136 American Midland Naturalist Monograph No. 7 



pubescent; in woods and along roads throughout 111., 



except the northern counties. July-Aug 



D. illinoense A. Gray 



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



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



obtusish, thickish, reticulate, pubescent beneath; stem 



puberulent; pods 1- to 3-jointed; open woods. July-Sept. 



D. sessilifolium (Torr. ) T. & G. 



9. Leaves petioled. 



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

 1 1 . 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. 111. Aug.- 

 Sept D. laevigatum Nutt. 



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



mm long; open woods, common. July-Sept 



D. paniculatum (L.) DC. 



1 1 . Stem and leaves pubescent ; flowers purple, 6-9 mm 

 long. 



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



wooded slopes and ridges, s. 111. Aug.-Sept. [D. 



viridiflorum sensu auth., non (L.) DC.] 



D. nuttallii (Schindl.) Schubert 



13. Leaflets elliptical or oval, appressed-pubescent be- 

 neath; dry soil, usually in open woods. Aug.-Sept. 



[D. dillcnii sensu auth., non Dark] 



...D. glabellum (Michx.) DC. 



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

 calyx-lobes. 

 14. Flowers showy, 8-12 mm long, in dense panicled ra- 

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



D. canadc7ise (L.) DC. 



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



joints of the pods 1-3. 



15. Leaflets scabrous, softly pubescent, pale green and 



reticulate beneath, 2.5-5 cm long; stem puberulent; 



coi'olla 5-6 mm long; sandy soil in open woods, 



chiefly w. and s. 111. Aug.-Sept 



D. rigidum (Ell.) DC. 



15. Leaflets not scabrous, 1-2.5 cm long, glaucous be- 

 neath; corolla 2-4 mm long. 

 16. Stem and leaves glabrous; wooded slopes and 



ridges, locally in central 111. July-Sept 



D. marilandicum (L.) DC. 



16. Stem pubescent; leaves more or less pubescent; 

 open woods in s. 111. July-Sept. [D. obtusum 



(Muhl.) DC; M. obtusa (Muhl.) Vail] 



D. ciliarc (Muhl.) DC. 



