APOCYNACEAE

DOGBANE FAMILY

Lauramay T. Dempster

Perennial (sometimes annual, shrub, vine, tree); sap milky
Leaves simple, entire, opposite, alternate, or subwhorled; stipules 0 or small
Inflorescence: cyme; flowers 1–many, axillary or terminal
Flower bisexual, radial; perianth parts overlapping, at least in bud; sepals 5, fused at base, persistent; petals 5, fused in ± basal half; stamens 5, attached to corolla tube or throat, alternate lobes; ovaries 2, ± superior, generally free, styles and stigmas fused
Fruit: generally 2 follicles
Seeds many, often with tuft of silky hairs
Genera in family: ± 150–200 genera, 1000–2000 species: especially tropical; many ornamental (Nerium, oleander; Plumeria , frangipani); some alkaloids highly toxic, some used in medicine
Recent taxonomic note: Recently treated to include Asclepiadaceae
Reference: [Rosatti 1989 J Arnold Arbor 70:307–401]

APOCYNUM

DOGBANE, INDIAN HEMP

Stem ascending to erect
Leaves opposite
Inflorescence: flowers several–many
Flower small; corolla cylindric to bell-shaped, 5-lobed, with 5 triangular appendages alternate stamens; stamens attached at base of tube, filaments short, wide, anthers forming adherent cone around stigma, each partly sterile, sharply sagittate; nectaries 5, free, around and < ovaries; style ± 0, stigma massive, ovoid, obscurely 2-lobed
Fruit slender, cylindric, pointed
Seed with tuft of long hairs
Species in genus: ± 7 species: North America
Etymology: (Greek: away from, dog, from ancient use as dog poison)
. The 2 CA species hybridize extensively; many hybrid forms have been named.

Native

A. androsaemifolium L.

BITTER DOGBANE

Stem diffusely branched
Leaf: petiole << blade; blade 4–6 cm, base generally round or cordate, tip round or obtuse to ± acute
Flower: corolla 4–8 mm, ± bell-shaped
Fruit 7–11 cm, pendent to erect
Ecology: Open slopes, rocky places, with conifers, chaparral
Elevation: 200–2500 m.
Bioregional distribution: Klamath Ranges, High North Coast Ranges, Inner North Coast Ranges, High Cascade Range, High Sierra Nevada, San Francisco Bay Area, Inner South Coast Ranges, San Bernardino Mountains, San Jacinto Mountains, Modoc Plateau, White and Inyo Mountains
Distribution outside California: to e N.America, Canada
Flowering time: Jun–Aug
Synonyms: var. glabrum Macoun; A. medium Greene var. floribundum (Greene) Woodson; A. pumilum (A. Gray) Greene
Horticultural information: DRN: 1, 4, 5, 6, 15, 17 &SHD: 2, 3, 16 &IRR: 7, 14, 18, 20, 21; STBL, INV.