104 American Midland Naturalist Monograph No. 7 



2. Leaves oblong, longer than broad, 4-20 mm in length. 



3. Capsules 3-3.5 mm long; seeds 2-2.5 mm long; sandy soil, 



rare; Cook, Lake, and Peoria counties. July-Sept 



C. polygonifolia (L.) Small 



3. Capsules 2-2.5 mm long; seeds 1.5 mm long; sandy soil, local. 



June-Sept C. geyeri (Engelm.) Small 



1 . Leaves toothed, at least at the apex. 

 4. Capsules glabrous; seeds wrinkled. 



5. Leaves toothed on both margins; styles 0.6-1 mm long. 



6. Stems usually ascending, glabrous or pilose in lines below; 

 capsules 1.9-2.3 mm long; fields and roadsides, common 

 throughout 111. July-Sept. Nodding Spurge. {E. preslii 



Guss. ; E. hypericifolia sensu auth., non L.] 



C. Tuaculata (L.) Small 



6. Stems usually prostrate; stems pilose; capsules 1.6-1.9 mm 



long; fields and roadsides, rare; Jackson and Lake 



counties C. vermiculata (Raf.) House 



5. Leaves toothed only near tip; styles 0.3-0.5 mm long. 



7. Leaves linear-oblong; seeds with 5-6 sharp ridges; sandy 



or gravelly soil, not common; known from Cook, Henry, 



Lee, Peoria, and St. Clair counties. June-Sept 



C. glyptosperma (Engelm.) Small 



7. Leaves ovate to oblong; seeds without sharp ridges; adv. 



from the western states; Cook Co 



C. serpyllijolia (Pers.) Small 



4. Capsules pubescent; stems prostrate, villous. 



8. Leaves usually somewhat pubescent beneath; seeds 0.8-0.9 

 mm long, minutely pitted and inconspicuously transverse- 

 ly rugose; cultivated ground and roadsides, common. July- 



Oct. Milk Spurge. {E. maculata sensu auth., non L.] 



C. supina (Raf.) Moldenke 



8. Leaves glabrous beneath ; seeds 1 mm long, papillose, ob- 

 scurely wrinkled; sandy soil, local. July-Sept 



C. humistrata (Engelm.) Small 



7. Euphorbia L. — Spurge 

 1 . Glands of the involucres with petal-like appendages. 



2. Leaves not conspicuously white-margined; plants perennial with 

 a deep root; roadsides, fields, and open woods, common 

 throughout 111. June-Sept. Flowering Spurge. \Tithymalop- 

 sis corollata (L.) Small] E. corollata L. 



2. Upper leaves conspicuously white-margined; plants annual; 



waste ground, escaped from cult.; native westward. July- 

 Sept. Snow-on-the-mountain. [Lepadena marginata (Pursh) 



Nieuwl.] E. marginata Pursh 



L Glands of the involucres without petal-like appendages. 



3. Leaves entire. 



