Stems rather slender, rarely branched, 1 to 2 feet high. Leaves thin, slightly pubescent on the veins beneath, ovate to lanceolate, 2 to 6 inches long, one-half to 2 inches wide, long pointed at the apex, the middle leaves in whorls of four, the upper and lower leaves smaller and usually opposite. Flowers numerous in one to four terminal umbels on slender stalks; corolla pink or nearly white, its lobes lanceolate-oblong; column short, hoods white, obtuse at the apex, twice as long as the anthers and short incurved horns. Fruiting follicles 3 to 5 inches long, erect on ascending pedicels.
Memoir 15 N. Y. State Museum
Four-Leaved Milkweed - Asclepias quadrifolia
In woods and thickets, Maine to Minnesota, south to Alabama and Arkansas.
The Polk or Tall Milkweed (Asclepias exaltata (Linnaeus) Muhlenberg) is 3 to 6 feet tall, with thin, oval, ovate or oblong leaves, long pointed at each end. Flowers greenish purple, drooping and arranged in few or several umbels toward the top of the plant. Frequent in woods and thickets.
The White Milkweed (Asclepias variegata Linnaeus) occurs only from southern New York southward. The leaves are opposite, ovate, obovate or oblong, thick in texture and sometimes the middle ones verticil-late in fours. Flowers white or the segments purplish near the base.
The Whorled Milkweed (Asclepias verticillata Linnaeus) is very slender and leafy, the leaves linear and verticillate in threes to sixes. Flowers greenish white. It is found in dry or sandy fields in southern New York, and rarely in other portions of the State.