MORNING-GLORY FAMILY 197 



4. A. syriaca L. COMMON MILKWEED. Stem stout, 3-4 ft. high, 

 finely downy. Leaves 4-8 in. long, oblong or nearly so, downy be- 

 neath. Umbels terminal or nearly so. Flowers varying from purple 

 or greenish-purple to whitish, numerous, with a strong, sweet but 

 sickening odor ; hoods with a tooth on each side of the stout horn. 

 Common in rich soil. 



5. A. phytolaccoides Pursh. POKE-LEAVED MILKWEED. Stem 

 rather slender, 3-5 ft. high. Leaves 6-9 in. long, ovate or oval- 

 lanceolate, taper-pointed, short-petioled. Umbels several, mostly lat- 

 eral; pedicels slender and drooping. Lobes of the corolla greenish; 

 hoods white, with 2 teeth; horns with an awl-shaped point extending 

 far out of the hoods. Damp thickets N. and E. 



6. A. variegata L. WHITE MILKWEED. Stem stout, leafless and 

 smooth below, leafy and downy in lines above. Leaves opposite, the 

 middle ones sometimes in fours, petioled, ovate to obovate, cuspidate, 

 smooth on both sides, pale beneath, edges slightly crenate. Umbels 

 1-5, compact, downy, 1-2 in. long; pedicels erect, as long as the 

 peduncles. Corolla white, often purple at the base ; hoods roundish, 

 spreading, a little longer than the thick, awl-pointed, incurved horn. 

 Dry, open woods E. and S.* 



7. A. quadrifolia L. FOUR-LEAVED MILKWEED. Stem slender, 

 1 ^2 ft. or more high, usually leafless below. Leaves in 1 or 2 whorls of 

 4 each, near the middle of the stem, and a pair or two opposite, thin, 

 slender-petioled, 2-4 in. long, ovate-lanceolate, taper-pointed. Umbels 

 ^usually 2, sometimes 1, with slender pedicels. Corolla lobes very pale 

 pink or whitish ; hoods white ; horn short, stout, and bent inward. Dry 

 woods and fence rows. 



m. HOYA R.Br. 



Shrubby, more or less climbing, smooth, tropical plants. 

 Leaves fleshy. Calyx 5-cleft ; corolla 5-lobed, wheel-shaped, 

 its divisions thick and with a waxy look ; crown of 5 spread- 

 ing segments ; pollen masses fastened by the bases. 



1. H. carnosa R. Br. WAX PLANT. Stems long and slender, root- 

 ing and trailing. Leaves oval or nearly so, thick, dark green. 

 Flowers in close umbels, pink or whitish, the corolla lobes covered 

 on the upper surface with minute projections. Cultivated from 

 India as a house plant and in conservatories. 



83. CONVOLVULACE^E. MORNING-GLORY FAMILY 



Usually twining herbs or shrubs, often with milky juice. 

 Leaves alternate (wanting in Cuscuta*), without stipules: 



