Plagiomnium cuspidatum |
Plagiomnium venustum |
|
---|---|---|
baby tooth moss, tooth plagiomnium moss, woods leafy moss, woodsy mnium |
magnificent leafy moss, magnificent moss, plagiomnium moss |
|
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, crisped and contorted, distally often densely twisted around stem when dry, flat when moist, obovate or elliptic, 3–5(–7) mm; base decurrent or not; margins toothed to 2/3 leaf length or sometimes just past mid leaf or to base, teeth sharp, of 1–2(–3) cells; apex acute, acuminate, or rarely obtuse or rounded, cuspidate, cusp toothed; costa percurrent, excurrent, or rarely subpercurrent; medial laminal cells short-elongate or ± isodiametric, (17–)25–40(–45) µm, slightly smaller near margins, in longitudinal, rarely diagonal rows, strongly collenchymatous, walls not pitted; marginal cells linear, in (3–)4–5 rows. |
Seta | single, yellow, brown, or sometimes reddish, 2–3 cm. |
1–4(–6), yellow, reddish at base, 3–4 cm. |
Sexual condition | synoicous. |
synoicous. |
Capsule | pendent, ovoid or cylindric, 2–3.5 mm, neck not distinct; operculum conic-apiculate. |
horizontal to pendent, oblong, 3–4.5 mm, neck distinct, brown, often wrinkled; operculum conic-apiculate. |
Spores | 18–31 µm. |
34–40 µm. |
Erect | stems 1–2(–3.5) cm, not dendroid; sterile stems to 7 cm. |
stems 2–4(–6) cm, not dendroid; sterile stems absent. |
Plagiomnium cuspidatum |
Plagiomnium venustum |
|
Phenology | Capsules mature late spring. | Capsules mature late spring–early summer. |
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 | Humus, soil, sand, logs, stumps, tree bases, rock, concrete, well-drained sites, forests |
Elevation | low to moderate elevations | 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
|
AK; CA; ID; MT; OR; WA; BC
|
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.) |
Plagiomnium venustum is the only species of the genus that lacks sterile stems. It is a common western species that forms large, handsome mats or turfs in many northwest coastal forests, especially noticeable on tree bases. Sporophytes are common. Another distinctive feature of P. venustum is the presence of dark and mammillose stomatal guard cells in the necks of the capsules. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 28, p. 231. | FNA vol. 28, p. 235. |
Parent taxa | Mniaceae > Plagiomnium | Mniaceae > Plagiomnium |
Sibling taxa | ||
Synonyms | Mnium cuspidatum | Mnium venustum |
Name authority | (Hedwig) T. J. Koponen: Ann. Bot. Fenn. 5: 146. (1968) | (Mitten) T. J. Koponen: Ann. Bot. Fenn. 5: 146. (1968) |
Web links |
|