454 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



flowering, and a number of them contribute to the forage value of the 

 stock ranges. The Indians of southwestern Arizona formerly dyed 

 basket material with an extract from the glandular twigs of Dalea 

 emoryi. The Hopi ate the roots of D. terminalis as a sweet. D. 

 scoparia has been suggested for use in control of soil erosion. 



Key to the species 



1. Petals inserted on the hypanthium at base of the staminal tube; plants shrubby 



or arborescent (2) . 



2. Leaves unifoliolate, exceptionally 3-foliolate, in one species fugacious (3). 



3. Calyx externally glabrous or nearly so, shining, the glands in each interval 



between the ribs small, as many as 4 or sometimes wanting; flowers 



indigo, not crowded, racemose; arborescent shrub with spinescent 



branches and persistent, linear leaves 3. I), schottii. 



3. Calyx pubescent (4). 



4. Calyx strigose-canescent, with 1 large gland in each interval between 

 the ribs; leaves fugacious; flowers indigo, racemose, not crowded; 



arborescent, the branches spiny 4. D. spinosa. 



4. Calyx villous, with 2 to 4 glands in each interval; leaves persistent, 

 spatulate-linear or oblanceolate, exceptionally 3-foliolate; flowers 

 dark blue, crowded in subglobose or ovoid-cylindric spikes 12 to 15 

 mm. thick; unarmed shrub 0.5 to 2 m. high, the branches and pe- 

 duncles finely retrorse-strigose 7. D. scoparia. 



2. Leaves several-foliolate; plants shrubby or arborescent, commonly more or 



less spinescent (5) . 



5. Branches when young retrorsely hairy and conspicuously punctate with 



orange-colored glands, spinescent; leaflets 2 to 4 mm. long; calyx lobes 



shorter than the tube; corolla pink or purple (6). 



6. Calyx glabrous externally, the ribs rather prominent, the lobes ciliate, 



the upper ones obtuse or rounded, the lowest lobe acute; leaflets 



5 to 9, elliptic or slightly obovate 8. D. thompsonae. 



6. Calyx copiously pubescent externally, the ribs not prominent (7). 

 7. Racemes dense; calyx lobes acute, lance-subulate; leaflets 7 to 13, 



orbicular to oblanceolate 5. D. polyadenia. 



7. Racemes lax, few-flowered; calyx lobes obtuse or rounded, the upper 

 ones nearly as wide as long; leaflets 11 to 19, oblong to oblanceo- 

 late 9. D. WHITINGI. 



5. Branches not retrorsely hairy; leaflets 4 to 15 mm. long (8). 



8. Branches velutinous-canescent, unarmed; flowers purple, in capitate 

 spikes; shrub about 1 m. high; leaflets 1 to 13, more or less serrate, 

 the terminal one 10 to 25 mm. long, usually 2 or 3 times longer than 



the lateral leaflets 6. D. emoryi. 



8. Branches strigose, often canescent but not velutinous; flowers indigo (9) . 

 9. Calyx lobes dissimilar (the upper ones broader) , deltoid to triangular- 

 lanceolate, usually shorter than the tube 1. D. FREMONTII. 



9. Calyx lobes all alike, lance-subulate, equaling the tube. 



2. D. AMOENA. 



1. Petals (the paired ones) manifestly inserted on the staminal tube, the scars 

 plainly visible on the tube after the petals fall away (10). 

 10. Flowers evidently pediceled, but often very shortly so (11). 

 11. Calyx lobes foliaceous; stems not conspicuously glandular (12). 



12. Stems prostrate or nearly so, entirely herbaceous; calyx densely pilose, 

 the lobes lanceolate, nearly twice as long as the tube; leaflets 15 to 29; 



flowers purple and white 10. D. calycosa. 



12. Stems strongly ascending or erect, often somewhat suffrutescent (13). 

 13. Stems, leaves, and calyx glabrous; calyx lobes ovate, obtuse, shorter 

 than the tube; leaflets of the stem leaves 13 to 23, those of the 

 branches 3 to 9; paired petals purple, the banner yellowish. 



11. D. DIFFUSA. 



13. Stems, leaves, and calyx strigose-canescent; calyx lobes triangular, 

 acute, shorter than or equaling the tube; leaflets 15 to 33; flowers 

 purple and white 12. D. parryi. 



11. Calyx lobes setaceous from a deltoid base (14). 



14. Plant annual; stem erect, branching above the middle, sparsely glandu- 

 lar, glabrous; staminal tube long-exserted 16. D. lagopus, 



