350 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Specimens examined: ChehalisCouniy, Lami 1197; Walla Walla, Z^ci-eniy, Juno, 1898; 

 Blue Mountains, Piper, July, 189G: Palouse City, Afoore, June, 1893; Hendenon, July, 1892. 

 Zonal distribition: Arid Transition. 

 The type is Piper 1489, collected on Cedar Mountain, Latah County, Idaho. 



PETALOSTEMTJM. 



1. Petalostemum omatum Dougl.; Hook. Fl. Bor. Am. 1: 138. 1830. 



Type localiti' : "' Frwjuent in the arid prairie.s near the Blue Mountains of Lewis [Snake] 

 River, North-West America." Collected by Douglas. 

 . Ra.nt.e: Eastern Wa-shington, eastern Oregon, and south Idaho. 



Specimens examined: Pasco, Pifter 2973; Leckenby in June, ^898; Walla Walla, Lyall 

 in 1860; near Columbia and Snake rivers, Brandegee 714. 



Zonal distribltion: Upper Sonoran. 



LUPINTJS. LtPiNE. 



Subgen. I. PL.\TYCARPOS S. Wats.— Ovary 2-ovuled, forming a 

 short and relatively broad 2-(l-)s<>eded pod; annuals or biennials 

 with deep often lignesoent taproot and persisting cotyledons. 



Peduncles 1 to 2 cm. long; flowers small; corolla about 1 cm. long 1. L. ptisiUus. 



Peduncles 5 to 15 cm. long; flowers larger; corolla 1.5 cm. long 2. L. microcarpus. 



Sul)gen. II. Ll'PINl'S proper. — Ovarj' 3 to many-ovuled, forming an 



oblong to linear several-seeded pod ; cotyledons not persisting.« 

 } 1. Micranthi. — Annuals, slender, branching from the base; leaflets 



glabrous on the upper surface. 

 Flowers subscssile: wings oblong, 6 mm. in length; corolla usually 



pale purple ; 3. L. micranthus. 



Pedicels 4 mm. long; corolla deep blue; wings 8 mm. long 4. L. hicolor. 



§2. Sericei. — Perennials; calyx subsymmetrical at the base; corolla 

 blue, varj'ing to white or roseate; keel usually ciliate; leaflets 

 appres.sed-pubescent and silky (rarely tomentose) on both sur- 

 faces, canescent. 

 Stems scapose or subscapose, 7 to 25 (rarely 40) cm. high; leaves 

 chiefly ba.sal; flowers sessile or on very short pedicels. 

 Very dwarf (7 to 15, rarely 20, cm. high), cespitose; flowers subscs- 

 sile, small; keel 6 to 8 mm. long. 



Leaflets 5 to 8, very small, 6 to 10 mm. long 5. L. lyallii. 



Leaflets 7 to 12, at least 12 to 20 mm. long. 



DeiLsely and somewhat shaggy sericeous-pubescent; vexillum 



obovate-oblong 6. L. aridus. 



Covered with a fine and closely appressed sericeous pubescence; 



vexillum suborbicular 7. L. minimus. 



oThe following key will aid in locating a species in its proper section: 



Annuals, branching from the ba.se; flowers small 1. Micrantiii. 



Perennials. 



Calyx saccate or spurred at the base 6. Calcarati. 



Calyx symmetrical or nearly so at base. 



Flowers yellow , 5. Sulphurei. 



Flowers purple or violet. 



Leaves green, the pubescence thin, never silky or villous 4. Rivulares. 



Leaves sericeous or villous. 



Pubescence sericeous 5. Sericei. 



Pubescence villous 6. Saxosi. 



