Plagiomnium venustum |
Mniaceae |
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magnificent leafy moss, magnificent moss, plagiomnium moss |
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Habit | Plants small to large, in loose to dense tufts or mats. | |||||||||||||||||||||||||||||||||||||
Stems | green, yellow-green, brown, reddish brown, or black, rarely yellowish brown, erect, arching, inclined, or plagiotropic, usually simple, sometimes branched distally, rarely dendroid; rhizoids brown or reddish brown, of two types, macronemata larger and usually strongly branched, mainly proximal, often matted, mainly restricted to leaf or branch bases distally, rarely along leaf bases, and micronemata, smaller, less branched and paler, present or absent on stems. |
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Leaves | 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. |
green, yellowish green, or reddish, rarely bluish green, usually small and distant proximally, larger and more crowded distally, sometimes forming terminal rosettes, sometimes incurved upwards, usually crisped or contorted, sometimes undulate when dry, spreading, erect-spreading, reflexed, or arcuate-recurved, flat or sometimes keeled, rarely undulate when moist, orbicular, spatulate, lingulate, ligulate, elliptic, ovate, ovate-lanceolate, or obovate; base decurrent or not; margins usually plane, sometimes recurved, green, brown, red, or reddish brown, 1- or 2-stratose, rarely multistratose, rarely with stereid band, entire or toothed distally or to leaf base, teeth single or paired, sharp or blunt, of 1(–4) cells; apex acute, obtuse, acuminate, or rounded, sometimes emarginate or retuse, often apiculate, sometimes cuspidate, cusp often toothed; costa single, excurrent, percurrent, subpercurrent, or ending well before apex, distal abaxial surface smooth or toothed, adaxial surface rarely toothed, teeth of 1(–3) cells, 1 or 2 stereid bands present, rarely absent, (abaxial stereid band U-shaped in Cinclidium); alar cells undifferentiated; medial laminal cells usually short-elongate, sometimes ± isodiametric, hexagonal, sometimes pentagonal, rarely four-sided, usually 2:1 or less (3+:1 in Pseudobryum), sometimes in longitudinal or diagonal rows, smooth (mammillose in Trachycystis), collenchymatous or not, walls pitted or not; marginal cells usually differentiated, linear, rhomboidal, or rectangular, in (1–)2–3(–6) rows. |
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Seta | 1–4(–6), yellow, reddish at base, 3–4 cm. |
single or sometimes double or several, yellow, brown, red, yellowish green, yellowish brown, reddish brown, or orange-yellow, sometimes blackish with age, elongate, straight or flexuose, smooth. |
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Sexual condition | synoicous. |
synoicous or dioicous. |
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Capsule | horizontal to pendent, oblong, 3–4.5 mm, neck distinct, brown, often wrinkled; operculum conic-apiculate. |
horizontal to pendent, yellow, brown, yellowish brown, or yellowish green, elliptic, ovate, subglobose, oblong, or cylindric; stomata cryptoporous (phaneroporous in Cyrtomnium); annulus deciduous; operculum conic or hemispheric, apiculate, mammillate, or rostrate; peristome double, complete; exostome teeth 16, usually lanceolate-acuminate, external surface lamellose; endostome usually equal in size to exostome, basal membrane high, segments often perforate with gaps along keels, cilia nodulose (endostome domed, fused at apex, perforated when mature, with keeled columns distally, alternating with shorter exostome teeth in Cinclidium). |
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Calyptra | cucullate, usually naked. |
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Spores | 34–40 µm. |
spheric, smooth or papillose, brown. |
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Erect | stems 2–4(–6) cm, not dendroid; sterile stems absent. |
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Plagiomnium venustum |
Mniaceae |
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Phenology | Capsules mature late spring–early summer. | |||||||||||||||||||||||||||||||||||||
Habitat | Humus, soil, sand, logs, stumps, tree bases, rock, concrete, well-drained sites, forests | |||||||||||||||||||||||||||||||||||||
Elevation | low to moderate elevations | |||||||||||||||||||||||||||||||||||||
Distribution |
AK; CA; ID; MT; OR; WA; BC
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Nearly worldwide; circumtemperate to circumboreal |
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Discussion | 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.) |
Genera 12, species 92 (8 genera, 37 species in the flora). Mniaceae is a diverse family generally characterized by relatively large plants with broad leaves, and with short-elongate or more or less isodiametric laminal cells most often hexagonal and angular. Leaf margins are usually differentiated by a border of elongate cells and range from smooth to strongly toothed. The family is also characterized by a wide degree of morphological variation as a response to environmental conditions, age, or sexuality. Fertile stems are sometimes strikingly different from sterile stems, and female or synoicous plants are sometimes different from male plants. This makes the identification of weakly developed specimens difficult. Many species in the family are fairly common in temperate and boreal habitats in the Northern Hemisphere and are frequently collected in ecologically based surveys. The following keys stress vegetative traits and are best employed using well-developed, mature plants. Leaf laminal and marginal cell characters were derived by examining cells near mid leaf. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 28, p. 235. | FNA vol. 28, p. 215. | ||||||||||||||||||||||||||||||||||||
Parent taxa | Mniaceae > Plagiomnium | |||||||||||||||||||||||||||||||||||||
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Synonyms | Mnium venustum | |||||||||||||||||||||||||||||||||||||
Name authority | (Mitten) T. J. Koponen: Ann. Bot. Fenn. 5: 146. (1968) | Schwagrichen | ||||||||||||||||||||||||||||||||||||
Web links |