FLOWERING PLANTS AND FERNS OF ARIZONA 421 



Indians in much the same way. Livestock browse on the leaves 



and the pods. The bark of the roots was used by the Pima Indians 

 to treat wounds. Fence posts and handles for tools are obtained 

 locally from the screwbean. 



2. < .' \! ■:> LLPINIOIDE IlE. SENNA SUBFAMILY 



Key to the genera 



1. Corolla pink or purple; leaves simple, entire (2). 



2. Fruits indehiscent, turgid, globose or ovoid, spiny: plants small straggling 

 shrubs or perennial herbs: leaf blades small, linear or narrowly lanceolate; 

 flowers borne on the branchlets 7. Krameria. 



2. Fruits dehiscent, flat, oblong, not spiny: plant a large shrub or small tree; 



leaf blades large, round-cordate: flowers borne on the old wood. 



8. Cercis. 

 1. Corolla yellow: leaves compound (3). 



3. Leaves once-pinnate: plants herbaceous or shrubby 9. Cassia. 



3. Leaves twice-pinnate, sometimes appearing simply pinnate in Parkinsonia 



because of the shortening of the primary rachis (4). 

 4. Filaments 3 or 4 times as long as the petals, bright red, very conspicuous; 

 plant a shrub; pods 5 cm. long or longer, broad, very flat. 



13. Caesalpixia. 

 4. Filaments not or but slightly surpassing the petals (5). 



5. Plants unarmed, herbaceous or somewhat woody: pods not torulose. 



12. HoFFMAXSEGGIA. 



5. Plants spiny, large shrubs or small trees; pods often torulose; young 

 bark green (6). 

 6. Rachis of the pinnae flattened, 10 cm. long or longer; leaflets alternate; 

 inflorescence an elongate raceme up to 20 cm. long; calyx lobes 



strongly imbricate in bud 10. Parkixsoxia. 



6. Rachis of the pinnae terete, not more than 4 cm. long; leaflets opposite; 

 inflorescence a short raceme or a corymb; calyx lobes valvate or 

 induplicate-valvate in bud 11. Cercidium. 



7. KRAMERIA. Rataxt 



Straggling low shrubs or perennial herbs, the herbage grayish 

 pubescent and sometimes glandular; leaves alternate, simple, without 

 stipules; flowers very irregular, rather showy, purplish, in racemes, 

 or solitary and axillary; petals 5, smaller than the sepals, the upper 3 

 petals long-clawed, the others reduced to nearly orbicular fleshy 

 glands; stamens 3 or 4, more or less united; pod globose or nearly so, 

 indehiscent, thick-walled, spiny, 1 -seeded. 



These plants, sometimes called chacate, are supposed to be root 

 parasites. With the exception, perhaps, of K. lanceolate they are 

 relished by livestock. K. grayi, sometimes called erimsonbeak, is 

 very drought resistant. The common name ratany is sometimes 

 applied to native species on account of their relationship with the 

 South American species from which the powerfully astringent rhatany 

 root of commerce is obtained. The Papago Indians treat sore eyes 

 with an infusion of the twigs of K. parvifolia, and a dye, used to color 

 wool and other materials, is obtained from the roots. All of the species 

 grow on dry plains and mesas. They are peculiar in this family in the 

 structure of the flowers and fruits. 



Key to tht sp, cii s 



1. Stems herbaceous above ground from a thick woody caudex. prostrate or nearly 

 so, the leaves and flowers more or less secund; upper petals with broad 

 "blades, more or less united below; spines of the fruit not barbed; glands 

 none 1- K. lanceolata. 



