164 American Midland Naturalist Monograph No. 2 



2. Leaflets ovate, acuminate; pods 1 cm. long; stem 1-1.5 m. tall; river banks, 



not common. June-July. [^Orbexilum onobrychis (Nutt.) Rydb.} 



P. onobrychis Nutt. 



2. Leaflets elliptical; pods 4 mm. long; stem 30-60 cm. tall; wooded ridges 

 and slopes, s. 111., not common. June-July. [Orbexilum pedunctilatum 

 (Mill.) Rydb.} The plants of the Central States are less glandular 

 and have been named P. psoralioides var. eglandulosa (Ell.) F. L. 



Freeman P. psoralioides (Walt.) Cory 



1. Leaves digitately 3-5-foliolate; leaflets oblanceolate; pods about 8 mm. long, 

 not rugose-reticulate; dry soil, not common; McHenry, Kane, Cook, 

 Will, and Peoria counties. June-Oct. [Psoraliditwi floribundum (Nutt.) 

 Rydb.; P. floribunda Nutt.} P. tenuiflora Pursh 



16. Amorpha L. 



1. Leaflets 2-5 cm. long; shrubs 1.5-6 m. tall; pods usually 2-seeded, 6-8 mm. 



long; river banks and alluvial soil, locally throughout 111. May-June. 



False Indigo A. fruticosa L. 



1. Leaflets 9-18 mm. long; densely canescent shrubs less than 1 m. tall; pods 



1 -seeded, 3-4 mm. long; prairie soil and hillsides, locally throughout 111., 



except the s. counties. June-July. Lead-plant A. canescens Pursh 



17. Dalea Juss. 



D. alopecuroides Willd. Fields and roadsides, occasional. Aug. -Sept. 

 [Parosela dalea (L.) Britt.} 



18. Petalostemum Michx. — Prairie-clover 



1. Calyx-tube densely silky-velutinous; leaflets 3-9; corolla rose-purple, rarely 

 white; in sandy or gravelly soil along roads or in open woods, local. July- 



Aug. Purple Prairie-clover P. purpureutn (Vent.) Rydb. 



1. Calyx-tube glabrous. 



2. Leaflets 5-9; flowers white; in habitats similar to the preceding species, but 



of less frequent occurrence. June-Aug. White Prairie-clover 



P. candidum (Willd.) Michx. 



2. Leaflets 13-31; flowers rose-purple; river banks and gravelly soil, rare; Kan- 

 kakee Co., Hdl; Kane Co., G. D. F idler. July-Sept P. joliosum Gray 



19. Tephrosia Pars. 



{Cracca L.) 

 T. virginiana (L.) Pers. Goat's-rue. Dry sandy soil. June-July. 



20. RoBiNiA L. — Locust 



l.Tree 5-30 m. tall; twigs and petioles glabrous; flowers white, in pendulous 

 racemes; pods glabrous; commonly cult., and abundantly naturalized 



throughout 111.; native of e. U.S. May-June. Common Locust 



R. pseudo-acacia L. 



1. Shrub 0.3-3 m. tall; twigs and usually the petioles glandular-hispid; flowers 

 rose-purple, in erect racemes; pods hispid; cult., and occasionally spont.; 



native of the mts. of Va. and Ga. May-June. Bristly Locust 



_ R. hispida L. 



