54. Leguminosae 133 



15. Hosackia Dougl. 

 H. mnericana (Nutt.) Piper. Dry soil, rare; adv-. from the West; 

 Cook Co., W. S. Moffatt in 189.'^; Greene Co.. F. E. McDonald in 

 1904. June-Aug. 



16. Psoralea L. — Scurf-pea 



1. Leaves pinnately 1- to 3-foliolate; pods rugose-reticulate. 



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

 ri\'er banks, not common. June-July. [Orbexihun onobrychis 



(Nutt.) Rydb.] P. onobrychis Nutt. 



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

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



pcdunculatum (Mill.) Rydb.] P. psoralioides (Walt.) Cory 



1. Leaves digitately 3- to 5-foliolate ; leaflets oblanceolate ; jxjds 

 about 8 mm long, not rugose-reticulate; dry soil, locally in 

 northern 111., extending southward to Madison and Monroe 

 counties. June-Oct. [P. florihunda Nutt.] P. tenuiflora Pursh 



17. Amorpha L. 

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

 6-8 mm long. 

 2. Leaves dull above; petiohdes pubescent; river banks and allu- 

 vial soil, locally throughout 111. May-June. Indigo Bush 



A. fruticosa L. 



2. Leaves glossy above; petiolules glabrous; along rivers, rare; 



Pope Co. May-June A. nkens Boynton 



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 



nearly throughout 111. June-July. Lead-plant 



A. canescens Pursh 



18. Dalea Juss. 

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

 Sept. [Parosela dalea (L.) Britt.]. 



19. 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. purpureum (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-clov-er P. candidum (Willd.) Michx. 



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



rare, or probably now extinct in 111. July-Sept 



P. foliosum A.Gray 



