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^ or 5-nerved, glabrous; pappus wanting. 



1. Gymnosperma corymbosurn DC. Prodr. 5: 312. 1836. 



Type locality: "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. XANTHOCEPHALTJM 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 wrightii A. Gray, PI. Wright. 2: 78. 1853. 



Type locality: "Margin of dried-up streams, between Barbocomori and Santa 

 Cruz, Sonora." 



Range: 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. Mem. Soc. Phys. Hist. Nat. Geneve 7: 265. pi. 1. 1836. 

 Type locality: "Arkansas." 



Range: Kansas and Oklahoma to Texas and eastern New Mexico. 

 New Mexico: Roswell (Earle 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 paleae, 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 1. G. sphaerocephnln. 



Perennials; heads less than 4 mm. broad. 



Disk and ray flowers in each head 1 or 2 cadi 2. G. glomerella. 



Disk and ray flowers in each head 3 to 7 each. 



Branches, leaves, and outer bracts densely lepidote- 



scurfy 3. G . fwfuracea. 



