Plagiomnium venustum |
Plagiomnium undulatum |
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magnificent leafy moss, magnificent moss, plagiomnium moss |
Hart's-tongue thyme-moss |
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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. |
dark green or yellow-green, contorted when dry, transversely undulate when moist, oblong-lingulate, lingulate, narrowly ligulate, or rarely narrowly elliptic, 6–10(–14) mm; base long-decurrent; margins toothed to near base, teeth sharp, of 1 (or 2) cells; apex obtuse or rounded, occasionally acute, usually cuspidate, cusp toothed; costa excurrent; medial laminal cells elongate or short-elongate, (12–)15–30(–40) µm, slightly smaller near margins, occasionally in longitudinal rows, rarely in diagonal rows, collenchymatous, walls pitted or not; marginal cells linear, in (2–)3–4 rows. |
Seta | 1–4(–6), yellow, reddish at base, 3–4 cm. |
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Sexual condition | synoicous. |
dioicous. |
Capsule | horizontal to pendent, oblong, 3–4.5 mm, neck distinct, brown, often wrinkled; operculum conic-apiculate. |
pendent, oblong-cylindric, 2.5–3 mm, neck not distinct; operculum rostrate. |
Spores | 34–40 µm. |
30–35 µm]. |
Erect | stems 2–4(–6) cm, not dendroid; sterile stems absent. |
stems 1–10 cm, ± dendroid; sterile stems to 10(–15) cm. |
Specialized | asexual reproduction by stolonlike stems. |
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[seta 1–4, yellow-green, dark red to blackish with age, 2–4 cm. | ||
Plagiomnium venustum |
Plagiomnium undulatum |
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Phenology | Capsules mature late spring–early summer. | Capsules reportedly mature late spring–early summer. |
Habitat | Humus, soil, sand, logs, stumps, tree bases, rock, concrete, well-drained sites, forests | Shaded soil in urban settings |
Elevation | low to moderate elevations | low elevations |
Distribution |
AK; CA; ID; MT; OR; WA; BC
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BC; Europe [Introduced in North America] |
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.) |
Plagiomnium undulatum, likely an introduction from Europe, recently has been found in Vancouver and Victoria, British Columbia (S. Joya and T. T. McIntosh 2012), where it is well established at a few sites in shaded habitats over soil, especially along roadsides. The species probably has been overlooked because of superficial similarities to P. insigne, a fairly common urban moss in similar habitats; it may be present in other west coast cities. Sporophytes are not known from the flora area (descriptions of the sporophytes are from A. J. E. Smith 2004). The plants often produce subterranean and leafless stolonlike stems. For differences from the similar 1. P. carolinianum, see the discussion of that species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 28, p. 235. | FNA vol. 28, p. 235. |
Parent taxa | Mniaceae > Plagiomnium | Mniaceae > Plagiomnium |
Sibling taxa | ||
Synonyms | Mnium venustum | Mnium undulatum |
Name authority | (Mitten) T. J. Koponen: Ann. Bot. Fenn. 5: 146. (1968) | (Hedwig) T. J. Koponen: Ann. Bot. Fenn. 5: 146. (1968) |
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