Asclepias cryptoceras subsp. davisii

(Woodson) Woodson

Ann. Missouri Bot. Gard. 41: 180. 1954.

Common names: Humboldt Mountains or pallid or Davis’s or jewel milkweed
IllustratedEndemic
Basionym: Asclepias davisii Woodson Ann. Missouri Bot. Gard. 26: 261, fig. 1. 1939
Synonyms: A. cryptoceras var. davisii (Woodson) W. H. Baker
Treatment appears in FNA Volume 14.

Leaves: petiole 2–8 mm; blade oval to ovate or obovate or orbiculate, 3–7 × 1.8–4.8 cm, apex rounded to acute, venation eucamptodromous, surfaces gla­brous. Inflorescences 3–8-flowered. Pedicels 16–25 mm. Flowers: calyx lobes 5–6 mm; corolla lobes 8–11 mm; fused anthers dark brown, green at apex, 1.8–2.5 mm; corona segments pinkish purple, 5–6(–7) mm, apices (including recurved tooth) exceeded by or equaling style apices.


Phenology: Flowering Apr–Jul; fruiting May–Jul.
Habitat: Slopes, hills, arroyos, basalt, silicic tuff, limestone, chert, serpentine, gravel, sand and clay soils, juniper woodlands, shrubby grasslands, steppe.
Elevation: 300–1500(–2100) m.

Distribution

Calif., Idaho, Nev., Oreg., Wash.

Discussion

Subspecies davisii just enters Washington in Asotin County and is exceedingly rare in the state, where it is considered to be of conservation concern.

Selected References

None.

Lower Taxa

None.
Mark Fishbein +
(Woodson) Woodson +
Asclepias davisii +
Humboldt Mountains or pallid or Davis’s or jewel milkweed +
Calif. +, Idaho +, Nev. +, Oreg. +  and Wash. +
300–1500(–2100) m. +
Slopes, hills, arroyos, basalt, silicic tuff, limestone, chert, serpentine, gravel, sand and clay soils, juniper woodlands, shrubby grasslands, steppe. +
Flowering Apr–Jul +  and fruiting May–Jul. +
Ann. Missouri Bot. Gard. +
Illustrated +  and Endemic +
A. cryptoceras var. davisii +
Asclepias cryptoceras subsp. davisii +
Asclepias cryptoceras +
subspecies +