166 American Midland Naturalist Monograph No. 2 



5. Stems trailing, pilose; leaflets nearly orbicular, obtuse; stipules ovate- 

 lanceolate, ciliate; woods, s. 111., extending northw. to Clark and St. 



Clair counties. Aug.-Sept. [M. michaiixii Vail} 



D. rotundijolhim (Michx.) DC. 



5. Stems erect or ascending. 



6. Joints of the pods rhombic, longer than broad. 



7. Leaflets obtusish, ovate or oval, somewhat rough-pubescent on 

 both surfaces, pale and reticulate beneath, about the same length 



as the petiole; stem pubescent; open woods. July-Aug 



D. canescens (L.) DC. 



7. Leaflets acuminate, longer than the petiole. 



8. Leaves and stem glabrous; bracts of the inflorescence not ciliate; 



woods throughout 111., except the n. counties. July-Sept 



D. bracteosum (Michx.) DC. 



8. Leaves and stem glabrous; bracts of the inflorescence not ciliate; 



open woods. July-Aug D. longijolium (T. & G.) Smyth 



6. Joints of the pods oval; leaflets lanceolate or ovate-lanceolate, reticu- 

 late beneath, pilosulous; stem uncinate-pubescent; in woods and 

 along roads throughout 111. July-Aug D. illinoense Gray 



4. Stipules small, inconspicuous, setaceous, usually soon deriduous. 



9. Leaves sessile or nearly so, the leaflets linear or lanceolate, obtusish, 

 thickish, reticulate, pubescent beneath; stem puberulent; pods 1-3- 

 jointed; open woods. July-Sept D. sessilijolium (Torr.) T. & G. 



9. Leaves petioled. 



10. Pods distinctly stipitate, the stipe exceeding the calyx. 

 11. Stem and leaves glabrous or nearly so. 



12. Leaflets ovate or broadly oval, pale beneath; flowers pink, 9- 



14 mm. long; woods, chiefly in s. III. Aug.-Sept 



D. laevigatum Nutt. 



12. Leaflets elliptical-lanceolate; flowers violet-purple, 5-8 mm. 



long; open woods, common. July-Sept 



D. paniciilatum (L.) DC. 



11. Stem and leaves pubescent; flowers purple, 6-9 mm. long. 



13. Leaflets ovate, thick, coriaceous, velutinous beneath; wooded 



slopes and ridges, s. 111., not common. Aug.-Sept 



D. viridiflorurti (L.) Beck 



13. Leaflets elliptical or oval, appressed-pubescent beneath; dry 

 soil, usually in open woods. Aug.-Sept ...D. dillenii Darl. 



10. Pods short-stipitate or sessile, the stipe not exceeding the calyx- 

 lobes. 

 14. Flowers showy, 8-12 mm. long, in dense panicled racemes; joints 



of the pods 3-5; prairie soil. July-Sept 



D. canadense (L.) DC 



14. Flowers small, 2-6 mm. long, in loose panicled racemes; joints 

 of the pods 1-3. 



