ASCLEPIADACE.E. (MILKWEED FAMILY.) ^41 



base, entire at summit, involute-cotxcnve ; thr falcate or suhilate horn free at 

 or below the middle of the horn, and incurved or in flexed over thr stigmatic 

 disk. 



8. A. OValifolia, Decaisne. Tomentidose-pubescent : stem rather shudcr : 

 leaves thinnish, from ovate or oval to ovate lanceolate, mostly at'Utc, rounded 

 at base, distinctly petioled, the midrib and veins slender, the vcinlets reticulated : 

 umbels few, loosely 10 to 18-flowered, on peduncles which seldom eiptal the jiedi- 

 eels: corolla greenish-white with i)urpl:sh outside: hoods oval or broadhf oblong 

 in outline, not auriculate at base, the inner margins below the middle rxttndcd into 

 a large acute tooth or lobe; the horn broad and rather short: anther-wings rounded 

 and mostly entire. — From the Dakotas to the Saskatchewan and N. Illinois. 



9. A. Hallii, Gray. Puberulent-glabrate: stem stout: leaves thirkish, ovale- 

 lanceolate or oblong-lanceolate with rounded base and rather acute npex, 

 short-petioled, the stout midrib and straight veins prominent underneath : umbeirt 

 few and corymbose, many-flowered, on peduncles somewhat longer than the jyedi- 

 eels: corolla greenish-white and purplish: hoods elongated-oblong in outline, 

 entire, hastatel// 2-gibbous above the narrower base, a little surpassing the sickle- 

 shaped horn: anther-wings unappendaged at base. — Proc. Am. Acad. viii. 69. 

 .1. ovalifolia of Fl. Colorado, 114. Colorado. 



•M- ++ Follicles erect on erect vedicels : leaves usuallg verticillate, filiform, 



glabrous. 



10. A. vertieillata, L. Stems a foot or two high, slender, very leafy : 

 leaves mostly in whorls of 3 to 6, or some scattered, filiform-linear, with revo- 

 lute margins : umbels numerous, small, many-flowered, on peduncles longer 

 than the pedicels: corolla greenish-white: hoods white, broadly ovate and 

 entire, with somewhat auriculate involute base, barely ecpialling the antliers, 

 much shorter than their elongated-subulate falcate-incurved horn. — In dry 

 soil, from New Mexico and Colorado to Nebraska, and eastward across the 

 continent. 



Var. pumila, Gray. A span or more high, many stemmed from a fasci- 

 cled root: leaves much crowded, filiform : peduncles seldom lon;:or than tlie 

 pedicels. — Proc. Am. Acad. xii. 71. From New Mexico to Nebnuska and 

 Kansas. 



§2. Anther-wings ividening to the broadli/ rounded base and consjurunu.s '/ i/u- 

 riculate-notched just above it: hoods sessile, with a narrow tcholli/ adnate inter- 

 nal crest terminating in a minute horn: pollinia short and thick, arcuate-ol>orate. 



11. A. Stenophylla, Gray. Puberulent, but foliage glabrous: stem.s 

 slender, 1 or 2 feet iiigh, simple : leaves long and narrowly linear, witii sca- 

 brous and more or less revolute margins and a strong midrib; the upper 

 alternate and the lower opposite: umbels several, 10 t«» ir)tlowered: flowers 

 greenish : hoods whitish, erect, equalling the anthers, condu|)licateconcave, 

 the base of each inner margin appendag:ed by a cuneate erosely truncate lol>e, 

 the apex 2-lobed and the narrow internal crest exscrted in the sinu."* in the 

 form of an intermediate tooth : interior crown of 5 very small 2-lobed pro- 

 cesses between the bases of the anthers: follicles long-acuminate, erect on 

 the ascending pedicel. — Proc. Am. Acad. xii. 72. Aremtes angustifoiia, 

 Decaisne. From Colorado and X. Texa.s to Nebraska and W. Arkansa*. 



16 



