ai8 



PENTANDRIA DIGYNlA. 



» 



bellis terminallbus 



um 

 ped 



what 



gi 



iindeT 



neath: umbels 



pedicellisquc nil- I ped 



bescentibus 



E 



h 



Sp. p(. I. p. 1265. Walt, p 

 A. lij'brida, Mich. l.p. 115. 



pubescent 



and pedicel 



Pursh, 1. p. 181. 



Root perennial. Stem herbaceous, simple, erecl, 2 — 2i feet high^ 

 terete, with two pubescent lines, tiark purple. Leaves sHghtlv acu- 

 minate, strongly veined, with the veins and margins pubescent j pe- 

 tioles half an inch long, pubescciit. Umbels 1—6, naked, at tlie sum- 

 mit of the stem ; peduncles and pedicels about an inch long, with a 

 small, setaceous, caducous leaf at the base of each pedicel. Calyx 

 small, 5 parted ; segments subulate, hairy, green, rcflexed. Corolla 

 5 parted? segments broad, lanceolate, ghibroiis, 3—4 times as lon;r as 

 the calyx, green on the outer surface, white on the inner. J\"ecf(fr!/ 

 or stamimal crown composed of 5, fleshy, obtuse, white leaves shorter 

 than the petals ; leaves involute, sligVitly impressed on the back, 

 bearing from tlie hollow centre a small hoin, acute, incurved. Fila- 

 mentsy 5, sessile, cohering, with the membranous margins rcfiected, 

 and the summit also membranous, inflected, containing a cell or sack 

 at each interior angle, purple at base, and white at the summit. Foi- 

 len masses 10, yellow, solid, transparent, 3 jointetl, pendulous, the 

 lower joint? punctate, attached to a pentangular, central corpuscle, 

 fi at each angle, and hanging in the cells of the filaments : the 3 

 masses at each angle are not inserted into the 2 cells t-f one, but into 

 the approximating cells of adjoining filaments. Germs 2, small, conic, 



united at base, covered by the corpuscle to which the pollen masses 

 are attached. Styles short. Stigmas simple, obtuse. FoUide lance- 

 olate, smooth, opening at one side. Seeds flat, orbicular, slightly 

 winged, attached to a loose, central receptacle, and crowned at the 

 summit with a long tuft of silky hair. 



The essential parts of this description will apply to all of the plants 

 that really belong to the genus Asclepias. The species vary in the co- 

 lour, figure, and proportional size of the corolla, stamineal crown, horn 

 and corpuscle, and from these the best specific characters w ill perliaps 

 be ultimately derived ; at present the leaves supply more obvious and 

 sufficient characters. 



Physiological Botanists still differ as to the uses, functions, and 

 even names of the parts of the flower in the complex structure of 

 this natural order of plants ; even the place which tlie Asclepiadeffi 

 ought to occupy m the artificial system of Linn*us has been a subject 

 of controversy. But their connection with the Apocyneaj, most of 

 which are manifestly pentandrous, seems to require their location in 

 this class. 



All the species of Asclepias are ornamental, and the pappus has 

 been applied to purposes of domestic ceconomy. For ornament this 

 species, the A. obtusifolia, laurifolia, paupercula and parviflora merit 



particular attention ; while the A. amolcxicaulife sppms to nmduce tin' 



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