Asclepias syriaca L. - Milkweed

Taxonomic position.

Family Asclepiadaceae R. Br., genus Asclepias L.

Morphology and biology.

Perennial plant. Stems are herbaceous, simple, thick, sparsely covered with short, curly hairs. Upper internodes are whitish because of dense pubescence, while a strip of denser down runs along the whole stem. Set on short stalks, leaves are oblong-elliptical, 13-20 cm long and 7-9.5 cm wide, rounded or slightly cordate at the base, with an acerated tip and a thick midrib, whitish from below because of dense, tomentose pubescence and covered from above with scattered hairs. Ultimate umbels are polyanthous, set on peduncles 4-8 cm long. Peduncles are downy and located between leafstalks in the upper part of the plant. Pubescent pedicels are 2.5 times longer than the flowers. Flowers are large and red; calyx lobes are reclinate, ovate, 3-4 mm long, cuspidated, and downy. Corolla is incised almost to the base; its lobes are oval, 6-7 mm long, a little narrowed toward the tip, obtuse, covered on the outside with curly white hairs. Staminal crown consists of five mitriform lobes with two denticles at the corners on the inside and a hornlike, flat appendage in the inner cavity of the cap. Anthers are broadened at the base with a very wide connective and a small, ovoid, scarious appendage at the top. Stigma is pentagonal, depressed, with slits to accommodate pollen brought by insects. Follicles are thick, elliptical, 6-10 cm long and 1.5-2.5 cm wide, whitish from the dense, short and soft pubescence, additionally covered with tiny bristly thorns. Seeds are ovoid, 0.9-1 cm long, flatly depressed, brown, with a broad, wrinkly edge and elongated, dark protuberances on both sides. Blossoms in June; bears fruit in September. Entomophilous. Zoochore.


General distribution: its natural area is North America. Within the former USSR: occurs as a naturalized introduced plant in forest-steppe areas of the Ukraine and the Caucasus.


Usually in open places along roads, along field edges, in forest shelterbelts, and as weeds.

Utilization and economic value.

Seeds contain 19-21% semidrying oil used for making liquid soap and producing dry fats through hydrogenation. Cake remaining after oil extraction contains up to 47% raw protein and is used for feed. It is an excellent nectariferous plant.

Reference citations:

Shishkin, B.K. & E.G. Bobrov. 1952. Flora USSR. V. XVIII. Moscow-Leningrad: Publishing House of Acad. Science. 802 p. (In Russian)
Cherepanov S.K. 1995. Plantae Vasculares Rossicae et Civitatum Collimitanearum (in limics USSR olim)[List of Vascular Plants of Russia]. St. Petersburg: Mir I Semia. 990 pp. (In Russian)
Grossgheim, A.A. 1967. Flora of Caucasia. V. 7. Leningrad: Nauka. 220 p. (In Russian)

© Smekalova, T.N.

Copyright on this picture belongs to Robert Flogaus-Faust: Bild (c) Robert Flogaus-Faust ( ).

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