938 ASCLEPIADACEAE 



disposed. Calyx inferior : tube very short or none : sepals imbricated or separate 

 in the bud. Corolla campanulate, urceolate, rotate or funnelform, 5-lobed : 

 lobes commonly reflexed. A 5-lobed crown (corona) is borne between the corolla 

 and the stamens, and aduate to the one or the other, or to both. Stamens 

 5, adnate to the corolla, usually near its base. Filaments mostly monadel- 

 phous, or distinct. Anthers attached at the base, introrse, 2-celled, converging 

 around the stigma, sometimes united to each other : sacs tipped with an inflexed 

 or erect scarious membrane, or unappendaged at the top, sometimes appendaged 

 at the base. Pollen coherent into waxy or granular masses, one or rarely 2 such 

 masses in each sac, connected with the stigma in pairs or fours by 5 glandular 

 corpuscles alternate with the anthers. Disk none. Gynoecium of 2 carpels. 

 Styles 2, connected at the summit by the peltate-discoid stigma. Ovules numer- 

 ous in each cavity, mostly anatropous, pendulous. Fruit of 2 several-many- 

 seeded follicles. Seeds compressed, usually appendaged by a long coma. Endo- 

 sperm cartilaginous. Embryo nearly as long as the seed : cotyledons flat. 



Pollen granular, the grains grouped in 4's : caudicles spoon-shaped, without a corpuscle. 



1. Pekiploca. 

 Pollen united in 2 waxy masses (pollinia): caudicles united by a corpuscle. 

 PoUinia pendulous. 



Crown double, the outer a shallow ring, the inner consisting of 5 fleshy hood- 

 like scales. 2. Philibertella. 

 Crown single. 



Erect, ascending or procumbent herbs. 



Corolla oblong-campanulate : lobes erect. 3. Podostigm.^. 



Corolla rotate, the lobes spreading or reflexed in anthesis. 

 Corolla-lobes reflexed during anthesis. 

 Anther-wings corneous. 



Hoods of the crown involute-concave, entire or auricled below 

 the middle, crestless within, or in Acerntes angiislifolia 

 with an obscure crest-like midrib. 4. Acerates. 



Hoods of the crown erect, involute or complicate, each with 



an acute horn-like process within. 5. Asclepias. 



Anther-wings membranous or papery : hoods of the crown ob- 

 long-clavate, ascending and incurved over the anthers, with 

 a narrow, lamelliform, pointless crest within. 6. Anantherix. 



Corolla-lobes erect-spreading during anthesis: hoods of the crown 

 pendulous or saccate at the base, curved upwards, obtuse, 

 crested within, at least in the upper part. 7. Asclepiodora. 



Twining vines. 



Crown-lobes entire or more or less .3-lobed. 



Lateral margins of the crown-lobes not involute : leaf-blades rela- 

 tively narrow and not cordate at the base. 8. Metastelma. 

 Lateral margins of the crown-lobes involute: leaf-blades cordate 



at the base. 9. Rouliniella. 



Crown-lobes notched or 2-awned at the apex. 



Crown-lobes 2-awned at the apex : follicles stout, strongly and 



sharply angled. 10. Gonolobus. 



Crown-lobes merelj^notched at the ape.x ; follicles slender, essen- 

 tially terete. 11. Seutera. 

 Pollinia horizontal or nearly so : stigma sharply .^-angled, depressed. 12. Vincetoxicum. 



1. PERIPLOCA L. 



Woody twining plants. Leaves opposite : blades entire. Flowers in umbels. Calyx 

 5-lobed, glandular within. Corolla deeply 5-lobed, the lobes obtuse, dextrorsely rotate, 

 villous on the inner surface. Crown adnate to the base of the corolla, with 10 broad or 5 

 slender elongated, entire or lobed scales or appendages. Filaments short, free, converging 

 at the short appendiculate apex. Pollen granular, the grains aggregated into groups of 4 

 each. Follicles slender, glabrous, generally united at the apex. Seeds comose. 



1. Periploca Gra^ca L. Plant glabrous. Leaf-blades ovate-oblong, acute, paler 

 beneath than above : umbels cymose : jiednncles shorter than the leaves : corolla-lobes dull 

 brownish or greenish, each with a darker line down the middle and a whitish spot at the 

 base within : appendages of the crown slender, ligulate, 2-toothed at the apex. 



Escaped, Massachusetts to Kansas and Florida. Native of Syria and the Grecian Islands. Silk Vine. 



2. PHILIBERTELLA Vail. 



Twining perennial caulescent herbs, or partly shrubby plants. Leaves opposite : 

 blades linear or cordate-hastate. Flowers in umbels, often fragrant and showy. Calyx 

 small : lobes 5, acute. Corolla campanulate or rotate, a sliallow entire or undulate ring 

 forming an outer crown in its throat : lobes 5, longer than the tube. Inner or stamineal 



