Athysanus pusillus

(Hooker) Greene

Bull. Calif. Acad. Sci. 1: 72. 1885.

Illustrated
Basionym: Thysanocarpus pusillus Hooker Icon. Pl. 1: plate 42. 1837
Synonyms: Athysanus pusillus var. glabrior S. Watson Thysanocarpus oblongifolius
Treatment appears in FNA Volume 7. Treatment on page 267. Mentioned on page 268.

Plants sparsely to densely pubescent proximally, sometimes glabrous distally. Stems (0.2–)0.5–3(–5) dm. Basal leaves: petiole 0.1–0.5 cm; blade oblanceolate, obovate, or oblong, 0.3–1.5(–2) cm × (1–)2–6(–8) mm, margins entire or dentate, apex acute to obtuse, surfaces uniformly pubescent, trichomes cruciform and 3-rayed, adaxially sometimes mixed with coarse, simple ones. Cauline leaves 1–6; blade similar and equaling or smaller than basal. Fruiting pedicels slender, (1.5–)2–4(–6) mm. Flowers: sepals 0.5–1 × 0.3–0.7 mm; petals oblong, 1.5–3 × 0.5–1 mm; filaments 0.4–0.6 mm; anthers (0.05–)0.1–0.2(–0.25) mm. Fruits usually orbicular to obovate, rarely broadly oblong, 1-locular, not twisted; valves thin, veins sometimes prominent, usually pubescent, rarely glabrous, trichomes simple, to 0.5 mm, hooked (sometimes restricted to margins, or mixed with smaller, sessile, cruciform or 3-rayed ones); septum absent; ovules 2(–4) per ovary; style 0.05–0.2 mm. Seeds 1, (0.8–)0.9–1.1(–1.2) × (0.5–)0.7–0.9(–1) mm. 2n = 26.


Phenology: Flowering Feb–Jun.
Habitat: Open grassy slopes, grassy glades in woodlands, chaparral, sandy and gravelly flats, flood plains, rock outcrops, cliffs and ledges, on limestone, serpentine, sandstone, granitic and basaltic substrates
Elevation: 0-1800 m

Distribution

V7 357-distribution-map.gif

B.C., Ariz., Calif., Idaho, Mont., Nev., Oreg., Wash., Mexico (Baja California).

Discussion

Records of Athysanus pusillus for Montana appear to be solely from Ravalli County, and for Nevada from Storey and Washoe counties.

Selected References

None.

Lower Taxa

None.
... more about "Athysanus pusillus"
Ihsan A. Al-Shehbaz +
(Hooker) Greene +
Thysanocarpus pusillus +
B.C. +, Ariz. +, Calif. +, Idaho +, Mont. +, Nev. +, Oreg. +, Wash. +  and Mexico (Baja California). +
0-1800 m +
Open grassy slopes, grassy glades in woodlands, chaparral, sandy and gravelly flats, flood plains, rock outcrops, cliffs and ledges, on limestone, serpentine, sandstone, granitic and basaltic substrates +
Flowering Feb–Jun. +
Bull. Calif. Acad. Sci. +
Illustrated +
Athysanus pusillus var. glabrior +  and Thysanocarpus oblongifolius +
Athysanus pusillus +
Athysanus +
species +