Plagiomnium cuspidatum |
Plagiomnium |
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baby tooth moss, tooth plagiomnium moss, woods leafy moss, woodsy mnium |
plagiomnium moss |
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Habit | Plants (1–)2–5(–10) cm, dense or open mats. | |||||||||||||||||||||||||||||||||||||||||
Stems | green or yellow-green, usually brownish with age; stems of two types, fertile stems erect, branching distally or not, dendroid or not, sterile stems plagiotropic or arching, rarely erect, to 20 cm; rhizoids brown, macronemata mainly proximal, occasionally along underside of sterile stems, micronemata present. |
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Leaves | dark green or yellow-green, contorted when dry, flat when moist, obovate, ± diamond-shaped or occasionally elliptic, 3–5 mm; base broadly long-decurrent; margins toothed from about mid leaf to apex, teeth sharp, of 1 (or 2) cells; apex acute or acuminate, long-cuspidate, cusp sometimes toothed; costa percurrent or excurrent; medial laminal cells short-elongate or ± isodiametric, 20–30(–40) µm, slightly smaller near margins, occasionally in longitudinal rows, rarely in diagonal rows, strongly collenchymatous, walls not pitted; marginal cells linear, in 2–4(–5) rows. |
green or yellow-green, rarely black with age, variously crisped or contorted when dry, erect-spreading, usually flat, occasionally irregularly wavy or transversely undulate when moist, elliptic, obovate, oblong, oblong-lingulate, oblong-elliptic, or rarely orbicular or diamond-shaped, 1–14 mm; base decurrent or not; margins plane, green or yellow-green, 1-stratose, toothed, often to near base, sometimes only distally, rarely entire, teeth single, sharp or blunt, of 1–2(–4) cells, rarely hooked; apex acute, acuminate, obtuse, rounded, truncate, retuse, or emarginate, mucronate, apiculate, or cuspidate, cusp toothed or not, rarely bent to one side; costa percurrent, excurrent, or rarely subpercurrent, distal abaxial surface smooth; medial laminal cells short-elongate, elongate, or ± isodiametric, (15–)30–70(–85) µm, sometimes in diagonal or longitudinal rows, collenchymatous or not, walls pitted or not; marginal cells differentiated, linear or rhomboidal, in 2–4(–5) rows. |
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Seta | single, yellow, brown, or sometimes reddish, 2–3 cm. |
single or multiple, yellow, yellow-green, brown, sometimes reddish or greenish, rarely orange, dark red, or blackish with age, 1.2–5 cm, straight to flexuose. |
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Sexual condition | synoicous. |
synoicous or dioicous. |
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Capsule | pendent, ovoid or cylindric, 2–3.5 mm, neck not distinct; operculum conic-apiculate. |
horizontal to pendent, yellow or yellowish brown, cylindric, oblong, oblong-cylindric, obovoid, or ovoid, 1.5–5 mm; operculum conic-apiculate or rostrate; exostome yellow or brown; endostome yellow to yellowish brown. |
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Spores | 18–31 µm. |
18–40 µm. |
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Erect | stems 1–2(–3.5) cm, not dendroid; sterile stems to 7 cm. |
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Specialized | asexual reproduction usually absent (by stolonlike stems in P. undulatum). |
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Plagiomnium cuspidatum |
Plagiomnium |
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Phenology | Capsules mature late spring. | |||||||||||||||||||||||||||||||||||||||||
Habitat | Soil, logs, rock, stumps or tree bases in wet meadows/carrs, forested rich peatlands, wet forests, fire-dependent forests/woodlands, mesic hardwood forests, cliff/talus | |||||||||||||||||||||||||||||||||||||||||
Elevation | low to moderate elevations | |||||||||||||||||||||||||||||||||||||||||
Distribution |
AK; AL; AR; CA; CO; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; AB; BC; MB; NB; NL; NS; ON; PE; QC; SK; Asia; Greenland; Europe; Mexico (México); Africa
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Nearly worldwide |
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Discussion | Plagiomnium cuspidatum, P. drummondii, and P. floridanum are the only North American species of the genus that consistently have well-developed, sharp teeth restricted to the distal portions of the leaf margins. Plagiomnium ellipticum and P. rostratum often have leaves that are toothed only distally, but the teeth are small and mostly blunt, and the leaves are never obovate. Plagiomnium cuspidatum has larger leaves and larger, less collenchymatous laminal cells than P. drummondii and P. floridanum. The thinner cell walls and larger cells of P. drummondii give it a distinctly more translucent aspect than P. cuspidatum and P. floridanum. In addition to the morphological characters in the key, Plagiomnium cuspidatum is separated from the closely allied P. floridanum by sexual condition, ploidy level, and ecology (R. Wyatt and I. J. Odrzykoski 2012). Plagiomnium cuspidatum is synoicous and diploid, with a chromosome count of n = 12, whereas P. floridanum is dioicous and haploid, with a chromosome count of n = 6. Although Plagiomnium cuspidatum exhibits a relatively broad ecological amplitude, P. floridanum shows a preference for soils associated with limestone. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 26 (11 in the flora). Plagiomnium is characterized by singly serrate, 1-stratose leaf margins, the absence of red stem tissue, and, in most species, the production of long sterile plagiotropic or arching stems. Plagiotropic stems are absent in P. venustum and some fertile patches of a few other species, in particular P. insigne. In many Plagiomnium populations, fertile stems are absent with plagiotropic stems producing vegetative mats over and among litter and other mosses. Morphological variation is common in Plagiomnium and has led to misidentifications in regional herbaria. Many characters that have been used in extant keys, such as sharpness, size, and cell composition of marginal teeth, presence and length of leaf decurrencies, and degree of laminal cell pitting, can vary within and between populations. Extant keys often use sexuality to separate species; unfortunately, many collections are sterile, and this character is of little use. As with Brachythecium, sterile collections of Plagiomnium may be unidentifiable, especially weakly developed plants from wetland habitats. Based on the review of the collections examined for this treatment, more species are likely present within the range of the flora, and a thorough review of North American Plagiomnium is recommended. Three species, Plagiomnium carolinianum, P. rostratum, and P. undulatum, have rostrate opercula; the remaining species have conic-apiculate opercula. Plagiomnium includes four species endemic to the flora area, P. carolinianum, P. ciliare, P. floridanum, and P. venustum, and one apparently introduced species, P. undulatum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 28, p. 231. | FNA vol. 28, p. 229. | ||||||||||||||||||||||||||||||||||||||||
Parent taxa | Mniaceae > Plagiomnium | Mniaceae | ||||||||||||||||||||||||||||||||||||||||
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Synonyms | Mnium cuspidatum | |||||||||||||||||||||||||||||||||||||||||
Name authority | (Hedwig) T. J. Koponen: Ann. Bot. Fenn. 5: 146. (1968) | T. J. Koponen: Ann. Bot. Fenn. 5: 145, figs. 14, 15, 20, 31, 32, 35, 36, 41, 43, 47, 60, 69, 78, 81, 98, 100. (1968) | ||||||||||||||||||||||||||||||||||||||||
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