Selaginella hansenii
Selaginella watsonii
Hansen's spike-moss
alpine spike-moss, Watson's selaginella, Watson's spike-moss
not readily fragmenting, prostrate, upperside and underside structurally different, irregularly forked, branches determinate, tips upturned.
radially symmetric, decumbent to long-creeping, not readily fragmenting, irregularly forked, without budlike arrested branches, tips straight;
main stem conspicuously determinate, lateral branches conspicuously or inconspicuously determinate, strongly ascending, 1–3-forked.
with underside leaves slightly longer and narrower than upperside leaves, otherwise monomorphic, not clearly ranked, tightly appressed, ascending, green or green with red spots, or reddish, linear-lanceolate (underside) to linear-triangular (upperside), (2–)3–4.5 × 0.5–0.6 mm;
abaxial ridges present;
base abruptly adnate, pubescent (sometimes glabrous);
margins ciliate, cilia white to white opaque, strongly appressed and ascending, 0.03–0.1 mm;
apex with bristle white to white-opaque, 0.5–1.4 mm (those on underside leaves sometimes 1/4–1/2 longer than those on upperside leaves).
monomorphic, in alternate pseudowhorls of 4, tightly or loosely appressed, ascending, green, linear-lanceolate, (2.5–)3–4 × 0.5–0.7 mm;
abaxial ridges prominent;
base cuneate, decurrent, glabrous or sometimes pubescent;
margins entire or short-ciliate, cilia transparent, scattered, spreading, 0.05–0.1 mm;
apex strongly keeled, obtuse, abruptly bristled;
bristle whitish to transparent, smooth, 0.25–0.5 mm.
solitary, 5–7 mm;
sporophylls ovate-deltate to ovate-triangular, abaxial ridges not prominent, base glabrous, margins short-ciliate, apex bristled.
solitary, 0.5–3(–3.5) cm;
sporophylls lanceolate to ovate-lanceolate, abaxial ridges well defined, base glabrous, margins entire, rarely dentate, apex strongly keeled to truncate in profile, short-bristled.
borne on upperside of stems, throughout stem length, 0.25–0.45 mm diam.
borne on upperside of stems, throughout stem length, 0.35–0.55 mm diam.
Selaginella hansenii
Selaginella watsonii
Leaf dimorphism in Selaginella hansenii is only slightly and inconsistently expressed; the upperside leaves tend to be more lanceolate, short, and slightly thick, whereas the underside leaves tend to be more linear, longer, and thinner, but in some specimens the leaves are monomorphic. Red leaves are rare within Selaginella subg. Tetragonostachys, otherwise found in the flora only occasionally in S. rupestris. Such leaves are more common in S. steyermarkii Alston from southern Mexico and Guatemala and S. sartorii Hieronymus from Mexico.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
R. M. Tryon (1955) suggested that Selaginella watsonii is a possible ancestor of (or shares a common ancestor with) S. leucobryoides, S. asprella, and S. utahensis (see discussion).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
OR
Flora NW
PNW Herbaria
