Bryum argenteum
Bryum lanatum
silver bryum, silver-moss, silvergreen bryum moss, silvery thread moss
0.2–1 cm, strongly rounded julaceous or sometimes gemmiform.
0.5–1(–1.5) cm, evenly foliate, weakly julaceous.
erect when moist, ovate to ovate-lanceolate, somewhat concave, 0.3–1(–1.2) mm;
base green;
margins rarely recurved proximally or plane distally;
apex broadly rounded to acute, not cucullate, hyaline in distal 1/4–1/2 of leaf or rarely nearly entirely green;
costa not reaching apex, apiculus present, sometimes short or nearly absent, hyaline, irregularly incurved when dry;
proximal laminal cells quadrate or short-rectangular, 12–18 µm wide, 1–2:1;
distal cells short- or elongate-hexagonal, (30–)40–80 × 10–15 µm, (1–)3–5:1, walls thin or somewhat thickened, not distinctly incrassate.
erect-spreading when moist, ovate to ovate-lanceolate, somewhat concave, 0.3–1(–1.5) mm;
base concolorous;
margins recurved proximally, plane distally;
apex acute, not cucullate, hyaline in distal 1/2 of leaf;
costa long-excurrent, awn slender, hyaline, recurved when dry;
proximal laminal cells quadrate or short-rectangular, 10–16 µm wide, 1–2:1;
distal cells elongate-hexagonal, 40–60 × 10–16 µm, 4–5:1, walls somewhat thickened to distinctly incrassate.
brown to red-brown, 1–2 cm.
brown to red-brown, 1–2 cm.
red to red-brown, ovate, 2–3 mm;
hypophysis differentiated, somewhat thickened.
brown to red-brown, ovate, (1–)2–3 mm;
hypophysis differentiated, somewhat thickened and rugose.
8–15 µm.
8–15 µm.
asexual reproduction by leaf axil bulbils, leafy, small.
asexual reproduction absent.
Bryum argenteum
Bryum lanatum
Varieties ca. 30 (3 in the flora).
Bryum argenteum is perhaps the most widespread and distinctive moss in the world, although in many regions it is found primarily in urban or other heavily disturbed sites and is mostly absent from native undisturbed habitats in the tropics. There are about 15 silver-white species described, with species definitions based on a combination of one of three or four different basic gametophyte morphologies combined with subtle differences in the sporophytes. However, much of the gametophyte variability in the complex is also exhibited by B. argenteum itself, thus confusing species-level identifications. This complex is urgently in need of worldwide molecular and morphological studies.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Although typically considered a variety of Bryum argenteum, B. lanatum from western North America and other parts of the world is quite distinctive. However, the type of B. lanatum from Europe may be a form of B. argenteum, in which case a new name will be needed. The species is characteristic of undisturbed native plants communities and is especially common in semiarid parts of the West on dry soil; capsules are rare. Bryum argenteum generally grows in more moist climates in highly disturbed sites, especially where there is excess nitrogen. The distribution of B. lanatum in the eastern part of North America is not well understood because the species has been combined with B. argenteum by bryologists of that region.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Stems loosely julaceous; plants green; leaves hyaline near apex; costal apiculus long. | var. majus |
1. Stems distinctly julaceous or gemmiform to short-julaceous; plants hoary white to silver-green; leaves hyaline in distal 1/4 -1/2; costal apiculus absent, short, or long | → 2 |
2. Stems 0.5-1 cm, julaceous; leaves longer than broad; distal laminal cells elongate, 3-4(-5):1; costal apiculus long. | var. argenteum |
2. Stems shorter than 0.2 cm, sometimes gemmiform; leaves often broader than long; distal laminal cells short, (1-)2-3:1; costal apiculus absent or very short. | var. muticum |
BC
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
CalFlora
Flora NW
KS Wildflowers
MO Plants
