

ASCLEPIADACEAE. 



[Vol. in. 



9. Asclepias latifolia (Torr. ) Raf. 

 leaved Milkweed. (Fig. 2908.) 



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



Y. 2: 117, 1826. 

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

 A. [amesii Torr. Bot. Mex. Bound. Surv. 162. ' 1859. 



Minutely puberulent when young, glabrous when 

 old; stem stout, usually simple, i°-2'2° 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'-5' 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 

 1' 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 dellexed pedicels, ovoid, acutish, 

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



On dry plains, Kansas to Colorado, Texas and Arizona. 



8. Asclepias Sullivantii Engelm. Sul- 

 livant's Milkweed. (Fig. 2907.) 



A. Sullizantii Engelm.; .\. 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- 

 allj- obtuse and mucronulate at the apex, sub- 

 cordate, rounded or slightly clasping at the base, 

 4'-6' long, I'i'-j' 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, 3'-4' long, 

 usually with blunt processes near the apex. 



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

 souri and Kansas. July-Sept. 



Broad- 



July-Sept. 

 10. Asclepias obtusifolia Michx. 

 Blunt-leaved Milkweed. (Fig. 2909.) 



A. obtusifolia Michx, Fl. Bor .\m, i: 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, 3'-5'long, I'-l^' 

 wide; margins wavy-crisped; primary nerves 

 wide-spreading; umbel nianj'-flowered, usu- 

 ally solitary on the long terminal peduncle, 

 rarelj- with a second shorter-peduncled one at 

 its base; pedicels slender, downy, about i' 

 long; corolla-segments oblong, greenish-pur- 

 ple, about 4" 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 

 decur\ed 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, .\scends to 3000 ft. in Virginia. 

 May- Aug, 



