MILK^^'EED FAMILY. 



261 



Order LIT. ASCLEPIADA'CE^. (Milkweed Family.) 



Plants mostly with mill-y-juice. and entire, usually opposite or whorled (rarely scattered) 

 Zeares •without stipules ; Jimcers regular, 5-meroiis and 5-androus : loles cf corolla mostly 

 ■vah-ate in the bud ; tilaments united into a tube -which encloses the pistils, the tube 

 augmented by a croim of 5 lobes or scales, at summit : the anthers united to the stigma 

 and the poTlen in pecuhar vrax-hke masses as described under the first genus ; fiiiit a 

 follicle, seeds compressed and mostly margined and comose. 



An Order remarkable for the pecuhar structure of the flovrers (well illustrated in Prof. 

 Gray"s admirable text-book), and containing a number of plants interesting to the botan- 

 ist, though but few of any economical value. 



1. ASCLE'PIAS, X. Milkweed. 



[The Greek name of ^.iculajnus ; to whom the genus is dedicated.] 



Calyx deeply 5-parted, persistent ; diyisioris small, spreading. Corolla 

 5-parted, reflexed. deciduous. Crown of 5 hooded lobes, seated on the 

 tube of the stamens, each containing an incurTed horn. Stamens 5. in- 

 serted on the base of the corolla ; filaments united into a tube, which 

 encloses the pistil ; ardhers adherent to the stigma, each with two verti- 

 cal cells, tipped with a membranaceous appendage, each cell containing 

 a flattened pear-shaped and waxy poUen-rnass ; the two contiguous pol- 

 len-masses of adjacent anthers forming pairs which hang by their slen- 

 der summits from five small black shining cloven glands, at the angles 

 of the stigma. Ovaries 2, tapering into very short styles ; the large'de- 

 pressed 5-angled fleshy stigma common to the two. Follicles 2, one of 

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

 bricated downwardly all over the large placenta which separates from 

 the suture at maturity, furnished with a long tuft of silky hairs at the 

 hilum. Pe cnnial herbs, with thick and deep roots ; peduncles terminal, 

 or mostly lateral and between the petioles, bearing simple, many-flowered 

 umbels. 



1. A. Conm'ti, Decaisne. Leaves elliptic-ovate, acute, tomentose be- 

 neath ; pods clothed with soft spinous projections and woolly. 



CoKxuTus's AscLEPiAS. Silkwecd. Mihkweed. 



S'ernZ-i feet high, stout, somewhat branched, smoothish. Leaves 6-8 inches lon.^, 

 acute or with a slight point ; contracted at the base into a short but distinct peLide. 

 Vmlels 2-4, axillary near the summit of the stem : common peduncles 2-3 inche.? long ; 

 pedicels 1 -1;2 inches in length, with lance-linear tracts at base ; fioiceis numerous, sweet- 

 scented, many of them abortive : divisions of the corolla ovate, greenish-purple, about 

 one-fourth the length of the pedicels ; lioods of the crown ovate, obtuse, with a lobe or tooth 

 on each side of the stout claw-like horn : follicles few, 3-5 inches long. 



Rich soils : common. PZ. June. JV. September. 



Obs. This, the most common among otir numerous species of the genus, 

 has recently been noticed by a "Western correspondent of one of our agri- 

 cultural papers, as a most troublesome weed, and one exceedingly diiScuIfc 

 to exterminate. It does not bear this character in the Easf. TVhen 

 well established in a fertile soil, its long deep roots will doubtless bo 

 exceedingly difficult to extirpate. The seeds are readily waited to a 

 ^eat distance by means of the copious silky hairs. The plant, when 



