278 MILKWEED FAMILY. 



A. verticillata, WHORLED M. Dry ground, l-2 high, smoothish ; 

 stems very leafy throughout ; leaves very narrow linear or thread-shaped, in 

 whorls of 3 - 6 ; flowers greenish-white. 



2. ACERATES, GKEEN MILKWEED. (Name from the, Greek, means 

 ivithout a horn, \. e. none to the hood-like appendages, in which it differs from 

 Asclepias.) Flowers green or greenish, in summer. 2/ 



1. Flowers in compact lateral umbels: corolla with oblong re flexed divisions: 

 the hoods erect : ]X)ds slender, sometimes downy, but with the surface even. 



A. viridiflora. Dry sandy or gravelly soil : soft-downy or smoothish, 

 l-2 high; leaves varying from oval to linear, mostly opposite; globular 

 umbels nearly sessile ; flowers short-pedicelled, nearly ' long when open ; 

 hoods not elevated above the base of the corolla. 



A. longifolia. Low barrens W. & S. : rather hairy or roughish, l-3 

 high, with very numerous mostly alternate linear leaves, flowers smaller and on 

 slender pedicels, the umbel peduncled, hoods elevated on a short ring of fila- 

 ments above the base of the corolla. 



2. Flowers in loose terminal and solitary or corymbed nmbels : divisions of the 

 corolla bare'y spreading, but the large hoods spreading and slipper -shaped : 

 pods thick, often with some soft tubercle-like projections. 



A. panic ulata. Dry prairies and barrens from 111. S. W. : smoothish, 

 1 high; leaves alternate, oblong or lance-oblong; flowers 1' broad, green, the 

 hoods purplish. 



3. ENSLENIA. (Named for A. Enslen, an Austrian traveller.) ^ 



E. albida. River-banks from Ohio S. & W. : climbing, 8 -12 ; smooth, 

 with opposite hcjwt-ovate long-petioled leaves, and small whitish flowers in 

 raceme-like clusters on axillary peduncles, all late summer. 



4. VINCETOXICUM. (Name is equivalent to Poison Periwinkle.} 2/ 

 V. nigrum, from Eu. : a low-twining smooth weed, escaping from gardens 



E. ; leaves ovate and lance-ovate ; flowers small, brown-purple, rather few in 

 axillary umbels, in summer. 



5. GONOLOBUS. (Name in Greek means angled pod.} Ours are twin- 

 ing herbs, along river-banks, chiefly S., with opposite heart-shaped petioled 

 leaves, and corymbs or umbels of dark or dull-colored small flowers, on pedun- 

 cles, between the petioles, in summer. 2/ 



G. Isevis. From Virg. to Illinois S. : smooth or only sparingly hairy, the 

 yellowish-green flowers and the longitudinally ribbed pods smooth. 



G. obliquus. From Penn. S. : hairy, somewhat clammy ; flowers mi- 

 nutely downy outside, long and narrow in the bud, dull crimson-purple within, 

 the strap-shaped or lanceolate divisions --' long ; pods ribless, warty. 



G. hirsutus. From Virginia S. : differs from the last in its short-ovate 

 flower-buds, the oval or oblong divisions of corolla only about ' long. 



6. HOYA, WAX-PLANT. (Named for T. Hoy, an English florist.) 



H. carndsa, a well-known house-plant from India ; with rooting stems, 

 thick and fleshy oval leaves, umbels of numerous flesh-colored or almost white 

 flowers, the upper surface of corolla clothed with minute papilla. 



7. STEPHANOTIS. (Name from Greek for crown and ear, referring to 

 the appendages of the stamens.) 



S. floriblinda, from Madagascar : a fine hot-house twiner, very smooth, 

 with opposite oval or oblong thickish leaves, and lateral umbels of very showy 

 fragrant (lowers, the pure white corolla l' in diameter, the tube 1' long. 



