Grimmia reflexidens
Grimmia lesherae
1–2 cm, central strand absent.
0.5–1.5 cm, dichotomously branched, central strand absent.
absent.
ovate to oblong-lanceolate, 0.1–1.15 × 0.3–0.5 mm, keeled, not plicate, margins plane, awns 1–2 mm, very long, smooth to slightly denticulate, flattened basally, long-decurrent, costal transverse section prominent, semi-circular;
basal juxtacostal laminal cells rectangular, sometimes nodulose, thin- to thick-walled;
basal marginal laminal cells rectangular with thickened transverse walls, pellucid in 2–4 rows;
medial laminal cells rounded-quadrate, slightly sinuose, thick-walled;
distal laminal cells yellowish green, 1-stratose with 2-stratose ridges, not bulging, marginal cells 2-stratose, not bulging.
loosely appressed and straight when dry, erectopatent when moist, broadly oblong-lanceolate, tapering to acute apex, 1.5–2 × 0.4–0.6 mm, larger towards stem tips, sharply keeled, margins recurved on both sides, awns absent, occasionally short hyaline points at leaf tips present, costa weak proximally, broad distally, projecting on abaxial side;
basal juxtacostal laminal cells rectangular to linear, straight, thin-walled;
basal marginal laminal cells rectangular, thin-walled;
medial laminal cells short-rectangular with nodulose to sinuose walls, weakly papillose;
distal laminal cells 1-stratose, margins 2-stratose.
straight, 2 mm.
dioicous, perichaetial leaves enlarged.
dioicous.
absent in northern hemisphere material, emergent to shortly exserted, yellowish brown, oblate, exothecial cells irregularly short-rectangular, thin-walled, stomata absent, annulus of 1 row of quadrate, thick-walled cells, operculum mammillate to rostrate, peristome present, nearly fully-developed, split and perforated only in apex, papillose.]
occasionally present, exserted, yellowish brown, oblate, smooth, exothecial cells thin-walled, annulus present, operculum rostrate, peristome teeth orange, deeply split and perforated, papillose.
cucullate.
Grimmia reflexidens
Grimmia lesherae
Of conservation concern.
Previous to its discovery in Iceland, as Grimmia grisea (H. C. Greven 1998), G. reflexidens was known from only the Southern Hemisphere. It had previously been collected east of East Bay, Newfoundland, now the only known locality in North America, but was not recognized as G. reflexidens. The latter is similar to G. asperitricha Dixon & Sainsbury of New Zealand, and the two species have been confused by G. O. K. Sainsbury (1945) as well as by R. Ochyra (1993). J. Muñoz (1998b) synonymized G. reflexidens with G. sessitana. However, the former is readily separated from the latter by: (1) enlarged perichaetial leaves, (2) decurrent awns, (3) non-bulging laminal cells, and (4) dioicous sexual condition. Capsules are unknown from Northern Hemisphere material, but G. reflexidens lacks stomata while they are present for G. sessitana. Although G. reflexidens and G. teretinervis both have decurrent awns they are easily separated by a number of characters: G. reflexidens grows in compact cushions, has long awns, and a semicircular costa; G. teretinervis grows in loose clumps, is hyaline-tipped to short-awned, and has a unique costa that is distally almost completely circular in transverse section.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Grimmia lesherae is apparently endemic to the high mountains along the Pacific Coast of western North America. At present, it is known only from a few damp high elevation sites in Washington and northern California, but suitable habitats exist all along the high coastal mountains and so it may also be expected in Oregon. It is a distinctive species that is unlikely to be confused with others. There are some similarities to G. incurva, but that species has short hair-points, the leaves are linear, the medial cells have nodulose walls, and the seta is arcuate. The combination of keeled leaves with recurved margins, and straight seta is unique in the subgenus. Grimmia lesherae appears to be intermediate between subg. Guembelia and subg. Rhabdogrimmia, calling into question the division of the genus into four subgenera. A peculiar distinguishing character is the left-handed twist of dried-up setae, unique in the genus. K. G. Limpricht ([1885–]1890–1893, vol. 1) incorrectly reported the left-hand twisted, dried up setae as common in Grimmia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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