896 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



1. Vanclevea stylosa (Eastw.) Greene, Pittonia 4: 51. 1899. 



Grindelia stylosa Eastw., Calif. Acad. Sci. Proc. ser. 2, 6: 293. 

 1896. 

 Monument Valley, Navajo County, 5,000 to 6,000 feet, September 

 (Eastwood and Howell 6660) , also reported by Aven Nelson from Red 

 Lake, eastern Coconino County. Southeastern Utah and north- 

 eastern Arizona. 



12. GUTIERREZIA. Snakeweed 



Perennial herbs, sometimes suffrutescent, more or less glutinous; 

 leaves alternate, linear to narrowly oblanceolate, entire; heads small, 

 yellow, radiate, usually numerous and crowded; involucre cylindric to 

 campanulate, the phyllaries chartaceous, scarious-margined, with 

 small green tips; achenes small, oblong or obovoid; pappus of several 

 squamellae or paleae, often shorter iri the ray flowers. 



Also known as matchweed, resinweed, broomweed, turpentine- 

 weed. Plants of dry stony plains, mesas, and slopes. The snake- 

 weeds are worthless plants that are not even of much value in retard- 

 ing soil erosion. They are more or less poisonous to sheep and 

 goats when eaten in quantity but are unpalatable and are seldom 

 grazed. The carrying capacity of much southwestern grassland has 

 been greatly reduced by encroachment of the snakeweeds. 



Key to the species 



1. Heads tiny, cylindric, about 1 mm. thick; rays 1 or 2; disk flowers 1 to 3 (2). 

 2. Heads sessile, in fasciculate glomerules of 2 to 5; ray 1 (very rarely 2); disk 

 flowers 1 or 2 1. G. lucida. 



2. Heads often pedicelled, not fasciculate-glomerulate; rays 2; disk flowers 2 or 



3 2. G. LINOIDES. 



1. Heads larger, slender-turbinate to subglobose; rays 3 to 12; disk flowers 1 to 12 

 (3). 



3. Heads subglobose to broadly turbinate; ray flowers 7 to 14; disk flowers 7 



to 24 3. G. CALIFORNICA. 



3. Heads turbinate; flowers of the rays and the disk each 3 to 8, or the disk 

 flowers rarely only 1 or 2 (4) . 

 4. Involucre very slenderly turbinate, 1 to 1.5 mm. thick; rays 4 or 5; disk 



flowers 1 to 3 4. G. microcephala. 



4. Involucre turbinate, usually 2 mm. thick or more; rays 3 to 8; disk flowers 

 3 to 8 5. G. sarothrae. 



1. Gutierrezia lucida Greene, Fl. Francisc. 361. 1897. 



Xanthocephalum lucidum Greene, Pittonia 2: 282. 1892. 

 Gutierrezia glomerella Greene, Pittonia 4: 54. 1899. 



Almost throughout the State, 1,200 to 6,000 feet, June to October. 

 Colorado to Texas, west to Nevada and California, south to Mexico. 



2. Gutierrezia linoides Greene, Leaflets 2: 22. 1909. 



Definitely known only from the Chiricahua Mountains, Cochise 

 County (Blumer in 1907, the type). The status of this species is not 

 clear. 



3. Gutierrezia californica (DC.) Torr. and Gray, Fl. North Amer. 2: 



193. 1842. 

 Brachyris californica DC, Prodr. 5: 313. 1836. 

 Gutierrezia serotina Greene, Pittonia 4: 57. 1899. 

 Gutierrezia polyantha A. Nels., Amer. Jour. Bot. 25: 117. 

 1938. 

 Yavapai, Pinal, Cochise, and Pima Counties, 1,200 to 4,200 feet, 

 March to October, type of G. serotina from Tucson (Tourney in 1892), 



