ASCLEPIADACEAE 943 
2a. Asclepias Rólfsii Britton. Similar to the two preceding species in habit. Leaves 
rather numerous; blades thinnish, mainly oblong, sometimes narrowly so, when broad 
often fiddle-shaped, truncate or cordate at the base: umbels in terminal leafy cymes: 
calyx-lobes nearly 3 as long as the corolla-lobes, pubescent : corolla orange; lobes oblong, 
6-7 mm. long: column stout: hoods erect, broadly oblong, 5-6 mm. long, considerably 
exceeding the horns. 
In pine lands, southern peninsular Florida. Spring and summer. 
3. Asclepias Curtissii A. Gray. Stems decumbent or suberect, 5 dm. long or more, 
from a much thickened tuberous rootstock, simple or branched, puberulent, purplish : 
leaf-blades broadly oblong or some round-oblong, 3-5 cm. long, truncate, rounded or 
some of the lower ones acutish at the base, apiculate or retuse at the apex, glabrous: 
umbels 2-several in the axils of the upper leaves, many-flowered, on peduncles 2-4 cm. 
long: pedicels very slender, 1-1.5 cm. long, puberulent : corolla greenish, purple-tinged on 
the outside; lobes 6 mm. long, oblong-lanceolate : column scarcely apparent : hoods erect, 
distinctly stalked, white, the keel purple-tinged, 5 mm. high, exceeding the anthers, acute 
at the apex, the ventral margins rounded and infolded, distinctly clawed at the hastate base : 
horn short, subulate, affixed to about the middle of the hood, horizontally exserted and 
incurved over the anthers : anther-wings very short, triangular-sagittate, angled and sharply 
salient at the entire base : follicles 1 dm. long, long-attenuate at the apex, puberulent : seeds 
8 mm. long, erose-undulate on the margin : coma 3 em. long. 
In sandy soil in the scrub, Florida. Spring to fall. 
4. Asclepias latifólia (Torr.) Raf. Stems usually simple, 3-8 dm. high, stout, 
minutely puberulent when young, glabrous when old, very leafy : leaf-blades broader than 
long, commonly broadly emarginate and mucronulate at the apex and cordate or subcordate 
at the base, 7-15 em. long and nearly as wide, the primary nerves notably wide-spreading : 
umbels 2-4 or more, short-peduncled in the axils of the upper leaves and rarely terminal, 
many-flowered, often 8 cm. in diameter: pedicels canescent, nearly 3 cm. long: corolla- 
lobes ovate, acute, 7-9 or 10 em. long, greenish : column short and thick : hoods truncate, 
about equalling the anthers, the horn broadly triangular, the exserted subulate apex pro- 
jecting over the acute ventral sides of the hood and exserted overthe stigma : anther-wings 
notched or somewhat auriculate, spreading at the base : follicles erect on deflexed pedicels, 
ovoid, acutish, 6 cm. long, glabrate: seeds 8 mm. long, glabrous, marked with fine broken 
ridges and dots, the wing-like margin narrow : coma rather stiff, 2.5-3.5 cm. long. 
On dry plains, Kansas to Colorado, Texas and Arizona. Summer and fall. 
5. Asclepias amplexicaülis J. E. Smith. Stems glabrous, 3 dm. to 1 m. high: 
leaves opposite or rarely in fours at the base of the stem ; blades sessile, oblong or elliptic, 
6-12 em. long, 3.5-8 em. wide, clasping at the base, rounded, retuse and apiculate at the 
apex, wavy-margined, glabrous, lighter and glaucous beneath : peduncles much longer than 
the leaves, terminal, solitary or rarely two: umbels loosely many-flowered : pedicels 
slender, 2-3 cm. long: flowers rather large and showy: corolla-lobes greenish or dull 
greenish purple, 6-10 mm. long, acutish : hoods erect, flesh colored or reddish, sessile at the 
summit of the short column, slightly gibbous or saccate at the base, truncate at the undu- 
late-erose and toothed summit, as high as or somewhat exceeding the anthers: horn falcate, 
angled above the middle, strongly inflexed and attenuated at the long-exserted apex : anther- 
wings conspicuously bicorniculate at the base: follicles 10-16 cm. long, acute or long-atten- 
uate: seeds 7 mm. long, glabrous, marked with minute broken lines, the margins rather 
Den paler than the body : coma 5 cm. long or more, very soft and silky. [A. obtusifolia 
lichx. ] 
In dry or sandy soil, New England to Nebraska, Florida and Texas. Spring and summer. 
6. Asclepias humistràta Walt. Stems glabrous and glaucous throughout, decumbent 
from a long tuberous root, simple or branched above, stout and thick, succulent, 3-6 dm. 
long : leaves rather crowded, usually decreased in size at the base or toward the summit of 
the stem, the successive pairs parallel; blades sessile, vertical, nearly alike on both sides, 
ovate, 5-13 em. long, 4-10 em. wide, cordate-clasping and somewhat auriculate at the base, 
obtuse at the apex, thick and succulent when fresh, becoming thin and papery when dry, 
sometimes undulate on the margins, the whitish transverse and reticulated veins turning 
reddish : peduncles as long as or commonly shorter than the leaves: pedicels slender, about 
2 cm. long : corolla-lobes dull greenish purple, 7 mm. long: column short : hoods whitish, 
about 5 mm. high, obovate-truncate, rounded at theapex, the ventral margins with a broad 
rounded tooth on each side about the middle: horn broad, flat, angular-arcuate, only 
slightly exceeding the hood : anther-wings obscurely notched at the base : follicles 1-1.5 
dm. long, 1.5-2 cm. wide, attenuated and acutish at the apex, glabrous and glaucous : 
