PENTANDRIA. DIGYNIA. 165 



A genus approaching Cynanchum and Asclepia^. 



Stem herbaceous, twining-, leaves opposite; flowers axil- 

 lary, corvmbose. 



E. alb'ida. 



Uescription. Root perennial. Stem herbaceous, twin- 

 ing, marked with an alternating pubescent line. Leaves 

 opposite, smooth, cordate-ovate, acute, somewhat acumi- 

 nate, sinuate at the base, slighily pubescent on the mar- 

 gin, and sometimes along the nerves, from 1 to 2 inches 

 long, and 1 to 2 w'ide, petiole about an inch. Corymbs 

 axillary, many flowered, upon long peduncles, several 

 often from the same axill; pedicells and caUx pubescent. 

 Calix 5-parted, segments lanceolate-ovate. Corolla 5- 

 parted, greenish or yellowish-white, divisions connivent, 

 erect, linear-oblong, somewhat obtuse. Lepanthium (nec- 

 tary, L.) 5.parted, petaloid, segments divided down to the 

 base, flat, oblong, and truncated, sometimes 4-toothed, 

 the 2 central dentures or incisions terminating in filifornn 

 awns. roUinia (masses of pollen) 5 pair, pendulous, and 

 even as in Asclepias^ suspended to the angles of the stig- 

 ma, cylindric-oblong, much shorter than the antlieri- 

 dium, diaphanous, above united together by a small black 

 cloven tubercle, alternating in the antheroid cells, each 

 pair being common to 2 antheroid bodies. Antheridium 

 ^antheroid bodies) short. and crustaceous, with salient 

 margins, each lobe terminated by a broad, ovate, white, 

 chaffy cusp. Style none. Stigma conic, subbilamellate, 

 seated upon the disk of the antheridium. Follicles 2, 

 short, ovate? not morethan a few lines long? seed comosej 



Habitat. Near Sbepherdstown, on the gravelly banks 

 of the Potomac, Virginia. Abundant in certain localities, 

 on the high sandy banks of the river Scioto, &c. also near 

 Cincinnati, (Ohio) ascending to the height of 8 or 12 feet. 

 Flowering in July and August. An occidental plant, or 

 confined to the western side of the Alleghany mountains, 

 always on alluvial soil. Flowers ochrokucous, with a 

 melhferous scent. Stem like most of the ApociNE.ffi;, 

 affording flax. 



9A3. ASCLEPIAS. i. (Wild-Cotton, Swallow- 

 wort.) 



Calix small, 5-parte(l, persistent. Corolla 

 rotate, mostly reflected. Lepanthium (nectary, 

 L.) simple, 5-parted, segments ovale, cucullate, 

 eachproducing from its base an internal suijulate 

 averted awn, .intheridium 5-parted, cruslace- 



