Asclepias cryptoceras
Humboldt mountains milkweed, Humboldt Mountains Milkweed
(c) Jim Morefield, some rights reserved (CC BY) · licence
Family: Apocynaceae · Type: Herb · Native
Asclepias cryptoceras (Humboldt mountains milkweed) is a native California herb in the Apocynaceae family, recognized by geographic isolation to SNE with distinctive prostrate habit and rounded leaves.
Humboldt mountains milkweed is a California native perennial found in the southern eastern Sierra Nevada region of Mono County in arid plains, canyon bottoms, and slopes with sand, gravel, clay, or shale at elevations of 1,400 to 2,500 meters. Flowering from April to June, this plant produces green-yellow flowers with pink-tan hoods in terminal clusters. Growing with prostrate to decumbent stems that are mostly hairless, it reaches a low-spreading form across the ground. Its opposite leaves have cordate or ovate blades that are approximately round, sometimes with a base that rarely clasps the stem. The fruit develops erect on upright pedicels, with seeds 6 to 8 millimeters long.
Identification and appearance
Key characters: 3 sympatric species; geographic isolation to SNE with distinctive prostrate habit and rounded leaves
Habitat and range
Habitat: Sand, gravel, clay, or shale of slopes, canyon bottoms, washes, arid plains
Elevation: 1400-2500 m
California counties: Mono, Inyo
Outside California: to Washington, Wyoming, Colorado, Arizona
Bloom period
Asclepias cryptoceras blooms Apr-Jun.
How to tell it apart
vs Gomphocarpus: Asclepias has hoods that touch or nearly touch at their edges; Gomphocarpus has gaps between hood edges.; vs Erigeron: Asclepias has rounded umbel clusters with large individual flowers; Erigeron has daisy-like flowers with many thin ray petals.; vs Lantana: Asclepias has reflexed petals with a raised hood crown; Lantana has flat-faced tubular flowers in dense rounded heads.; vs Apocynum: Asclepias has large showy flowers in dome-shaped clusters; Apocynum has tiny bell-shaped flowers in branched sprays.; vs Baccharis: Asclepias has milky sap and large distinctive flowers; Baccharis has clear sap and tiny fuzzy composite flowers.
Frequently asked questions
Is Asclepias cryptoceras native to California?
Yes. Asclepias cryptoceras is native to California (recorded as native).
When does Asclepias cryptoceras bloom?
Asclepias cryptoceras blooms Apr-Jun.
Where in California does Asclepias cryptoceras grow?
Asclepias cryptoceras occurs in Mono, Inyo, at elevations of 1400-2500 m.
What plant family does Asclepias cryptoceras belong to?
Asclepias cryptoceras is in the Apocynaceae family, genus Asclepias.
What habitat does Asclepias cryptoceras grow in?
Asclepias cryptoceras grows in Sand, gravel, clay, or shale of slopes, canyon bottoms, washes, arid plains.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.