General: Hartweg's Climbing Milkweed (Funastrum heterophyllum) is a vine with narrow, arrowhead shaped leaves; purple milkweed flowers; and elongate seedpods. The flower petals (corolla lobes) open and spread, the tips do not meet, and the open flower does not look like a closed flower bud. Fruits usually produced signally rather than in pairs, 7-11 cm long. On the flower, the ring at tissue the base of the petals free from filament column appendages.

Hartweg's Twinevine is an uncommon component of desert and upland vegetation communities. It can be found on flats, in and along washes, and on bajadas into the lower mountains in the Lower Sonoran (Creosote-Bursage Flats) and Upper Sonoran (Mojave Desert Scrub and Pinyon-Juniper Woodland) life zones. The species also occurs in disturbed areas, such as along roads.

Family: Milkweed (Asclepiadaceae)

Other Names: Hartweg's Twinevine, Funastrum cynanchoides var. hartwegii, Sarcostemma cynanchoides ssp. hartwegii, Sarcostemma cynanchoides var. hartwegii.

Plant Form: Vine

Height: Not tall, but grows on other plants

Stems: Narrow, vine.

Leaves: Opposite, elongate, arrowhead shaped, generally without hairs.

Flowers: Purple

Seeds: Produces an elongate seedpod. Individual seeds with long hairs attached.

Habitat: Dry soils on flats, in and along washes, and on bajadas into the lower mountains.

Elevation: To about 4,000 feet

Distribution: California to Texas.

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