ASCLEPIADACE^. (mILKWEED FAMILY.) 395 



an incurved horn. Stamens 5, inserted on the base of the corolla: filaments 

 united in a tube which encloses the jjistil : anthers adherent to the stij,nna, each 

 with 2 vertical cells, tipped with a membranaceous appendage, each cell con- 

 taining a flattened pear-shajjcd and waxy ])ollen-niass ; the two contiguous pol- 

 len-masses of adjacent anthers, forming pairs which hang by a slender prolon- 

 gation of their summits from 5 cloven glands that grow on the angles of the 

 stigma,e.\tricated from the cells by the agency of insects, and directing cojjious 

 pollen-tubes into the point where the stigma joins the apex of the styles. 

 Ovaries 2, tapering into very short styles : the large depressed 5-angled fleshy 

 mass which takes the place of stigma common to the two. Follicles 2, one of 

 them often abortive, soft, ovate or lanceolate. Seeds anatropous, flat, margined, 

 downwardly imbricated all over the large placenta, which separates from the 

 suture at maturity, furnished with a long tuft of silky hairs (coma) at the hilum. 

 Embryo large, with broad foliaeeous cotyledons in thin albumen. — Perennial 

 upright herbs, with thick and deep roots : peduncles terminal or lateral and be- 

 tween the petioles, bearing simple many-flowered umbels : flowering in summer. 

 (The Greek name of ^Esculapius, to whom the genus is dedicated.) 



* Leaves opposite {or some of them in No. 5-7 in threes or fours.) 

 ■*- Stem simple or nearly so, Jeafij to the top, and hearing lateral umbels as ivell as a 



terminal one: leaves ovate or oblong : flowers whitish, pinkish, or dull purple. 

 •M- Pods beset with sojl spinous projections : flowers 6" -9" long when open, greenish- 

 purple, numerous in dense umbels. 



1. A. Corntlti, Decaisne. (("ommox Milkweed or Silkweed.) Stem 

 tall and stout.; leaves oval-oblong (4' -8' long), contracted at base into a short 

 petiole, pale, minutely downy beneath, as well as the peduncles, &c. ; hoods of the 

 crown ovate, obtuse, with a lobe or tooth on each side of the short and stout claiv-like 

 horn ; pods ovate, covered with iceak spines and woolly. (A. Syriaca, L., but the 

 plant belongs to this country only.) — Kicli ground, everywhere. 



2. A. Sullivantii, Engelm. Very smooth throughout, tall ; leaves ovate- 

 oblong with a sonif'ivhat heart-shaped base, nearly sessile; hoods obovate, entire, ob- 

 tusely 2-eared at the base outside j^vflowers larger (9' long) and more purple than 

 in the preceding ; pods obscurely soft-spiny, chiefly on the beak, ovate-lanceolate. 



— Low grounds, Columbus, Ohio {Sullivant) to Illinois. 



' ++ Pods even, not ivarty-roughened, mostly glabrous. 



3. A. phytolaccoldes, Pursh. (Poke-Milkweed.) Stem (.3° -.5° 

 high) smootli ; Icures broudly ovale, or the tipper oval-lanceolate and pointed at l/olh 

 ends, short-pet iolid, smooth or slightly downy underneath (5' -8' long); lateral 

 umbels several ; pedicels loose and nodding, nurnerous, long and slender ( 1 ' - 3' long), 

 equalling the pcil uncle, mrfH_y^//«'S longer than the ovate-oblong divisions of tlw (green- 

 ish) corolla; hoods of the crown (white) truncate, the margins 2-toothed at the 

 summit, the horn with a long projecting awl-shaped jwint ; pods minutely downy. 



— Moist co])ses ; flowering early in summer. — Flower 6' long. 



4. A. purpurascens, L. (Purple M.) Stem rather slender (1° -3° 

 high) ; leaves elliptical or ovate-oblong, the uj)per taper-pointed, minutely velvety- 

 downy underneath, smooth above, contracted at the base into a short petiole ; pedicels 



