Rhizomnium glabrescens |
Rhizomnium |
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fan moss, large leafy moss, rhizomnium moss |
rhizomnium moss |
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Habit | Plants (1–)2–3 cm. | Plants 1–8(–12) cm, in tufts or mats. | ||||||||||||||||||||||||||||
Stems | reddish brown, brown, or black when old; micronemata absent. |
red or reddish brown, becoming darker, sometimes black when old, usually erect, rarely sinuate at maturity or sterile stems sometimes arching, usually simple, not dendroid; rhizoids brown, macronemata often matted proximally, mainly restricted to stem bases distally, not in longitudinal rows, micronemata present or absent. |
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Leaves | green to dark green, slightly contorted and somewhat undulate when dry, obovate or elliptic, (2.5–)4.5–6 mm; margins green or sometimes reddish or brownish, 2–4-stratose; apex rounded or occasionally obtuse or retuse, short-apiculate; costa subpercurrent or percurrent; medial laminal cells short-elongate, sometimes elongate or ± isodiametric, (35–)45–60(–70) µm, weakly or not collenchymatous, walls pitted; marginal cells linear, in 3–4(–5) rows. |
green, dark green, or occasionally reddish, reddish brown, or yellow-green, somewhat contorted when dry, erect-spreading and flat, sometimes undulate when moist, obovate, elliptic, or rarely ± orbicular, 1–7(–13) mm; base narrowly short- to long-decurrent; margins plane, green, reddish, or brown, rarely blackish with age, 1–4-stratose, entire; apex usually rounded, occasionally retuse or emarginate, sometimes apiculate; costa ending well below apex (to about 7/8 leaf length and often 2-fid distally), subpercurrent, or percurrent, distal abaxial surface smooth; medial laminal cells elongate, sometimes short-elongate or ± isodiametric, 35–180 µm, sometimes in weakly developed diagonal rows, usually collenchymatous, walls pitted or not; marginal cells differentiated, linear, rhomboidal, or rectangular, in (1–)2–3(–6) rows. |
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Seta | (2–)3–5 cm. |
single, reddish brown, occasionally orange, often pale, 1–5 cm, straight to somewhat flexuose. |
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Sexual condition | dioicous. |
dioicous or synoicous. |
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Capsule | oblong or cylindric, 3–4.5 mm; operculum conic-apiculate or conic-rostrate; exostome greenish yellow, lamellae 18+. |
horizontal to pendent, yellow or yellowish brown, elliptic, ovate, subglobose, oblong, or cylindric, 1–4.5 mm; operculum conic, conic-apiculate, or conic-rostrate; exostome yellow or brown when mature; endostome yellow or yellowish brown, segments free. |
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Spores | 30–45 µm. |
25–50 µm. |
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Specialized | asexual reproduction absent (sometimes by green protonematous rhizoids in R. punctatum). |
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Rhizomnium glabrescens |
Rhizomnium |
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Phenology | Capsules mature summer. | |||||||||||||||||||||||||||||
Habitat | Forests, logs or tree bases, moist soil near streams, thin soil over shaded rock | |||||||||||||||||||||||||||||
Elevation | low to moderate elevations | |||||||||||||||||||||||||||||
Distribution |
AK; CA; ID; OR; WA; BC
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Nearly worldwide; mostly Northern Hemisphere |
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Discussion | Rhizomnium glabrescens, common in coastal forests along the west coast, is small but distinctive. Male plants are characterized by rosettes of large leaves at the tops of the nearly naked stems. Small, scalelike leaves are present along the stem below the upper rosette. The stems of female and sterile stems have relatively large leaves. Sterile stems often arch, resembling those of Plagiomnium, but are always the same length or shorter than the fertile stems. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 13 (8 in the flora). The presence or absence of micronemata along mature stems is essential when separating species in Rhizomnium (micronemata are smaller, less branched and paler than macronemata, mainly restricted to leaf or branch bases distally). In most instances, micronemata are easy to observe, but growing stems often lack them, particularly in plants of R. magnifolium, so this character should be assessed using older stems, which are sometimes buried in the litter. Occasionally, patches of weakly developed plants of R. gracile have nearly naked stems requiring close inspection of a number of stems in order to observe the micronemata or micronemata initials. Five species of Rhizomnium are circumtemperate or circumboreal, one species is circumarctic, and two are endemic to the flora area. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 28, p. 239. | FNA vol. 28, p. 236. | ||||||||||||||||||||||||||||
Parent taxa | Mniaceae > Rhizomnium | Mniaceae | ||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||
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Synonyms | Mnium glabrescens | Mnium section rhizomnium | ||||||||||||||||||||||||||||
Name authority | (Kindberg) T. J. Koponen: Ann. Bot. Fenn. 5: 143. (1968) | (Mitten ex Brotherus) T. J. Koponen: Ann. Bot. Fenn. 5: 142. (1968) | ||||||||||||||||||||||||||||
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