KEY TO THE SPECIES 8Y 



1. Balsamorrhiza eagittata Nutt. (Arrow-leaved Balsam-root). Koot 

 large, woody, vertical, often 1 m. in length ; leaves crowded on the crown, cordate- 

 oblong to sagittate, 1-2 dm. long, on longer petioles, silvery-canescent ; scape 

 equaling or surpassing the leaves ; heads 8-10 cm. broad. Moist rocky ravines 

 and slopes. 



9. TETRANEURIS 



Low perennials, the following csespitose, with crowded narrow radical leaves 

 and scapose monocephalous stems, involucre of nearly equal bracts, conspicuous 

 yellow 4-nerved (whence the name) rays, and silky-villous achenes. 



1. Tetraneuris acaulis (Pursh) Greene (Stemless Tetbaneuris). Silvery 

 silky-pubescent ; cffispitose, often in broad mats ; leaves crowded on the crowns 

 of the branched caudex, spatulate-linear, much exceeded by the 7-12-cm.-long 

 scapes ; heads 20-25 mm. broad ; involucre somewhat woolly; rays 10-15 ; pappus 

 of few awned scales. Dry rocky soil. ^ 



2. Tetraneuris acaulis caespitosa Aven Nelson, More depressed, inordi- 

 nately, silky-villous throughout ; heads su.aller and scarcely rising above the leaves 

 of the broad mat. Sandy-clay draws and ravines. 



3. Tetraneuris simplex Aven Nelson (Simple Tetraneuris). Appressed 

 pubescent ; plants singly, rarely in small tufts ; caudex short, of 1 or more crowns 

 on a vertical tap-root ; leaves linear-spatulate ; scapes singly from the crown, 15-25 

 cm. high ; heads large, 2.5-4 cm. broad, silky-lanate on the involucre. Sandy 

 valleys and plains. 



4. Tetraneuris Torrej ana (Nutt.) Greene (Torrey's Tetraneuris). Strongly 

 caespitose-tufted ; the numerous branches of the caudex thick and inordinately 

 clothed by the imbricated bases of the leaves of the previous years, these involved 

 in a dense hirsute-wool ; leaves nearly glabrous, bright green, closely and, con- 

 spicuously resinous impressed-punctate, linear, 4-7 cm. long, somewhat exceeded 

 by the hghtly woolly scapes ; heads large, 3-5 cm. broad, deep yellow, the rays 

 persistent and becoming white and membranous in age. Stony ridges and bluffs. 



10. GAILLARDIA 



Erect herbs with alternate leaves and large showy mostly long-peduncled 

 flowers, yellow rays and yellow disk turning brownish, and the villous achenes 

 with slender-awned pappus scales. 



1. Gaillardia aristata Pursh (Great-flowered Gaillardia). Somewhat 

 hirsute, the hairs jointed ; stems erect, 3-6 dm. high ; leaves spatulate to lanceo- 

 late, entire, sinuate-dentate or even laciniate ; heads 6-10 cm. broad ; bracts of 

 the involucre lanceolate, acuminate. Frequent on sandy plains and slopes. 



11. STENOTUS 



Densely caespitosa perennials with woody base, narrow entire leaves, scapose 

 stems, large heads of yellow flowers, campanulate involucre, alveolate receptacle, 

 villous achenes with a pappus of white capillary bristles. 



1. Stenotus armerioides Nutt. (Narrow-leaved Stenotus). Glabrous ; 

 leaves rigid, crowded on the crowns, narrowly spatulate-linear, acute ; stems 

 about twice as long as the leaves, S-3-leaved, naked-pedunculate above ; bracts of 

 the involucre oblong, obtuse, scarious margined. Dry naked banks and hills. 



