Selaginella watsonii

L. Underwood

Bull. Torrey Bot. Club 25: 127. 1898.

Common names: Alpine spike-moss Watson's spike-moss
Endemic
Treatment appears in FNA Volume 2.

Plants on rock or terrestrial, forming long or compact cushionlike mats. Stems 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. Rhizophores borne on upperside of stems, throughout stem length, 0.35–0.55 mm diam. 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. Strobili solitary, 0.5–3 (–3.5) cm; sporophylls lanceolate to ovatelanceolate, abaxial ridges well defined, base glabrous, margins entire, rarely dentate, apex strongly keeled to truncate in profile, short-bristled.


Habitat: On exposed or shaded cliffs, rocky slopes, rock crevices, granite boulders, quartzite rock, gravelly or sandy soil, alpine meadows, or swampy grounds
Elevation: 1800–4300 m

Distribution

V2 579-distribution-map.gif

Ariz., Calif., Idaho, Mont., Nev., Oreg., Utah, Wyo.

Discussion

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).

Selected References

None.

Lower Taxa

None.
... more about "Selaginella watsonii"
defined +  and prominent +
Iván A. Valdespino +
L. Underwood +
glabrous +  and pubescent +
decurrent +  and cuneate +
whitish;transparent +
0.025 cm0.25 mm <br />2.5e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
transparent +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.01 cm0.1 mm <br />1.0e-4 m <br />) +
Alpine spike-moss +  and Watson's spike-moss +
Ariz. +, Calif. +, Idaho +, Mont. +, Nev. +, Oreg. +, Utah +  and Wyo. +
1800–4300 m +
On exposed or shaded cliffs, rocky slopes, rock crevices, granite boulders, quartzite rock, gravelly or sandy soil, alpine meadows, or swampy grounds +
monomorphic +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
3mm;4mm +
fertile +  and vegetative +
linear-lanceolate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
short-ciliate +  and entire +
dentate +  and entire +
cushionlike +
globose +, ovoid +  and tetrahedral +
tetrahedral +
Bull. Torrey Bot. Club +
alternating +
0.035 cm0.35 mm <br />3.5e-4 m <br /> (0.055 cm0.55 mm <br />5.5e-4 m <br />) +
adjacently +  and monomorphic +
fertile +  and vegetative +
branched +, not +  and articulate +
dimorphic +, climbing +  and cespitose +
decumbent;long-creeping +
3 cm30 mm <br />0.03 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
quadrangular +
0.5 cm5 mm <br />0.005 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Selaginella watsonii +
Selaginella subg. Tetragonostachys +
species +
straight +
branched +  and not articulate +
erect +  and creeping +
branched +  and not articulate +
erect +  and creeping +
differentiated +
perennial +  and annual +
epiphytic +  and hemiepiphytic +
12 +, 11 +, 10 +, 9 +, 8 +  and 7 +