Pseudocrossidium Obtusulum (Pottiaceae, Bryopsida) New to Montana with a Key to North American Species in the Genus
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Great Basin Naturalist Volume 57 Number 3 Article 9 7-31-1997 Pseudocrossidium obtusulum (Pottiaceae, Bryopsida) new to Montana with a key to North American species in the genus P. M. Eckel Buffalo Museum of Science, Buffalo, New York J. A. Hoy Stevensville, Montana J. C. Elliott Conservation Biology Research, Helena, Montana Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Eckel, P. M.; Hoy, J. A.; and Elliott, J. C. (1997) "Pseudocrossidium obtusulum (Pottiaceae, Bryopsida) new to Montana with a key to North American species in the genus," Great Basin Naturalist: Vol. 57 : No. 3 , Article 9. Available at: https://scholarsarchive.byu.edu/gbn/vol57/iss3/9 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Great Basin Naturalist 57(3), © 1997, pp. 259-262 PSEUDOCROSSIDIUM OBTUSULUM (POlTIACEAE, BRYOPSIDA) NEW TO MONTANA WITH A KEY TO NORTH AMERICAN SPECIES IN THE GENUS P.M. Eckel!, I.A. Hoy2, and I.G. Elliott3 ABSTRACf.-The moss species Pseudocrossidium obtusulum (Lindb.) Crum & Anderson is reported for the state of Montana. Recent systematics ofthe genus Pseudocrossidium in North America is discussed. Key words: nwsses, hryophytes, Montana, Pseudocrossidium, P. crinitum, P. homschuchianum, P. obtusulum, P. replica tum, P. revolutum. Montana has one of the richest recorded checklist (Anderson et al. 1990), but without moss floras of the western United States, with discussion. Zander (manuscript in preparation) 410 known species and varieties (Elliott in has determined that E revohaum does not occur preparation). Although most collecting has in the Arctic or Greenland, or elsewhere in occurred in the western portion of the state, a North America. Because one of the obstacles to concentrated examination of particularly dry the convenient study ofarid bryophyte crypto habitats in Ravalli County has yielded species floras is the scattered taxonomic treatments, new to the state (Eckel, Hoy, and Elliott in an attempt has been made here to summarize preparation). These species are members of a the genus to date in North America with a key cryptoflora ofminute bryophytes occurring on and illustrations to the 5 species. various soil substrates, ofwhich one is the fol Historically, species in the genus Pseudo lowing species: crossidium have been placed in the genera Barbula Hedw., Desmatodon Brid., and Tor Pseudocrossidium obtusulum tula Hedw. However, most are distinguishable (Lindb.) Crum & Anderson from these genera by the strongly and strik USA, Montana, Ravalli Co., east side of Bit ingly revolute leaf margins, most evident on terroot Valley, North Birch Creek watershed: 7 transverse sections of the leaf, resembling 2 miles SSE of Stevensville, NW NE Sec. 12, cylinders separated by a groove (Zander per T7N, R19W, 3600' elev., from vertical S-facing sonal communication) as opposed to the usual cliff face, N side of irrigation ditch just above plain or narrowly recurved leaves of other old water level; Hoy 306, April 6, 1996 (BUF). species ofother genera. The character of differ There are 5 species of Pseudocrossidium entiated pericbaetial leaves may differentiate Williams presently listed in the moss flora of the genus in the broadest sense, especially North America north of Mexico (Anderson et al. species in South America where the bulk of 1990). Spence (1987) has given a good review the species occur; but for the 4 taxa occurring of the literature and American distribution of in North America (here excluding E revolu 4 of these, the 5th being E obtusulum (Lindb.) tum), only E hornshuchianum has such-a Crum & Anderson, a species considered by species found to date in North America in only some to be a variety of E revolutum (Brid. in 2 botanical gardens, 1 in British Columbia (Tan Schrad.) Zand. (Tan et al. 1981), and by others et al. 1981), the other in Massachusetts (Mishler to be indistinguishable from the latter in local and Miller 1983). populations in the field (McIntosh 1986). The The genus is separated from Barbula and variety was elevated to species status by Crum other genera ofthe Barbuloideae, such as Didy and Anderson (1989) for the North American madon, by the absence of a ventral stereid IClinton Herbarium, Buffalo Museum ofScience, Buffalo, NY 14211. 