VAIL: STUDIES IN THE ASCLEPIADACEAE 459 
A single plant found growing on a railroad embankment with 
A. syriaca L., “and A. purpurascens L. a not distant neighbor” 
(Bicknell 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. exaltata (L.) Muhl. than of any of the other related North- 
east American species. The leaves of A. exaltata 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. exal/tata 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, @—/.) 
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 @, I 6; PLATE 17, FIGURE 
1, a-f) and A. amplexicaulis Smith (PLATE 16, FIGURE 3; PLATE 
17, FIGURE 3, a—/). 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 
