884 MISC. PUBLICATION 4 2 3, IT. S. DEPT. OF AGRICULTURE 



Key to the species 



1. Annual; leaves membranaceous, ovate, more than half as wide as long, serrate; 

 pappus of 3 awns and 3 very short intermediate squamellae; heads rather 



loosely cymose; corollas whitish 1. S. micrantha. 



1 Perennial; leaves usually firm, linear to elliptic, much less than half as wide as 

 long (2). 

 2. Heads definitely pedicellate, loosely cymose-panicled; corollas purple; leaves 



alternate, linear, entire or bluntly toothed 2. S. viscida. 



2. Heads subsessile, in dense fastigiate cymose panicles; corollas white or rose 

 color (3). 

 3. Leaves entire, linear-elliptic or lanceolate, opposite, 3-nerved but not 

 strongly veiny; plant suffrutescent or shrubby; pappus a very short, 



toothed crown 3. S. lemmoni. 



3. Leaves serrate, linear to lance-oblong or oblong, often alternate or veiny; 

 plants herbaceous (4) . 

 4. Leaves mostly opposite, not very numerous, strongly veiny beneath, 

 elliptic to elliptic-oblong or lance-oblong, the larger leaves 10 to 



18 mm. wide; pappus of squamellae only 4. S. plummerae. 



4. Leaves mostly alternate, usually very numerous and crowded, narrowly 

 linear-oblanceolate to spatulate-oblanceolate, cuneate, or oval, 3 to 

 10 (rarely 15) mm. wide; pappus normally of awns and squamellae. 



5. S. serrata. 



1. Stevia micrantha Lag., Gen. et Sp. PI. 27. 1816. 



Sterna macella A. Gray, PL Wright. 2: 70. 1853. 



Chiricahua and Huachuca Mountains (Cochise County), Santa 

 Rita and Baboquivari Mountains (Pima County), 5,000 to 6,500 feet, 

 rich moist soil in canyons, August to October. Southwestern New 

 Mexico, southern Arizona, and Mexico. 



2. Stevia viscida H. B. K., Nov. Gen. et Sp. 4: 140. 1820. 



Stevia amabilis Lemmon ex A. Gray, Amer. Acad. Arts and 

 Sci. Proc. 19: 1. 1883. 



Plains near the Huachuca Mountains, Cochise County {Lemmon 

 2729, the type of S. amabilis), September. Southeastern Arizona 

 and Mexico. 



3. Stevia lemmoni A. Gray, Amer. Acad. Arts and Sci. Proc. 17:204. 



1882. 

 Oro Blanco Mountains (Santa Cruz County) , Santa Catalina Moun- 

 tains (Pima County), rocky canyons, April, type from the Santa 

 Catalina Mountains (Lemmon). Southern Arizona and northern 

 Mexico. 



4. Stevia plummerae A. Gray, Amer. Acad. Arts and Sci. Proc. 17: 



204. 1882. 



White Mountains (Apache County), Chiricahua and Huachuca 

 Mountains (Cochise County) , Santa Catalina and Santa Rita Moun- 

 tains (Pima County), 6,000 to 7,600 feet, rich soil in canyons, April to 

 October, type from Rucker Valley, Chiricahua Mountains (Mrs. 

 Lemmon). New Mexico, Arizona, and northern Mexico. 



The flowers are fragrant. The var. alba A. Gray is a form with 

 white flowers. 



5. Stevia serrata Cav., Icon. PL 4: 33. 1797. 



Mountains of southern Apache, Graham, Cochise, Santa Cruz, 

 and Pima Counties, 4,500 to 9,000 feet, chiefly in pine forest, April to 



