236 



American Midland Naturalist MoNOGRAt-H No. 4 



spines; flowers yellow, borne in heads of about 5 surrounded by an involucre 

 of 5 bracts; bracts about 1/3 inch long, smooth; seed-like fruits (achenes) 

 densely hairy, but the hairs much shorter than the tuft of long hair-like 

 bristles (pappus) at the tip; heads borne singly in the axils of the leaves. 

 Occurrence. — ZION : hill at mouth of Coalpits Wash, 4,000 feet. 



Snakeweed (Gutierrezia Lag.) 

 Field Guide to the Species 



Bushes broom-like; stems densely leafy, the leaves somewhat sticky; ray and disk 



flowers 3 1o 7 each I. C. saroihrae. 



Stems straggling, more sparsely leafy, the leaves very sticky; ray and disk flowers I 



or 2 each 2. C. lucida. 



1. Broom Snakeweed 

 {Gutierrezia sarothrae Britt. & 

 Rusby), fig. 142. — Low bushy 

 plant, 1 to 2 feet high, with nu- 

 merous erect stems from a woody 

 base; leaves linear, 1 to 2 inches 

 long, somewhat sticky-resinous, 

 thickly clothing the branches; 

 flowers yellow; flower heads 

 small, narrowly cylindric, com- 

 posed of 3 to 7 petal-like ray 

 flowers and 3 to 7 tubular disk 

 flowers, several heads borne in 

 loose, more or less flat-topped 

 clusters at the ends of the stems; 

 seed-like achenes silky, tipped with 

 a circle of small papery scales. 



This is one of the common 

 shrubs in the dry, semi-desert 

 areas in the Southwest and ex- 

 tending northward into the Great 

 Basin region. The plant, which 

 is quick to come into burned 

 areas or into areas which have 

 been depleted of vegetation due to 

 over-grazing or drought, serves as 

 a valuable protection against ero- 

 sion. It is generally considered 

 worthless as forage, but is some- 

 times browsed when other food is 

 scarce. It has been reported, in 

 some instances, to be poisonous to livestock. 



Occurrence. — YELLOWSTONE. GRAND TETON. MESA VERDE. BRYCE CANYON. ZION: 

 hills around Coalpits Wash, 4,000 feet. GRAND CANYON. South Rim, occasional: Grand 



Fig. 142. Broom snakeweed 

 (^Cutierrezia saroihrae) . 



