230 ASCLKPIADACE.E. 



ASCLEPIAS.— Mir.KWEKn, 



Charndcr of (ha Genus. — Calyx ^-parlcd, persistent, ilio lo1)os small, 

 spread iu}^". Corolla deeply 5-parted, the lubes b(!iit downward toward the 

 stalk ; within the petals are 5 hooded processes, each with an incurved 

 horn, forming what is called the crown, and enclosing the stamen-tube. 

 Stamens ~), inserted in the base of the corolla ; lilaments united into a tube 

 wliich em-loses the pistil ; anthers adherent to the stigma, each with "2 

 vertical c(;lls, each cell containing a flattened pear-shaped mass of pollen. 

 Ovaries 2 ; styles united ; stigma 1, fleshy, H-angled. Follicles 2, one of 

 them often aboi'tive, ovate or somewhat curved, Bi)indle-shaped ; seeds nu- 

 ' erous, tufted with soft silky hairs. 



Perennial herbs with thick, deep-growing roots. Flowers terminal or 

 lateral in sini[)le, many-flowered umbels. 



Ascleplas cornuti Decaisne {A. Si/riaca Liime). — Milhiveod, Silkweed. 



Description. — Hoods of the crown ovate, obtuse, with a lobe or tootli 

 on each side of the short and stout horn. Pods ovate, woolly, and rough, 

 with soft spines. Stem simple, erect, stout, 3 to 4 feet high. Leaves op- 

 posite, oblong-ovate, with short petioles, smooth above, minutely downy 

 beneath, pale green. Umbels many-flowered, terminal and lateral in 

 pedicels shorter than the leaves ; flower.s greenish-j)urple, appearing in 

 midsummer. 



JIahilat. — Common everywhere. 



Asclepias incarnata Limie. — Swamp Milkivml. 



J)cscripli(jn. — Hoods of the crown scaiT.ely iis long as the slender, 

 pointed horn. Pods conunonly smooth and glabrous. Stem erect, brand- 

 ing, 2 to 3 feet high, leafy to the top. Leaves opposite, oblong-lanceolate, 

 acute or pointed, obtuse or obscurely cordate at the base, with short pcti- 

 oles. Umbels numerous, erect, mostly terminal, often in opposite pairs ; 

 flowers roso-purple, appearing in midsummer. 



A somewhat variable species, sometimes more or less haiiy-pubescent, 

 again nearly smooth. 



Habilat. — In wet, swampy places ; common. 



Asclepias tuberosa Linne, — Ihaierjhiiceed — Pleurisy-Pioot. 



Jh'xcriptio)). — Hoods of the crown narrowly oblong, scarcely longer than 

 the nearly erect, slender, pointed horns, bright orange ; corolla lobes 

 greenish-orange. Pods lanceolate, hoary. Stems numerous from a large 

 fleshy rhi/ome 1 to 2 feet high, very leafy. Leaves numerous, scattered, 

 some of them opposite, oblong-lanceolate or linear, sessile or short-petioled. 

 Umbels corymbose at the summit of the stem and branches ; flowers very 

 showy, ajipearing late in summer. 



Ilnbilat. — In dry lields, and along roadsides ; common southward. 



Part Used. — The root of A- tuberosa — United States Pharmacopceia. 

 The roots of A. incarnata and A. cornuti were formerly official, but Avero 



