100. ASCLEPIADACEAE 185 



Cook, Kankakee, and McHenry counties 



A. ovalifolia Dec. 



7. Leaves glabrous or nearly so. 



10. Fruiting pedicels erect or recurved; leaves lanceolate, 

 acuminate; corolla-lobes 3-5 mm long. 

 11. Flowers rose-purple, rarely whitish; leaves all 

 opposite; moist ground, roadside ditches, river 

 banks, or in swamps, common. July-Aug. 



Swam]) Milkweed A. incarnata L. 



1 1. Flowers pink or white; leaves thin. 



12. Flowers pink; median leaves u.sually whorled; 

 seeds with a coma; dry woods, chiefly in w. 



and s. 111. May-Jime A. quadrijolia Jaccj. 



12. Flowers white; leaves all opposite; seeds 

 usually without a coma; wet ground in 



woods, s. 111., rare. June-Aug 



A. perennis Walt. 



10. Fruiting pedicels deflexed; corolla-lobes 6-8 mm long. 



13. Umbel loose, the pedicels drooping, 2.5-5 cm 



long; leaves thin, elliptic-lanceolate, acuminate; 



corolla-lobes obtusi^h, greenish, the hoods white 



or pink; stem 1-1.5 m tall; woods. June-July. 



Poke Milkweed [A. phytolaccoides Pursh] 



...A. e.xaltata (L.) Muhl. 



13. Umbel compact, the pedicels erect or ascending, 

 1-2 cm long; leaves oval, firm, obtuse and 

 mucronate, or acute; corolla-lobes white, acute, 

 the hoods puiplish; stem 30-90 cm tall; sandy 

 soil, not common; s. 111., extending northward 

 to Wabash and St. Clair counties. June-July. 



White Milkweed A. varicgata L. 



Hoods without a horn; flowers sfreenish. 



14. Umbel solitary, terminal; plants hirsute; leaves lanceolate, 

 acutish ; stem 10-30 cm tall; dry ground, in the n. part of the 



state. June-Aug A. lanuginosa Nutt. 



14. Umbels several; plants puberulent or glabrate; stem 30-90 cm 

 tall. 

 15. Umbels peduncled; leavej alternate, linear-lanceolate, acu- 

 minate; hoods entire; roadsides and fields. July-Aug. 



A. Iiirtella (Pennell) Woodson 



15. Umbels sessile; leaves chiefly opposite. 



16. Leaves lanceolate; umbels many-flowered; pedicels 

 pubescent; hoods entire; roadsides and fields, local. 



June-Aug A. viridiflora Raf. 



16. Leaves linear; umbels 10- to 15-flowered; pedicels 

 puberulent; hoods 3-toothed; dry upland woods; 

 Quincy, Adams Co., R. Brinker 3495. [Asciepias 

 stenophylla A.Gray] A. angustifolia Nutt. 



