Apocynum androsaemifolium L.

Spreading Dogbane


CC = 5
CW = 5
MOC = 27

© SRTurner

Family - Apocynaceae

Habit - Perennial herb, sometimes woody at base, with milky sap.

Stems - Ascending to erect, to 1.5 m, branched, glabrous, often glaucous, terete.

Leaves - Opposite, occasionally some subopposite or alternate, short-petiolate or sessile, the lower leaves typically drooping. Petioles to 5 mm. Leaf blades ovate to elliptic, to 9 cm, entire, the upper surface glabrous, the lower surface usually sparsely pubescent, rounded to angled and often mucronate at the tip, often somewhat asymmetrical at the rounded base.

Apocynum_androsaemifolium_pressed_leaves.jpg Pressed leaves.

© DETenaglia

Apocynum_androsaemifolium_leaves.jpg Fresh leaves.

© DETenaglia

Inflorescences - Terminal or axillary, branched loose clusters of few to many flowers. Flowers sweetly fragrant. Peduncles and pedicels glabrous. Peduncles to 4 cm long. Pedicels to 4 mm long in flower.

Apocynum_androsaemifolium_inflorescence2.jpg Inflorescences.

© SRTurner

Flowers - Calyces glabrous, the lobes 1.5-2.5 mm long, ovate-triangular. Corollas 5-lobed, bell-shaped, 4-7 mm long, whitish to pink, with pink stripes on the inner surface, the tube 3-4 mm long, usually more than twice as long as the calyx, 4-5 mm wide at the tip, the lobes 2-3 mm long, spreading or recurved. Stamens 5, curving inward to form a cone over the stigma, the filaments 0.8-1.1 mm long, hairy. Anthers 2.5-3.2 mm long. Nectar glands 5, green, alternating with stamens. Pistils 2, green, glabrous. Styles 0.7-1.0 mm long, the ovoid stigma about 1 mm long.

Apocynum_androsaemifolium_flowers3.jpg Flowers.

© SRTurner

Apocynum_androsaemifolium_flowers.jpg Flowers.

© SRTurner

Apocynum_androsaemifolium_flowers2.jpg Corollas.

© DETenaglia

Fruits - Follicles to 9 cm, pendent, slender, straight. Seeds numerous, 2-3 mm long, narrowly cylindrical, somewhat tapered toward the base, with a tuft of hairs at the truncate tip.

Apocynum_androsaemifolium_fruits.jpg Fruits.

© SRTurner

Flowering - May - July.

Habitat - Dry open rocky woods, thickets, roadsides.

Origin - Native to the U.S.

Other info. - This species is scattered and not very common in Missouri. It is far more common in the upper Midwest and in the western half of the U.S. When blooming it is easy to identify by its distinctive flowers, which have recurved lobes and pink internal stripes. The species has been subdivided, and according to this classification Missouri plants would be referable to var. androsaemifolium.

This species has the typical white milky sap of the Apocynaceae and can be toxic if eaten. Fruit set is usually low despite the great popularity of the flowers with flying insects. Traditionally the plant was used as an emetic and a diuretic. The strong fibers of the plant can be made into rope.

Photographs taken at Pictured Rocks National Seashore, MI., 7-12-02 (DETenaglia); also in Larimer County, CO, 7-10-2014, 7-30-2017, 6-23-2018, and 7-9-2019, and near Liberty Lake, Spokane County, WA, 7-24-2021 (SRTurner).