MILKWEED FAMILY 179 



on the grasses. The milky sap is a clue to their identity. 

 Philibertella clausa, an evergreen vine, has conspicuous 

 umbels of white flowers. The unattractive metastelmas 

 grow in masses of slender green stems, with narrow leaves, 

 and with umbels of minute flowers sessile in the leaf- 

 axils. In Seutera the umbels of green or brownish flowers 

 are stalked. 



The name of silkweed is appropriate when the bursting 

 pods set free the seeds, tipped with parachutes of glisten- 

 ing hairs that float them on the breeze. The seedpods 

 open on only one side, and are technically known as 

 follicles. 



This family is remarkable in many ways. The milky 

 latex of some species forms caoutchouc, and that of the 

 cow-plant of Ceylon is used as food. Strange, cactus-like 

 forms are shown by a number of South African species, 

 of which the toad-cactus, or carrion-flower, Stapelia, is an 

 example, and several genera are epiphytes with peculiar 

 foliage. 



ERECT OR PROSTRATE PLANTS (not vines) 



Asclepias tuberosa. Flowers orange or reddish, small, in 

 several umbels forming a somewhat flat-topped terminal 

 inflorescence. Calyx small, 5-lobed, corolla 5-parted, lobes 

 reflexed, stamens 5. Seedpods 3-4 in. long. ^ Stems 1-2 ft. 

 tall. Leaves mostly alternate, oblong, 2-6 in. long. Dry 

 soil. Blooming from midwinter to fall. Fla. to Texas and 

 northward. 



Asclepias huinistrata. Flowers ash-color or pale purple, 

 in stalked globular umbels from axils of upper leaves. Seed- 

 pods 4-6 in. long. Stems 1-2 ft. long, prostrate or ascending. 

 Leaves opposite, broad, pale green, .2-6 in. long. Dry sand. 

 Fla. to N. C. 



Asclepias tomentosa. Flowers greenish, in many sessile 

 umbels in axils of upper leaves. Stems 1-3 ft. tall. Leaves 

 opposite, many, oblong, 1-3 in. long. Sandy soil. Fla. and 

 Ga. 



