86 Miller The Dogbanes of tin District of 



finally slightly longer; pedicels 3-5 mm. in length, subulate-bracted at 

 base ; calyx glabrous or pubescent, its segments very narrow, generally as 

 long as corolla tube; corolla white or just perceptibly tinged with pink ; 

 about 4-5 mm. in length, urceolate, its tube conspicuously pentagonal, 

 the throat not narrowed, corolla segments pointed, slightly more than 

 half as long as tube, spreading but not recurved; pods drooping, about 

 90 mm. in length. 



Remarks. Although at first sight Apocynum urceolifer rather closely 

 resembles A. medium, the two plants are readily distinguishable. In 

 habit they are essentially the same, but A. urceolifer is smaller and its 

 stems are usually less strongly tinged with reddish purple, though in all 

 probability neither character is constant. Its flowers are smaller than 

 those of A. medium, and generally pure white, though sometimes faintly 

 tinged with pink. The corolla is more conspicuously pentagonal, and 

 very noticeably contracted at base of segments. The corolla segments 

 are relatively longer and narrower than in A. medium, and distinctly 

 pointed instead of rounded or obscurely pointed at tips. The calyx 

 lobes are generally as long as the corolla tube, and frequently longer, 

 sometimes a little spreading at tips, while in A. medium they are less than 

 half as long as corolla tube and always closely appressed. 



I have seen this plant growing at the type locality only. It is there 

 common on the southeast slope of the hill directly north of the quarry. 

 Mr. W. R. Maxon has collected it at the side of the Military Road, be 

 tween Brightwood, D. C., and Rock Creek. 



Apocynum cannabinum Linnaeus. 

 (PI. II, Figs. 6-7.) 



1753. [Apocynum] cannabinum Linnaeus, Sp. Plant., p. 213. 



1811. A\_pocynum\ pubescens R. Brown, Mem. Wern. Nat. Hist. Soc., I, 



p. 68 (Virginia). 

 1844. [Apocynum cannabinum'] a glaberrimum De Candolle, Prodr. Syst. 



Nat. Reg. Veg., pt. VIII, p. 434 (eastern North America). 

 1881. Apocynum cannabinum Ward, Guide to Flora of Washington and 



Vicinity (Bull. 22, U. S. Nat. Mus.), p. 97. 

 1898. Apocynum cannabinum Britton and Brown, 111. Flora N. United 



States, Canada, and Brit. Poss., Ill, p. 3. 



Type locality. Probably eastern Canada. 



Geographic distribution. Eastern United States and southeastern Can 

 ada. Western limits of range not known. 



Zonal position. Transition and Austral zones. 



Habitat. Fields, thickets, and open woods. 



Characters. Plant robust, 1 to 1.75 m. high, from a perennial, horizon 

 tal, widely spreading rootstock ; branches ascending, glabrous to densely 

 velvety pubescent, green to reddish purple; leaves ascending, mucronate 

 tipped, usually oblong and slightly more rounded at base than at tip, 

 but often, especially the uppermost, tapering equally at each end, and 

 lowermost frequently slightly cordate ; dimensions when full grown about 

 120 x 55 ; upperside of leaves green, varying much in shade, generally 

 glabrous but occasionally velvety pubescent ; underside paler and usually 



