 116º24’58’’W, 6025 ft., 27 March 2013, Shevock et al. 41941 ( CAS, UBC) ; Sierra County: Plumas National Forest, Cedar Grove Ravine , 3 miles east of LaPorte , 4745 ft., 13 Oct 2005, Dillingham & Toren 2291 ( CAS), Gibson Creek , 5.5 miles northeast of LaPorte , 5608 ft., 15 September 2005, Dillingham & Toren 2254 ( CAS) ; Siskiyou County: along forest road 4803 just below Sanger Peak Saddle, Siskiyou National Forest , T18N, R5E, section 29, 41º55’04’’N, 123º38’54’’W, 5425 ft., 14 June 2013, Shevock & Ma 42597 ( CAS, UBC), Red Rock Valley Trail, Klamath National Forest , T43N, R11W, section 17, 4800 ft., 19 September 2011, Shevock et al. 38836 ( CAS, THR) ; Yuba County: Little Oregon Creek west of county road 129 about 2 miles south of Challenge , 2700 ft., 26 June 2003, Dillingham 995 ( CAS) ; Oregon: Jackson County: Mt. Ashland , 42º14’N, 122º44’W, 18 May 1986, Schofield 84871 ( UBC) ; Multnomah County: Columbia River Gorge , 24 March 1978, Schofield & Godfrey 68189 ( UBC) ; Washington: Kittitas County: 2 miles SW of Junction of old Blewett Pass Road with highway 97, 2500 ft., 18 June 1963, Lawton 4655 ( WTU) .

Figures

FIGURE 1. Schistidium splendens. A. Habit. B. Fertile plant. C. Stem section. D. Cauline leaf. E–F. Leaf sections. G–H. Cauline leaf apices. I. Median marginal laminal cells. J. Basal laminal cells. K. Capsule in perichaetium. L. Perichaetial leaf. M. Capsule, opercula, dry. N. Capsule, wet. O. Cells at capsule mouth. Scale bar: 4 mm for A; 2 mm for B; 0.75 mm for K, M, N; 100 μm for C, E–J, O; 0.5 mm for D, L.