ASCLEPIADACEAE. 



[Vol. III. 



8. Asclepias Sullivantii Engelm. Sul- 



livant's Milkweed. (Fig. 2907.) 

 A. Sullivantii Engelm.; A. Gray, Man. 366. 1848. 

 Glabrous throughout; stem stout, simple, or 

 sometimes branched above, 2-4 high, leafy to 

 the top. Leaves thick, sessile, or on petioles 

 less than i // long, oblong or ovate-oblong, usu- 

 ally obtuse and mucronulate at the apex, sub- 

 cordate, rounded or slightly clasping at the base, 

 4 / -6 / long, 1%'-$' wide, the primary nerves 

 very wide-spreading; umbels terminal and some- 

 times also in the upper axils, many-flowered; 

 peduncles shorter than the leaves; corolla- seg- 

 ments oval-oblong, 5 // -6 // long, purplish; col- 

 umn very short and thick; hoods oval, obtuse or 

 truncate, gibbous at each side near the base, 

 longer than the anthers and the subulate in- 

 curved horn ; follicles erect, glabrous, 2> , ~A / lng, 

 usually with blunt processes near the apex. 



In moist soil, Ohio to Minnesota, Nebraska, Mis- 

 souri and Kansas. July-Sept. 



g. Asclepias latifolia (Torr. ) Raf. Broad- 

 leaved Milkweed. (Fig. 2908.) 



Asclepias obtusifolia var. latifolia Torr. Ann. Lye. N. 



Y. 2: 117. 1826. 

 Asclepias latifolia Raf. Atl. Journ. 146. 1832-33. 

 A. famesii Torr. Bot. Mex. Bound. Surv. 162. 1859. 



Minutely puberulent when young, glabrous when 

 old; stem stout, usually simple, i-2^ high, very 

 leafy. Leaves very thick, oval to orbicular, sessile 

 or nearly so, commonly broadly emarginate and 

 mucronulate at the apex and cordate or subcordate 

 at the base, 4 / -6 / long and nearly as wide, primary 

 nerves very wide-spreading; umbels 2-4, many- 

 flowered, short-peduncled in the upper axils or 

 rarely terminal; pedicels slender, canescent, nearly 

 i / long; corolla-segments ovate, acute, 4 // -6 // long, 

 greenish; column short and thick; hoods truncate, 

 about equalling the anthers, the horn projecting 

 from a short crest over the edge of the stigma; 

 follicles erect on deflexed pedicels, ovoid, acutish, 

 2 / -3 / long, about i / thick. 



On dry plains, Kansas to Colorado, Texas and Arizona 



July-Sept. 



10. Asclepias obtusifolia Michx. 

 Blunt-leaved Milkweed. (Fig. 2909.) 

 A. obtusifolia Michx. Fl. Bor Am. 1: 115. 1803. 



Nearly glabrous, pale green, somewhat glau- 

 cous; stem stout, erect or ascending, 2-3 high. 

 Leaves sessile or short-petioled, oblong or ovate- 

 oblong, obtuse and mucronulate at the apex, 

 cordate-clasping at the base, tfs' long, i'-iJ^' 

 wide; margins wavy-crisped; primary nerves 

 wide-spreading; umbel many-flowered, usu- 

 ally solitary on the long terminal peduncle, 

 rarely with a second shorter-peduncled one at 

 its base; pedicels slender, downy, about 1/ 

 long; corolla-segments oblong, greenish-pur- 

 ple, about \" long; column thick; hoods pink, 

 nearly truncate and toothed at the summit, 

 shorter than the subulate incurved horn, longer 

 than the anthers; follicles erect on the stout 

 decurved fruiting pedicels, downy, 4 / -6 / long. 



In dry fields, mostly in sandy soil, Maine to 

 Florida, west to northern New York, Minnesota, 

 Kansas and Texas. Ascends to 3000 ft. in Virginia, 

 May-Aug. 



