1640 CONTRIBUTIONS FROM THE NATIONAL. HERBARIUM 



Branching shrub; leaves narrowly lanceolate to narrowly linear, 3 to 8 cm. 

 long, 2 to 5 (rarely 10) mm. wide, strongh' revolute, acuminate, more or less 

 densely appressed-silky-pilose beneath; outer phyllaries lance-linear, usually 

 about two-thirds as long as the inner; involucre glandular-puberulous. " Arnica " 

 (San Luis Potosi); "hierba del aire" (Durango); "Montezuma de campo" 

 (Coahuila) . 



The plant is employed as a remedy for rheumatism 



11. Trixis haenkei Schultz. Bip. in Seem. Bot. Voy. Herald. 314. 1856. 

 Jalisco and Puebla; type from the Sierra Madre of northwestern Mexico. 

 Shrub; leaves lance-oblong or lanceolate, 3 to 14 cm. long, 1 to 4.5 cm. wide, 



entire or denticulate, green or grayish above, silky-pilose-tomentose beneath; 

 heads densely crowded, 1.5 to 2 cm. high. 



12. Trixis peninsularis Blake, Contr. U. S. Nat. Herb. 22: 654. 1924. 

 Cape Region of Baja California; type from San Jose del Cabo. 



Shrub; leaves short-petioled, the blades lanceolate or lance-elliptic, 4 to 8 

 cm. long, 8 to 20 mm. wide, acuminate, serrulate, revolute-margined, densely 

 silky-pilose beneath; heads 1.6 to 1.8 cm. high; outer phyllaries mostly linear, 

 two-thirds as long as the inner or less. 



13. Trixis megalophylla Greenm. Proc. Amer. Acad. 41: 270. 1905. 

 Known only from the type locality, between Sochi and Tlalkinsala, Guerrero. 

 Shrub; branches obscurely winged; leaves oblong-ovate or oval-oblong, the 



larger 7.5 to 17 cm. long, 2.5 to 6 cm. wide, entire or denticulate, revolute- 

 margined, glandular-puberulous and pilose beneath; heads 1.5 to 1.8 cm. high; 

 outer phyllaries lanceolate or oblanceolate, about equaling or exceeding the inner. 



14. Trixis nelsonii Greenm. Proc. Amer. Acad. 41: 270. 1905. 



Known only from the type locality, between San Crist6bal and Teopisca, 

 Chiapas. 



Leaves petioled, the blades elliptic to elliptic-obovate, 3 to 7 cm. long, 1 to 3 

 cm. wide, rugose above, denseh' griseous-tomentose beneath; petioles 5 to 8 

 mm. long; heads about 1.5 cm. high, rather crowded; involucre glandular- 

 pubescent, the outer phyllaries mostly oblanceolate, half or two-thirds as long 

 as the inner. 



15. Trixis rugulosa Robins. & Greenm. Proc. Amer. Acad. 40: 10. 1904. 

 Michoacdn, Guanajuato, and Queretaro; type not designated. 



Shrub; branches sometimes obscurely winged; leaves lanceolate, 3 to 8 cm. 

 long, 7 to 22 mm. wide, sparingly appressed-pilose beneath; inflorescence loose; 

 outer phyllaries two-thirds as long as the inner, or less. 



16. Trixis californica Kellogg, Proc. Calif. Acad. 2: 182./. 53. 1863. 

 Trixis suffrulicosa S. Wats. Bot. Calif. 2: 459. 1880. 



Trixis angustifolia latiuscula A. Gray, Syn. Fl. P: 410. 1884. 



Sonora to Coahuila, Zacatecas, and San Luis Potosi; Baja California and 

 islands; type from Cedros Island, Baja CaUfornia. CaUfornia to Texas. 



Shrub about 1 meter high; leaves lanceolate or oblong-lanceolate, 2.5 to 11 

 cm. long, 0.5 to 3 cm. wide, acuminate, entire or denticulate, scarcely revolute- 

 margined, green on both sides, beneath densely gland-dotted, otherwise nearly 

 or quite glabrous; heads 1.3 to 1.8 cm. high; outer phyllaries Hnear or lance- 

 linear. 



17. Trixis silvatica Robins. & Greenm. Proc. Amer. Acad. 40: 12. 1904. 

 Oaxaca; type from the Rio Tehuantepec. 



Leaves ovate-oblong, 5 to 8 cm. long, 2 to 3 cm. wide, thin, acuminate, sharply 

 dentate, glandular and finely pubescent beneath; heads 2 cm. long; outer phyl- 

 arie.s equaling or exceeding the inner. (Description compiled.) 



