ASCLEPIADACEAE

MILKWEED FAMILY

Carol A. Hoffman

Annual, perennial herb, shrub, vine; sap milky
Leaves simple, generally opposite or whorled; stipules 0 or small
Inflorescence: cyme, terminal or axillary, umbel- or raceme-like, or flower solitary
Flower bisexual, radial; sepals 5, generally reflexed; petals 5, generally reflexed or spreading; stamens 5, fused to form filament column and anther head, generally with 5 elaborate appendages on outside of filament column, pollen removed in pairs of massive sacs; ovaries 2, superior, free, style tips generally fused into massive pistil head surrounded by anther head
Fruit: follicle (1 ovary generally aborts)
Seeds many, ± flat, with tuft of silky hairs
Genera in family: 50–250 genera, 2000–3000 species: especially tropical, subtropical South America, s Africa; ornamental (Asclepias, Hoya, Stapelia). Cardiac glycosides produced by some; used as arrow poisons, in medicine to control heart contraction, and by some insects for defense
Recent taxonomic note: Recently treated to be included within Apocynaceae

ASCLEPIAS

MILKWEED

Annual, perennial herb, shrub
Stem prostrate to erect
Leaves alternate, opposite, or whorled; blade narrowly linear to ovate or cordate
Inflorescence: umbel-like, generally terminal and in (especially upper) axils
Flower: ring of tissue at base of corolla 0; filament-column appendages (hoods) free, sometimes elevated above corolla base, each often with an elongate projection (horn) attached to inside, solid, margins curved in and meeting or nearly meeting on side adjacent to column but not fused; top of pistil head flat or conic
Fruit generally erect (pedicel generally pendent), narrowly ovoid, smooth or with tubercles
Species in genus: 100 species: Am
Etymology: (Asklepios, ancient Greek physician)
Reference: [Woodson 1954 Ann Missouri Bot Gard 41:1–211]

Native

A. californica Greene

CALIFORNIA or ROUND-HOODED MILKWEED

Perennial, densely hairy
Stem decumbent to ± ascending
Leaves opposite, persistent; petiole 0–short; blade ovate
Flower: corolla reflexed, purplish; hoods elevated above corolla base or not, < anther head, dark purple; horns 0–minute
Ecology: Flats, grassy or brushy hillsides
Elevation: 200–2100 m.
Bioregional distribution: c&s Sierra Nevada Foothills, Central Western California, Southwestern California, Desert
Distribution outside California: n Baja California
Flowering time: Apr–Jul
Plants from c&s SNF, CW with hoods elevated above corolla base have been called subsp. greenei Woodson
Horticultural information: TRY.