656 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
12. GYMNOSPERMA Less. 
Perennial herb, often woody at the base, glabrous, resinous-viscid; leaves alternate, 
entire, linear or linear-lanceolate; heads small, yellow-flowered, in fastigiately 
corymbose cymes; bracts obtuse; rays very small; achenes oblong, slightly com- 
pressed 4 or 5-nerved, glabrous; pappus wanting. 
1. Gymnosperma corymbosum DC. Prodr, 5: 312. 1836. 
TyPE Loca.ity: ‘‘In Mexico circa Matamoros.”’ 
RANGE: Western Texas and southern Arizona to Mexico. 
New Mexico: Bear Mountains; Gila Hot Springs; Florida Mountains; Animas 
Mountains; San Luis Mountains; Organ Mountains; White Mountains. Dry hills and 
rocky canyons, in the Upper Sonoran Zone. 
13. XANTHOCEPHALUM Willd. 
Slender branched annual with alternate, entire, linear or linear-oblong leaves; 
heads loosely cymose, about 10 mm. broad; rays about 12, bright yellow, oblong, as 
long as the disk; achenes truncate, with an obscure coroniform border. 
1. Xanthocephalum wrightii A. Gray, Proc. Amer. Acad. 8: 632. 1873. 
Gutierrezia wrightti A. Gray, Pl. Wright. 2: 78. 1853. 
TypE Locauity: “Margin of dried-up streams, between Barbocomori and Santa 
Cruz, Sonora.”’ 
RanGeE: Southern Arizona and New Mexico to Mexico. 
New Mexico: Black Range; Mogollon Mountains. Upper Sonoran and Transition 
Zones. 
14. AMPHIACHYRIS Nutt. 
Slender annual, effusely corymbose-branched; leaves linear to filiform; heads very 
numerous, long-pedunculate, hemispheric, with 10 to 12 firm, coriaceous, ovate to 
oval bracts; rays 5 to 10, oval or oblong; disk flowers 10 to 20, sterile; achenes with 
minute coroniform pappus. 
1. Amphiachyris dracunculoides (DC.) Nutt. Trans. Amer. Phil. Soc. n. ser. 7! 
313. 1841. 
Brachyris dracunculoides DC. Mém. Soc. Phys. Hist. Nat. Geneve 7: 265. pl. 1. 1836. 
Tyee Locauity: ‘‘Arkansas,”’ 
Rance: Kansas and Oklahoma to Texas and eastern New Mexico. 
New Mexico: Roswell (£arle 347), Plains, in the Upper Sonoran Zone, 
15. GUTIERREZIA Lag. SNAKEWEED. 
Slender, viscid, much branched herbs or shrubby perennials, with slender alternate 
linear leaves and numerous small heads of yellow flowers, these either solitary or 
clustered; rays 1 to 8; achenes short, obovate or oblong, terete or 5-angled; pappus of 
numerous paleee, these often minute. 
It is said that the Navahos chew these plants and apply them to the stings of bees, 
wasps, or ants, 
KEY TO THE SPECIES. 
Annual; heads about 5 mm. broad. .....2........2..2...-.-. Ll. G. sphacrocephala. 
Perennials; heads less than 4 mm. broad. 
Disk and ray flowers in each head 1 or 2 each. ......-.--.- 2. G. glomerella. 
Disk and ray flowers in each head 8 to 7 each. 
Branches, leaves, and outer bracts densely lepidote- 
Scurly. 2... eee eee ec ee ccc ee cece eee cece 3. G. furfuracea, 
