84 Miller The Dogbanes of the Dixh'iH <>f Cnlinubia. 



Geographic distribution. Apocynum spedomtm is ut present known from 

 two localities, Sligo and Glen Echo, both in Montgomery County, Mary 

 land. 



Zonal position. From its manner of occurrence this species appears to 

 be a member of the Upper Austral flora. 



Habitat. Fields and roadsides. 



Characters. Plant robust, .75 to 1.25 in. high, from a perennial hori 

 zontal rootstock, branches ascending, glabrous, green ; leaves ascending? 

 oblong, inconspicuously mucronate tipped, the lower (mostly about 

 70-80 x 35-45) slightly rounded at base, the uppermost tapering at each 

 end; upperside of leaves dark green, glabrous, underside slightly paler 

 and essentially glabrous except along the veins where a fine pubescence 

 may be detected; petioles 4-8 mm. in length, slender above, shorter and 

 more robust below, finely pubescent on underside ; inflorescence in large 

 compact, flat-topped strictly terminal cymes of very many erect flowers, 

 the cymes at first exceeded in length by the leaves, but afterwards slightly 

 longer; pedicels about 4 mm. in length subulate-braeted at base; calyx 

 very slightly pubescent (this character probably variable), its segments 

 narrow, half as long as corolla tube ; corolla white or very faintly tinged 

 with pink inside, about 6-7 mm. in length, campanulate, its tube dis 

 tinctly pentagonal, the throat not narrowed ; corolla segments pointed, 

 slightly more than half as long as tube, spreading but not recurved ; 

 pods drooping, about 70 to 120 mm. in length. 



Remarks. In this plant the habit is almost precisely similar to that of 

 A.cannabinum. The branches are erect, very indistinctly, if at all, dicho- 

 tomous, the leaves ascending, the flowers upright, and the inflorescence 

 is in distinctly flat-topped cymes, the central of which, at the end of the 

 main stem, is usually but not always the largest, and earliest to flower. 

 As the lateral branches rise toward or above the level of the central head 

 they in turn produce flat, terminal clusters, thus prolonging the flowering 

 season from before the middle of June nearly to the middle of August. 

 Accompanying the luxuriant inflorescence of this plant is an unusually 

 profuse development of fruit, which often hangs in dense clusters from 

 the lower part of a cyme which above is still a mass of flowers. 



Apocynum medium Greene. 

 (PL II, Fig. 3.) 



1892. Apocynum androsxini/olium Holm, Proc. Biol. Soc. Washington, 



VII, p. 118 (not of Linnaeus 1753). 

 1897. Apocynum medium Greene, Pittonia, III, p. 229, December, 1897. 



Type locality. Vacant lots bordering 12th St., in Brookland, D. C. 



Zonal position. Apocynum medium will probably be found to occur 

 throughout the upper Austral zone of the eastern United States. It is to 

 be looked for also in the lower part of the Transition zone. 



Habitat. Dry, open ground. 



Characters. Plant slender, seldom more than 1 in. high, from a peren 

 nial horizontal rootstock; branches dichotomously widely spreading, gla- 



