1484 CONTRIBUTIONS FEOM THE NATIONAL HERBARIUM 



21. DYSCRITOTHAMNUS Robinson, Contr. Gray Herb. n. ser. 65: 25, 



pi. 1. 1922. 

 1. Dyscritothamnus filifolius Robinson, Contr. Gray Herb. n. ser. 65: 26. 

 pi. 1. 1922. 



Known only from the tj'pe locality, between Las Ajuntas and Las Ranas, near 

 boundary between Guanajuato and Hidalgo. 



Shrub 30 cm. high, glabrous; leaves alternate, nearly filiform, 2 to 3 cm. long, 

 0.5 to 0.8 mm. wide, nerveless; heads few, in terminal cymose panicles, 12 to 

 13 mm. high, about 10-flowered; phyllaries 2 or 3-seriate, somewhat graduate, 

 lanceolate, acuminate, subscarious; receptacle paleaceous; corollas all tubular, 

 very slightly zygomorphous; achenes obovoid, villous-hirsute, 2.5 mm. long; 

 pappus of numerous unequal bristles, plumose below. (Description compiled.) 



This genus is |)erhaps more closely allied to the Asterieae than to the Eupa- 

 torieae. 



22. SELLOA Spreng. Nov. Prov. Hal. 36. 1819. 



1. Selloa glutinosa Spreng. Nov. Prov. Hal. 36. 1819. 



Gymnosperma glutitiosum Less. Syn. Gen. Comp. 194. 1832. 



Gymnospermn corymbofium DC. Prodr. 5: 312. 1836. 



Gymnosperma multifiorum DC. Prodr. 5: 312. 1S36. 



Gymnospermn scopariurn DC. Prodr. 5: 312. 1836. 



Chihuahua to Chiapas. Texas to Arizona; type a cultivated plant, wrongly 

 ascribed to Brazil. 



Woody below, much branched, 1 meter high or less, glutinous, essentially gla- 

 brous; leaves alternate, sessile, often with fascicles in their axils, linear to narrowly 

 elliptic-lanceolate, 2 to 7 cm. long, 2 to 6 mm. wide, triplinerved, punctate, entire; 

 heads yellow, about 4 mm. high, in dense corymbose-panicled cymes; phyllaries 

 pale, subcoriaceous, obtuse, with narrow scarious margin, sometimes obscurely 

 herbaceous-tipped; ligules about 6, not exceeding disk; disk flowers about 6; 

 achenes oblong, puberulous, 4or 5-ribbed;pappus none. " Jarilla" (Nuevo Le6n); 

 "mota" (Aguascalientes); "mariquita," "tatalencho" (Zacatecas); "motita" 

 (San Luis Potosi); ''cola de zorra" (Chihuahua); "xonequitl" (Nahuatl); 

 "hierba pegajosa" (Nuevo Le6n); "yucu ndede" (Oaxaca, Mixtec, Seler); "zazal" 

 (Mexico); "pegajosa," "escobilla" (Valley of Mexico). 



In popular medicine a decoction of the plant is employed as a remedy for diar- 

 rhea, and a solution of the gum is used externally as a remedy for rheumatism, 

 ulcers, etc. 



23. QUTIERREZIA Lag. Gen. & Sp. Nov. 30. 1816. 



Herbaceous to suffruticose, low, much branched, more or less glutinous; leaves 

 alternate, linear-filiform to oblanceolate, punctate, 1-nerved or rarely triplinerved, 

 entire; heads small or very small, yellow, cymose-panicled; involucre graduate, 

 few-seriate, of coriaceous, often green-tipped phyllaries; achenes turbinate or 

 obconic, silky; pappus of about 10 linear-oblong to linear-lanceolate, scarious- 

 paleaceous, persistent squamellae, as long as the achene or usually shorter, in the 

 ray about half as long as in the disk (in our species) . 

 Heads verj^ small, cylindric; raj' flowers 1 or 2, disk flowers 1 to 3. 



Heads sessile, fasciculate in glomerules of 2 to 5; rays solitary; disk flowers 

 1 or 2 1. G. lucida. 



Heads often pediceled, not fasciculate-glomerate; rays 2; disk flowers 2 or 3. 



2. G. digyna. 

 Heads turbinate to subglobose; ray flowers 3 to 12, disk flowers 1 to 12. 



Involucre 2.5 to 4 mm. high; leaves linear-filiform to narrowly linear, 1.5 mm. 

 (rarely 2.5) wide or less. 

 Heads slenderly cylindric-turbinate, about 1.5 mm. thick; ray flowers 

 4 or 5, disk flowers lto3 3. G. microcephala. 



