MILKWEED FAMILY. 261 



ORDER LIV. ASCLEPIADA'CE^E. (MILKWEED FAMILY.) 



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

 leaves without stipules j flowers regular, 5-merous and 5-androus ; lobes of corolla mostly 

 valvate in the bud ; filaments united into a tube which encloses the pistils, the tube 

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

 and the pollen in peculiar wax-like masses as described under the first genus ; fruit a 

 follicle, seeds compressed and mostly margined and comose. 



An Order remarkable for the peculiar structure of the flowers (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, L. MILKWEED. 



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



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

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

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

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

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

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

 a flattened pear-shaped and waxy pollen-mass ; 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. Perennial herbs, with thick and deep roots ; peduncles terminal, 

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

 umbels. 



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

 neath ; pods clothed with soft spinous projections and woolly. 



CORNUTUS'S ASCLEPIAS. Silkwecd. Milkweed. 



Stem 3 -4 feet high, stout, somewhat branched, smoothish. Leaves 6-8 inches long, 

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

 Umbels 2-4, axillary near the summit of the stem ; common peduncles 2-3 inches long ; 

 pedicel? 1 -1> inches in length, with lance-linear bracts at base ; 'flowers numerous, sweet- 

 scented, many of them abortive ; divisions of the corotta ovate, greenish-purple, about 

 one-fourth the length of the pedicels ; hoods 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. Fl. Juno. Fr. September. 



Obs. This, the most common among our 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 difficult 

 to exterminate. It does not bear this character in the East. When 

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

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

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



