Bryum argenteum
Bryum calobryoides
silver bryum, silver-moss, silvergreen bryum moss, silvery thread moss
bryum moss
0.2–1 cm, strongly rounded julaceous or sometimes gemmiform.
0.5–1.5(–2) cm, strongly rounded 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 when moist, ovate to suborbicular, concave, 0.2–1(–1.2) mm;
base green;
margins weakly recurved proximally, plane distally;
apex broadly rounded to acute, cucullate, not hyaline;
costa not reaching apex to rarely percurrent, apiculus typically present in proximal leaves, absent in distal leaves, of more than 2 cells, sometimes hyaline;
proximal laminal cells predominantly quadrate, 12–18 µm wide, 1–2:1;
distal cells irregularly rhomboidal, (25–)30–75 × (8–)12–25 µm, 1–4:1, walls thin or somewhat thickened, not distinctly incrassate.
brown to red-brown, 1–2 cm.
red to red-brown, ovate, 2–3 mm;
hypophysis differentiated, somewhat thickened.
8–15 µm.
asexual reproduction by leaf axil bulbils, leafy, small.
asexual reproduction absent.
unknown.
Bryum argenteum
Bryum calobryoides
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.)
Bryum calobryoides is easily distinguished by the small strongly julaceous stems, strongly concave leaves, and distal leaves broadly rounded and cucullate. An undescribed species from Colorado occurs in similar habitats but has a short-excurrent costa, acute leaf apices, and unusual, small, irregularly pyriform rhizoidal tubers with bulging cell walls. Collections previously identified as B. gerwigii (Müller Hal.) Limpricht from Alberta are B. calobryoides. Bryum gerwigii is a local waterfall form of Gemmabryum gemmiparum from central Europe.
(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
