266 



LEPTOCARPI. 28. 



Weak annuals. Flowers rarely 1 cm. long, mostly 

 very small, in heads (rarely in few-flowered racemes). 

 Pods papery, not inflated, linear (narrowly oblong in A. 

 Wrightii) and falcate below (straight in A. Wrightii 

 and nearly so in A. leptocarpus), sulcate dorsally, sharply 

 acute (obtuse in A. Francisquitensis) , sessile (stipitate 

 in A. Lindheimeri), mostly horizontal (nearly erect in 

 A. Wrightii), never closely reflexed, 2-celled (partition 

 rarely incomplete). Stipules not connate. 



KEY. 



A. Flowers few and racemose at least in fruit, with blunt or barely- 

 acute keel not at all produced, purple-tipped; peduncles filiform. 

 Pods smooth. Plants of the Tropical life zone (A. Nuttallianus 

 extends also into the Lower Temperate life zone), nearly smooth 

 throughout when mature. 

 AB. Pods about 1 cm. long, nearly smooth. 



Very slender plants. 234 Francisquitensis. 



A2B. Pods at least 2.5 cm. long, arched most below when curved, 

 mostly more than 2 mm. high, narrowed at both ends, and ap- 

 parently stipitate in A. Lindheimeri. Flowers 1-1.5 cm. 

 long. Banner deeply notched, white spot large and purple- 

 veined, wings white. Peduncles axillary and long. Leaflets 

 7-8 pairs, broadly elliptical to obovate, notched, thin. Bracts 

 subulate. Stems not conspicuously sulcate, growing in dense 

 vegetation and seemingly erect but weak and sprawling when 

 not supported. Plants of the southeastern part of the great 

 plains, nearly smooth when mature. 



Pods 5nini. high. 235 Lindheimeri. 



Pods 2 mm. liigh. 236 leptocar]ius. 



2A. Flowers in heads, purple or purple-tipped. Keel not acuminate 

 nor sharp. Pods equally arched or nearly straight, 1.5-4 cm. 

 long, linear or nearly so. Peduncles filiform, not over 5 cm. 

 long, axillary. Plants slender but mostly erect. 

 2AB. Plants of the Californian plains. Pods not shaggy, on 

 reflexed pedicels but with tips often erect, stipitate or ta- 

 pering at base, nearly smooth at maturity, taper-pointed, not 

 fully 2-celled, dorsally sulcate, nearly circular to reniform 

 in cross-section, inclined to be obcompressed. Flowers 7-12 

 mm. long. Calyx tube about 2 mm. long, campanulate, ni- 

 grescent, reflexed to horizontal in fruit, with teeth triangular 

 to subulate and rather shorter than the tube. Bracts and 

 pedicels short. Heads of flowers not elongating in fruit. Pet- 

 ioles all evident except on the uppermost leaves. Stems }z 

 to 2 feet high, rather widely branched below. 



Pods 1-2 cm. kfng. 237 tener. 



Pods 3-4 cm. lont. 238 Ratlani. 



2A2B. Plants of the Texan plains. Pods shaggy, straight, erect, 

 or only spreading about 1 cm. long, broadly linear to nar- 

 rowly-oblong. Calyx tube very short and lobes very long and 

 green. Whole plant appressed-shaggy. 



Pods in heads. " 239 Wrightii. 



