138 FAB ACE AE 



Calyx-lobes shorter than the tube, the upper two much broader than the rest. 

 Leaflets 1-7, oblong or elliptic. 1. P. Fremontii. 



Leaflets 5-11, linear or linear-oblanceolate. 2. P. Johnsoni. 



Calyx-lobes equalling the tube, all lanceolate, nearly similar. 3. P. amoena. 



Wing- and keel-petals adnate to or inserted on the staminal tube, some distance from the 

 base; pod shorter than the calyx; mostly herbs, rarely shrubs (Eudalea). 

 Stem and leaves glabroxis. 



Annual; spike den.se, cyUndric. 4. P. alopecuroides. 



Perennial; spike either rather lax or few-flowered. 



Plant herbaceous: spike lax, elongate, several-flowered; bracts obovate, per- 

 sistent, enclosing the calyx. 5. P. enneandra. 

 Plant shrubby; spike head-like, 2-10-flowered, very short; bracts ovate, de- 

 ciduous. 6. P. formosa. 

 Stem and leaves pubescent. 



Calyx-lobes short, ovate, not subulate-tipped; spike lax; prostrate or decumbent 



villous herbs. 7. P. lanata. 



Calyx-lobes subulate-tipped, longer tlian the tube; plants erect or decimibent, 

 with a short cespitose caudex; spike dense. 

 Leaves 3-foliolate. 8. P. Jamesii. 



Leaves 5-foliolate. 



Stem low, 1-2 dm. liigh, decumbent at the base; spike sessile or short- 



peduncled. 9. P. carnescens. 



Stem tall, 3-5 dm. high, with the upper leaves reduced and spike rather 

 long-pedtmcled. 10. P. aurea. 



15. PETALOSTEMON Michx. Prairie Clover. 



Calyx glabrous except the teeth; corolla white. 



Spikes compact; bracts longer than the buds; leaflets 1.5-2.5 cm. long. 



1. P. candidus. 

 Spikes looser; bracts shorter than the buds; leaflets usually less than 1.5 cm. long. 



2. P. oligophyllus. 

 Calvx pubescent. 



Corolla white or yellow; spike long and compact. 



Leaves glabrous ; corolla white or ochroleucous. 3. P. compactus. 



Leaves sparingly silky; corolla yellow. 4. P. flavescens. 



Corolla rose or purple, very rarely white. 

 Leaflets mostly 5, linear or nearly so. 



Pubescence of the calyx long silky-pilose; bracts lanceolate, acute; leaflets of 

 the lower leaves oblong, obovate, or cuneate. 

 Bracts glabrous or short-pilose. 5. P. Searlsiae. 



Bracts silky, long-pilose. 6. P. ornatus. 



Pubescence of the calyx dense and short; bracts ovate, villous, with a long 

 subulate glabrous acumination. 

 Leaflets linear, conspicuously glandular-dotted; bracts longer than the 

 calyces. 

 Stem and leaves glabrotis or sparingly hairy. 7. P. purpureus. 



Stem and leaves densely \-illous. 8. P. mollis. 



Leaflets spatulate-linear, not glandular-dotted; bracts shorter than the 

 calyces. 9. P. pubcscens. 



Leaflets 7-17, oblong. 10. P. villosus. 



16. ROBINIA L. Locust-tree. 



Inflorescence, leaves and fruit glabrous. 1. R. Pseudacacia. 



Inflorescence and fruit hispid; leaves flnely puberulent. 2. R. neomexicana. 



17. PETERIA A. Gray. 



Leaflets linear-elliptic or lanceolate, acute and mucronate, 2-6 mm. long, or wanting ; 



corolla 12-15 mm. long. , , . . 1. P. scopana. 



Leaflets broadly elliptic, oval, or obovate, rounded and mucronate at the apex, 8-15 



mm. long. 2. P. Thompsonae. 



18. PHACA L. Rattle-weed, Rattle-pod. 



Upper suture of the pod not acute ; pod circular or oval in cross-section. 

 Pod stipitate. , , . , ^, ^, 



Pod long-stipitate, not mottled; stipe longer than the calyx. 



Pod pendent; flowers ochroleucous. 1. P. americana. 



Pod on an ascending stipe; flowers purplish. 2. P. ampularia. 



Pod short-stipitate; stipe scarcely exceeding the calyx. 

 Pod not mottled, erect or ascending. 

 Pod ashv-strigose, with minute hairs. 



Pods silicate above; leaflets broad. 3. P. Wetnenlhi. 



Pod not sulcate; leaflets narrow. 4. P. allochroa. 



Pod glabrous. 



Flowers purplish; racemes long-pedimcled ; pods about 2 cm. long. 



5. P. Eastwoodiae. 

 Flowers white; racemes short-peduncled ; pods 3-4 cm. long. 



6. P. lulosa. 

 Pod mottled, spreading or reflexed. 



Leaflets linear or none; plant grayish pubescent. , . , ^ , 



Terminal leaflet none, represented by the much produced rachis ; lateral 

 leaflets often also lacking. 7. P. longifoha. 



