DICOTYLEDONOUS PLANTS 129 



ASCLEPIADA'CE-32. MILKWEED FAMILY 



Herbs with, a milky juice and a tough inner bark having a 

 fiber like flax. Leaves opposite, entire. Flowers peculiar in 

 shape, in umbels. Sepals and petals each 5, reflexed. Anthers 

 forming a crown united to the solid stigma, and with peculiar 

 hood-like appendages surrounding it. The anther cells are 

 orange in color, and are concealed in the crown, and have 

 the outline of a pair of scales. Fruit a pod, opening at one 

 side. Seeds arranged symmetrically on a thick axis, each 

 provided with a tuft of silky down. 



I. ASCLE'PIAS, Silkweed, Milkweed 



The five hoods of the stamens are each provided with a 

 protruding horn. 



a. A. specio'sa Torr. Covered with white down. Stems stout, 

 erect, with large, thick, oblong leaves, opposite or whorled. Umbels 

 on peduncles shorter than the leaves, many-flowered. Flowers large, 

 purple ; the hoods nearly half an inch long, spreading, with a horn- 

 like prolongation from the summit ; besides the short, inflexed true horn. 

 Follicles rough with soft spinous processes. California to Washington. 

 This is inclined to become a troublesome weed. 



b. A. Mexica'na Cav. Stems rather slender, 3-6 ft. high. Leaves 

 in whorls of 3-6, linear, sessile, smooth, 3-6 in. long. Umbels 

 clustered to form a corymb, densely flowered on peduncles longer 

 than the petioles. Flowers rather small, greenish white or tinged 

 witli purple. Hoods broadly ovate, shorter than the beak-like, incurved 

 horn. Follicles slender, tapering to the top. California to Oregon, 

 spreading as if introduced, along highways. 



H. GOMPHOCAR'PUS 



The five hoods are without horns. 



G. cordifo'lius Benth. Smooth, with ascending stems, 2-3 ft. high. 

 Leaves ovate, clasping by a heart-shaped base, opposite or some- 

 times in threes. Umbels 1-4, with the flowers loose, on thread-like 

 pedicels. Corolla dark red-purple. Horns tipped with a point 

 where the open edges come together. Follicles smooth, inclined 



