Vail: Studies in the Ascleimadaceae 159 



A single plant found growing on a railroad embankment with 

 A. syriaca L., "and A. purpurascens L. a not distant neighbor" 

 (Bickncll in litt). Its leaves resemble closely those of A. purpura- 

 scens L., but with the undulate marginal characters of A. amplexi- 

 caulis Smith ; but the flower and hood characters are nearer those 

 of A. cxaltata (L.) Muhl. than of any of the other related North- 

 east American species. The leaves of A. cxaltata are very thin 

 and acute at each end, those of A. Bicknellii being more nearly of 

 the texture of those of A. syriaca, but without the canescent pube- 

 scence of the latter species. A. cxaltata was not known to grow 

 in the vicinity. 



Asclepias intermedia sp. nov. 



Stems erect, glabrous, purplish, not glaucous, 3 dm. or more 

 high : leaves opposite, on very short but distinct petioles, or pos- 

 sibly the lowest sessile ; blades oblong-elliptical, thinnish, yellow- 

 green and glabrous above, paler and minutely pubescent beneath, 

 the midvein reddish above, the primary veins wide-spreading, also 

 tinged with red, 8-14 cm. long, 3-7 cm. wide, obtuse or the upper 

 ones subcordate at the base, obtuse and apiculate at the apex, most 

 of the margins undulate ; petioles 1—3 mm. long : umbels terminal, 

 2 or more, short-peduncled, or subtended by an upper leaf, 16-24- 

 flowered ; peduncles minutely and sparingly pubescent, 2-8 cm. 

 long ; pedicels 2. 5-3 cm. long, slender, minutely pubescent : calyx- 

 segments ovate, acute, pubescent, especially toward the apex ; 

 corolla green-purple, its segments oblong-lanceolate, 6-8 mm. 

 long ; hoods erect, ovate- lanceolate, obtuse, 5-6 mm. long, pink- 

 ish purple with a darker red or purplish stripe down the back, the 

 lateral margins incurved, each with an erect tooth somewhat above 

 the middle ; horn slender, arising from about the middle of the 

 hood, the tips incurved and meeting over the anthers ; follicles 

 not known. (Plate 16, figure 2 ; plate 17, figure 2, a-f.) 



Lawrence, Long Island, collected by E. P. Bicknell, July 17, 

 1904. Type in the Herbarium of the New York Botanical 

 Garden. 



A possible hybrid. It appears to be intermediate between 

 Asclepias syriaca L. (Plate 16, figure i a, 1 b ; Plate 17, figure 

 1, a-f) and A. amplexicaulis Smith (Plate 16, figure 3 ; Plate 

 1 7, figure 3, a-f). It differs from the latter in its narrower, brighter 

 green leaves that are distinctly petioled and pubescent beneath, and 

 also somewhat less undulate on the margins. The umbels resemble 



