DICOTYLEDONS. 187 



comose. Most species bloom late in the season. [The poUeu 

 masses are easily withdrawn from the anther-sacks, and are 

 often found attached to the legs of insects which visit the 

 flowers for nectar and fertilize the pistils in their struggles 

 to free themselves from the sticky anthers.] 



I. ASCLEPIAS. 



Perennial herbs ; stems erect or decumbent ; leaves alter- 

 nate, opposite or whorled ; flowers in terminal or lateral 

 umbels ; calyx 5-i)arted, small, lobes acute ; corolla rotate, 

 deeply 5-parted, reflexed, crown of 5 hoods, eacli containing 

 an incurved, horn-like appendage ; anthers tipped with an 

 inflexed membrane ; pollen masses 10, each i)air occupying 

 the contiguous cells of adjacent anthers ; follicles large, 

 many-seeded, seeds flat, usually comose. 



1. A. TUBEROSA L. Buttp:rfly-weed. Stem stout, erect or 

 ascending, branched above, liirsute, very leafy, 1-2 ft. high ; leaves 

 alternate or the lower opposite, oblong to lanceolate or linear, acute 

 at the apex, rounded or cordate at the base, short-petioled, pubescent ; 

 umbels nunierons, corymbose, many-flowered ; peduncles shorter than 

 the leaves ; pedicels erect, about 1 in. long, pubescent ; corolla yel- 

 lowish-orange, crown bright orange, hoods erect, longer than the 

 slender horns, and twice as long as the stamens ; follicles erect, fusi- 

 form, pubescent, seeds comose. June-August. Common on dry 

 soil. 



2. A. vAHiEGAT.v L. WuiTE AIiLKWEEn, Stem stout, leafless 

 and smootli below, li^afy and })nbescent in lines above ; leaves oppo- 

 site, the middle ones sometimes in 4's, petioled, ovate to obovate, 

 cuspidate, smooth on both sides, pale beneath, edges slightly ere n ate ; 

 umbels 1-5, compact, pubescent, 1-2 in. long; pedicels erect, as long 

 as the peduncles; corolla white, often }>urple at the base; hoods 

 rouiulish, spreading, longer than the ]uu'})lish gymnostegium, and a 

 little longer tiian the thick, awl-pointed, incurved horn ; follicles 

 erect, downy, seeds comose. May-fJun«'. Dry, open woods. 



']. A. AMI'LEXirAlLIS Michx. PiNE-HAUKEN AsCLEPIAS. StCUlS 



recurved, ascen<ling or decumhent, smooth and glaucous, 1-2 ft. long; 

 leaves opjiosite, very thick, ovate, obtuse at the apex, cordate and 

 clasping at tlie base, veins white and ]u-ominent ; umbels ^J-O, many- 

 flowered; pe<luncles half the length of the leaves, longt'r than the 

 slender pedicels; corolla ash-colored; lioods white, longer than the 



