: PENTANDRIA. DIGYNIA. ° 165 
A genus approaching Cynanchum and -4sclepias. : 
Stem herbaceous, twining, leaves opposite; flowers axil- 
: lary, corymbose. 
' £. albida. U 
_ Description. Root perennial. Stem herbaceous, twin- 
‘a ing, marked with an alternating pubescent line. Leaves 
opposite, smooth, cordate-ovate, acute, somewhat acumi- 
nate, sinuate at the base, slightly pubescent on the mar- 
gin, and sometimes along the nerves, from 1 to 2 inches 
long, and 1 to 2 wide, petiole about an inch. Corymbs 
axillary, many flowered, upon long peduncles, several 
often from the same axill; pedicells and calix 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 filiform 
| awns. YVollinia (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 antheri- 
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 
tantheroid 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 more:than a few lines long? seed comose? 
Hapitat. Near Shepherdstown, onthe gravelly banks =~ 
of the Potomac, Virginia. Abundant in certain localities, 
on the high sandy banks of the river Sciota, Kc. 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 ochroleucous, with a— 
melliferous scent. Stem like most of the APociNEA, 
affording flax. 
243. ASCLEPIAS. L. (Wild-Cotton, Swallow- 
wort.) 
Caliz small, 5-parted, persistent. Corolla 
rotate, mostly reflected. -Lepanthium (nectary, — 
L.) simple, 5-parted, segments ovate, cucullate, 
each producing from its base an internal subulate 
averted awn, dntheridium 5-parted, crustace- 
