418 THE KINDS OF PLANTS 



very short filaments, and mostly monadelphous; the anthers press 

 against the fleshy 5-angled stigma, and the pollen coheres in waxy or 

 granular masses, 1 or 2 to each anther-sac: fruit of 1 or 2 follicles: 

 seeds bearing long silk (Fig. 303). About 2,000 species and 200 genera. 



ASCLfiPIAS. MILKWEED. SILKWEED. 



Erect perennial herbs, with mostly opposite, thick simple leaves and 

 flowers in simple umbels: calyx and corolla each with 5 lobes, bent down- 

 ward, leaving the crown of 5 hood-like appendages, each bearing a horn, 

 conspicuously surrounding the stamens; filaments generally united, and 

 the anthers adherent to the fleshy stigma; anther 2-celled and each cell con- 

 taining a firm, waxy, elongated mass of pollen; adjacent pairs of the pollen- 

 masses are connected and suspended from one of 5 glands resembling a pair 

 of saddle-bags. The flower is peculiarly adapted to insect-pollination, the 

 pollen-masses being carried on the feet of insects. 



A. tuberdsa, Linn. Butterfly weed. Pleurisy root. About 2 ft., with most 

 conspicuous erect clusters of brilliant orange flowers: leaves irregularly scat- 

 tered on stems, or alternate, linear or lance-oblong, hairy, sessile: pods 

 nearly erect, finely pubescent. Dry fields and hillsides. Summer. 



A. incarnata, Linn. Swamp milkweed. Fig. 271. A handsome milk- 

 weed of wet grounds: stems leafy, 2-5 ft.: leaves lanceolate or lance-oblong, 

 acuminate, rather smooth, opposite: flowers rose-colored to white, sweet- 

 scented, in somewhat paniculate umbels: follicles erect, smooth. 



A. syriaca, Linn. (A. Corniiti, Decne.). Common milkweed. Fig. 303. 

 Stems 3-4 ft. high, stout, very milky, usually simple, leafy: leaves large, 

 oblong, downy beneath, stiff, 4-8 in. long, opposite, short -petioled : flowers 

 ^2 in- long, greenish-lavender to lavender, with strong, sweet, but unpleasant 

 odor: pods rough or warty. 



A. purpurascens, Linn. Purple milkweed. Stems erect, 1-3 ft., leafy, 

 simple or branching: leaves oblong or ovate-oblong to elliptical, pointed, 

 short-petioled, 3-6 in. long: flowers large (^ in.), dull purple: pods smooth. 



A. variegata, Linn. Stems simple, smooth, leafy: leaves oval to lance- 

 oval, opposite or whorled, petioled, pale beneath, umbels on downy pedun- 

 cles: corolla white, hoods roundish, sometimes purplish. Dry woods. 



A. quadrifolia, Jacq. Stem 1-2 ft., nearly smooth, and leafy below: 

 1 or 2 whorls of 4-ovate, taper-pointed, petioled leaves near middle and 

 above or below a pair of smaller ones: umbels few, loose-flowered; flowers 

 small, crown white; corolla white, tinged with pink. Slender. 



XLIII. APOCYNACE^. DOGBANE FAMILY. 



Herbs and woody plants, some of the commoner ones resembling 

 milkweeds, in having milky, acrid juice, and seeds crested with silky 

 hairs, but filaments distinct, pollen granular, and corolla twisted 

 (rather than volvate) in the bud: hairs: leaves chiefly opposite, entire, 



