FAMILIES OF PLANTS 
121 
39. Bracts of the involucre mostly equal and in one series. Groundsel 
( Senecio )____— _____ _ __(p. 135) 
39. Bracts of the involucre unequal and in more than one series. 40. 
40. Pappus double, the inner part of hairlike bristles, the outer of small scales 
or spines. Golden-aster (Chrysopsis) ______(p. 121) 
40. Pappus wholly of hairlike bristles. 41. 
41. Bracts of the involucre closely appressed. Never leaflike. Goldenrod 
(Solidago) _ _________ _____ (p. 125) 
41. Outer bracts of the involucre more or less leaflike. Aplopappus parryi^i p. 139) 
Broom snakeweed (Gutierrezia sarothrae) is a bushy plant with 
numerous erect stems from a somewhat woody base, 1 or 2 feet high. 
The leaves are very narrow, entire, and alternate. The heads are 
small but quite numerous, each 
head containing 3 to 7 disk flowers 
and about the same number of ray 
flowers, both yellow. 
Gumplant (Grindelia subal- 
pina ).—A biennial herb with usu¬ 
ally two or more stems that grow 
8 to 16 inches high. The basal 
leaves have slender petioles and 
are toothed, while the stem leaves 
are sessile but are narrowed to a 
" petiolelike base. The heads con¬ 
tain both ray and disk flowers and 
both are yellow. The ray flowers 
are numerous and the head when 
fully expanded is 1 or 2 inches 
broad. The involucre is very 
gummy and consists of numerous 
narrow bracts with the tips curved 
back. 
Golden-aster (Chrysopsis ).— 
These plants resemble asters, but 
the ray flowers as well as the disk 
flowers are yellow. Both stems and leaves are hairy. Three species 
have been identified in the park. They are quite similar but may 
be distinguished in the following manner: 
1. Hairs spreading and bristly. Chrysopsis hispida. 
1. Hairs appressed, at least on the leaves. 2. 
2. Leaves sessile or nearly so. Chrysopsis depressa . 
2. Leaves, except the uppermost, with slender petioles. Chrysopsis viilosa. 
Rabbitbrush ( Chrysothamnus ).—These shrubs are common on dry 
hills and plains and are very conspicuous when in full bloom in 
the latter part of the season. They often grow along with sage- 
Fxgure 96.—Gumplant. Yellow. Photo¬ 
graph by A. R. Sweetser. 