22S58 PheMant Lane, Stevensville, MT 59870, 3Conservation Biology Research, 835 Eighth Avenue, Helena, MT 59601, 259 260 GREAT BASIN NATURALIST [Volume 57 band in the costa. Neither Desmatodon nor Pseudocrossidium revolutum is a European Tortula has this feature eithel; or it is occasion species with oblong-lanceolate to ligulate upper ally weakly present. McIntosh (1986) has also leaves, more strongly and more narrowly revo pointed out the useful character of the sharp lute margins extending nearly to the leaf base, and deep costal groove or keeled leaf in Pseudo margins as seen in section 11/2 times revolute crossidium, whereas in Tortula and Desma with leaves strongly twisted and inrolled when todon the leaf is broadly channeled and the dry. The leaf mucro is not stout and is shorter costa in section is nearly circular with an ele than in P obtusulum, whose leaves are imbri vation, sometimes distinctive, on the ventral cated or only somewhat twisted when dry. The surface composed ofdifferentiated cells. Zander perichaetial leaves are strongly differentiated (1993) has indicated that the crescent-shaped in P revolutum and there is no record of pro dorsal stereid band, as opposed to the semicir pagula in this species, whereas the perichaetial cular band of Desmatodon and Tortula, is dis leaves of the occasionally gemmiferous P. ob tinctive in Pseudocrossidium. tusulum are weakly differentiated or undiffer McIntosh (1986) has also distinguished P. entiated. obtusulum (as P. revolutum) from Didymodon Pseudocrossidium obtusulum is rare in the brachyphyllus (Sull. in Whippl.) Zand., a species Arctic (Zander in preparation) but distributed sometimes associated with P. obtusulum, by from Greenland, the Northwest Territories, and the dense papillae, as well as the lack of ven Alaska south to the Yukon, British Columbia, tral stereid band. Tortula muralis Hedw. and Oregon, and southern California just north of its closely related if not synonymous species, the Mexican border (map in Tan et al. 1981). Tortula brevipes (Lesq.) Broth. and Desmatodon In an extensive dry-steppe vegetational study plithobius Sull. & Lesq., also have broadly spi by Melntosh (1986), the species was reported rally once-revolute margins and densely papil as locallv, common in the interior of British lose leaves, but usually have a rather long, Columbia. The Montana station is an inland smooth awn. Tiny specimens may, however, be extension of its previously recorded range, only mucronate and are distinguished from P. Melntosh's description of the area as the Cor obtusulum by the latter's flattened, crescent dilleran steppe or shrub-steppe is extended shaped dorsal stereid band. eastward to southern \Vyoming and Colorado, Key to Pseudocrossidium Species in based on Daubenmire (1978). The area of the North America and Greenland collections presently reported also represents the steppe conditions as characterized in (Figs. 1-5) Melntosh's south central British Columbia L Leaves short- to long-awned: study. It is probably also controlled by the 2. Leaves rounded-obtuse at base of long awo; rain-shadow effect of the western mountains, ventral costal surface concave; guide cells 4; No rhizoidal tubers as described and illus Mexico, Arizona, New Mexico, Texas, Utah ... · Pseudocrossidium crinitum (= P. aureum) trated by Tan et al. (1981) were observed in 2. Leaves acute at base of short-awn; ventral the Montana collections. costal surface convex; guide cells 2; botanic As to Pseudocrossidium obtusulum beloug gardens in British Columbia and Massachusetts ing to floristic elements with distinctive distri · Pseudocrossidium hornschuchianum bution patterns, the reports of P. revolutum 1. Leaves merely apiculate to short-mucronate: by McIntosh as a western North American 3. Leaves relatively long, 1.0-1.5 mm, ligulate to Eurasian species must be revised as P. revolu oblong-lanceolate, apex obtuse; ventral costal tum has been excluded from the North Ameri surface concave; guide cells (4-) 6; margins can flora. That species would now be character strongly spirally revolute, inrolled margins of ized as a Eurasian species. Pseudocrossidium bright green thin-walled cells with hollow papillae. without propagula; Mexico, SW USA obtusulum would then belong to Melntosh's · .... , ... ,., ... ,.,. Pseudocrossidium replicatum western North American-western Eurasian 3, Leaves relatively short, 0.7-1.2 mm, ovate to element, since this species occurs from the ovate-deltoid, apex broadly acute; ventral costal Arctic to southern California and 2 stations in surface convex; guide cells 2-3; margins revolute what one might expect to be temperate steppe 1 time, ofundifferentiated cells, sometimes with conditions in central Germany and southern rhizoidal and costal propagula; southern Cali fornia, American NW; Arctic, and Greenland .. Sweden (Tan et al. 1981). Schofield (1980) dis ,.,,.,, .. ,,.,, ..... Pseudocrossidium obtusulum cusses the disjunct flora of western North