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. cannabinum L.

INDIAN HEMP

Stem stout, ± stiffly erect, branched near top
Leaf: petiole << blade; blade 5–8 cm, base tapered to cordate, sometimes clasping stem, tip obtuse to acute
Flower: corolla 2.5–5 mm, cylindric to urn-shaped
Fruit 6–9 cm, ± pendent
Ecology: Moist places near streams, springs, etc., or weed in orchards
Elevation: < 2000 m.
Bioregional distribution: Klamath Ranges, North Coast Ranges, High Cascade Range, High Sierra Nevada, Tehachapi Mountain Area, San Joaquin Valley, San Francisco Bay Area, South Coast Ranges, Transverse Ranges, Peninsular Ranges, Great Basin Floristic Province
Distribution outside California: to British Columbia, e N.America
Flowering time: Jun–Aug
Synonyms: var. glaberrimum A. DC.; A. sibiricum Jacq. var. salignum (Greene) Fernald
Horticultural information: WET: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21; STBL, INV; important traditional source of fiber..