Apocynum androsaemifolium L.

Apocynum androsaemifolium plant

Family - Apocynaceae

Stems - To 2m tall, erect, branching, glabrous, often purplish, terete, with milky sap, herbaceous.

Leaves - Opposite, decussate or not, at least the lower leaves typically drooping, petiolate. Petioles to 6mm long, glabrous to pubescent or not. Blades ovate, acute, mucronate, glabrous adaxially, pubescent to glabrous abaxially, entire, rounded at base, lighter colored abaxially, deep green above, to +10cm long, +5cm broad.

Apocynum androsaemifolium leavesPressed leaves.

Apocynum androsaemifolium leavesFresh leaves.

Inflorescence - Terminal pedunculate cymes. Peduncles and pedicels glabrous. Peduncles to 4cm long. Pedicels to 4mm long in flower.

Apocynum androsaemifolium inflorescence

Flowers - Corolla whitish to pink or with pink stripes, 5-7mm long, 5-lobed. Lobes to +3mm long, spreading to recurved, rounded to acute at apex. Stamens 5, erect, connivent around the pistil. Filaments short, thick, with floccose hairs internally at the midpoint, 1.5mm long. Anther connective sagittate, expanded, +/-2.5mm long, golden-yellow. Stamens alternating with green nectaries at base. Anthers with white nectaries internally surrounding the stigmas. Pistils 2, green, glabrous, 1.5-2mm long. Styles united and cylindrical with small a small ring below the stigmas. Placentation axile, seeds (ovules) many. Ovary partially inferior. Calyx tube 1.3mm long, glabrous, 5-lobed. Lobes whitish, acute, triangular, to 2mm long, glabrous.

Apocynum androsaemifolium flowers

Apocynum androsaemifolium flowers

Flowering - May - July.

Habitat - Dry open rocky woods, thickets, roadsides.

Origin - Native to U.S.

Other info. - This species can be found scattered throughout much of Missouri but is absent from a few locations such as the extreme NW and SW corners of the state. The plant is easy to ID in the field because of its distinctive flowers, which have recurved lobes. This species has the typical white milky sap of the Apocynaceae and can be toxic if eaten. 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.


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