84 Jlil/rr—Tltr Do(/haiics of flic District c>f roI,niiI)la. 



Geograpluc distribulion. — ApocijitiDit sjjeciusinn is at present known from 

 two localities, Sligo and Glen Echo, IxAh in Montgomery County, Mary- 

 land. 



Zorml pddlion. — From its manner ot" occurrence this species appears to 

 l)e a member of the Upper Austral llora. 



Habitat. — Fields and roadsides. 



Ctiaracters. — Plant robust, .75 to 1.2.") m. iiigli, from a perennial hori- 

 zontal rootstock, tirancties ascending, glabrous, green ; leaves ascending) 

 oblong, inconspicuously nuicronate tipped, the lower (mostly about 

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

 end; ui)perside of leaves dark green, glabrous, underside slightly paler 

 and essentially glabrous except along the veins where a line 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-bracted at base; cah/.r 

 very slightly pubescent (this character probabh' 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, canipanulate, its tube dis- 

 tinctly pentagonal, the throat not nariowed; corolla segments i)ointed, 

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

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



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

 A.cannabirixin. The branches are erect, very indistinctly, if at all, diclio- 

 tomous, the leaves ascending, the tlovvers 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 I'ise toward or above the level of the central head 

 they in turn produce flat, tenninal clusters, thus i)rolonging the flowering 

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

 Accompanying the luxuriant inflorescence of this plant is an unusuallj' 

 profuse develo2)ment of fruit, which often hangs in den.se clusters from 

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



Apocynum medium Greene. 



(PI. 11, Fig. :;.) 



1892. Apocjpmin androsivinijoliam Holm, Proc. Biol. Soc. Washington, 



Vil, p. 118 (not of Linnanis 175o). 

 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. 



CItaracter.'f. — Plant slender, seldom more than 1 m. high, from a peren- 

 nial horizontal rootstock; brancli.es dichotomously widely spreading, gla- 



