964 MISC. PUBLICATION 423, U. S. DEPT. OF AGRICULTURE 



2. Thelesperma subnudum A. Gray, Amer. Acad. Arts and Sci. Proc. 



10: 72. 1874. 



Apache County to eastern Coconino County, 5,000 to 6,200 feet, 

 dry hills and stream banks, May to August. Colorado and Utah to 

 northern New Mexico and northeastern Arizona. 



Sometimes known as Navajo-tea. 



3. Thelesperma longipes A. Gray, PL Wright. 1: 109. 1852. 

 Chiricahua, Mustang, and Santa Catalina Mountains (Cochise, 



Santa Cruz, and Pima Counties), 5,000 to 6,000 feet, slopes and can- 

 yons, often on limestone, June to September. Western Texas to 

 southeastern Arizona and northern Mexico. 



Used as a substitute for tea in New Mexico, under the name cota. 



Thelesperma simplici folium A. Gray (T. subsimplicifolium A. Gray) is reported 

 to occur in Arizona but has not been seen by the writer from west of Texas. 



75. BIDENS. 89 Spanish-needles 



Annual or perennial herbs; leaves, at least the lower ones, opposite, 

 entire to dissected; heads medium-sized to large, often showy, usually 

 radiate and yellow, sometimes discoid or with white rays; involucre 

 double as in Coreopsis; achenes linear-fusiform or linear to cuneate, 

 more or less tetragonal or dorso-ventrally compressed; pappus of 2 

 to 4 retrorsely hispid awns, rarely wanting. 



These plants are known also as bur-marigold, sticktight, pitch- 

 forks, beggarticks, and watermarigold, most of these names referring 

 to the tendency of the awned fruits to adhere to clothing and the hair 

 of animals. 



Key to the species 



1. Leaves sessile, serrate or serrulate, not lobed, lanceolate or lance-oblong; achenes 

 narrowly cuneate, retrorse-hispidulous on the margin; rays 1.5 to 3 cm. 



long, bright yellow 1. B. laevis. 



1. Leaves petioled, pinnately or bipinnately divided (except in B. aurea) ; achenes 



linear or linear-fusiform, antrorsely pilose or hispidulous on the margin, 



or glabrous; rays usually smaller (2). 



2. Achenes not conspicuously elongate, usually little exceeding the involucre; 



inner phyllaries with conspicuous yellow margins half as wide as the 



brown center, or wider; rays yellow, conspicuous, 1 cm. long or longer (3). 



3. Leaves twice or thrice pinnatisect, the lobes narrowly linear, not more 



than 2 mm. wide 9. B. ferulaefolia. 



3. Leaves lanceolate or oblong, serrate and not lobed, or pinnately parted 



into 3 or 5 lanceolate or linear divisions at least 6 mm. wide. 



10. B. AUREA. 

 2. Achenes (at least the inner ones) conspicuously elongate (least so in B. pilosa) , 

 usually (including the awns) twice as long as the inner phyllaries; inner 

 phyllaries with inconspicuous pale margins; rays wanting or inconspic- 

 uous, or if conspicuous, then white (4). 



4. Leaves all pinnately 3- or 5-parted, with lance-oblong to rhombic-ovate, 



serrate to incised divisions 2. B. pilosa. 



4. Leaves all once or twice pinnately dissected (5) . 



5. Outer and inner phyllaries more or less densely pilose or hirsute; heads 

 campanulate; leaves 2 or 3 times dissected, into linear lobes. 



5. B. TENUISECTA. 



5. Outer and inner phyllaries merely short-ciliate, rarely sparsely pilose (6). 

 6. Heads (when normally developed) campanulate, more than 13-flow- 

 ered (7). 



86 Reference: Sherff, E. E. the genus bidens. Field Museum Nat. Hist. Bot. Ser. ]6: 1-709. 1937 



