STANDLEY TREES AND SHRUBS OP MEXICO 1447 



10-flo'w^sred, borne in a dense rounded terminal thyrse; phyllaries stramineous, 

 ovate-oblong, obtusish, striate; corollas white or nearly so; florets fragrant. 

 "Chimaliote" (El Salvador). 



22. Eupatorium thyrsoideum Moc; DC. Prodr. 5: 150. 1836. 

 Tepic, Colima, and Guerrero(?); tj'pe locality cited merely as Mexico. 



Stem terete or somewhat 4-angIed when young. In all other respects exceed- 

 ingly close to the preceding species, of which it may well prove a mere variety. 



Little known and in need of close field study. Including Eupatorium thyr- 

 soideum /3 pubcrum DC. op. cit. 151, merely a slightly hairy form. 



23. Eupatorium ortegae Robinson, Contr. Gray Herb. n. ser. 75: 10. 1925. 

 Durango; type from La Bajada. 



Smoothish shrub with slender terete branches; leaves opposite, slender-petioled , 

 deltoid-ovate, acuminate, sharply and rather coarsely dentate, abruptly con- 

 tracted at base, bright green and prominently reticulate on both surfaces, firm in 

 texture, subcoriaceous, 3.5 to 8 cm. long, 2.5 to 5 cm. wide; petiole 1.5 to 3 cm. 

 long; heads about 6 mm. high, thistle-shaped, borne in rounded, paniculately 

 disposed corymbs; pedicels bearing 3 to 7 linear-subulate bractlets; phyllaries 

 narrowly lanceolate, attenuate; corollas white. 



24. Eupatorium haenkeanum DC. Prodr. 5: 158. 1836. 

 Guerrero and Oaxaca; tj'pe locality stated merely as Mexico. 



Shrub with recumbent liana-like stems (LanglassS) ; branches round, rather 

 slender, puberulent to velutinous; leaves rhombic-ovate, gradually acuminate to 

 apex, more abruptly cuneate at base, entire to undulate or crenate-serrate, 

 firmly membranaceous, sparingly puberulent, 3-nerved, 6 to 8 cm. long, 3 to 

 5 cm. wide; petiole slender, 1 to 2 cm. long; heads about 20-flowered, long- 

 pediceled, in open compound leafy-bracted corymbose panicles; involucre sub- 

 turbinate; phyllaries elliptic-oblong, obtusish; corollas white. 



A somewhat more pubescent form has been distinguished as Eupatorium 

 haenkeanum ^ ? velutinum DC. Prodr. 5: 158. 1836. 



25. Eupatorium mendezii DC. Prodr. 5: 160. 1836. 



Guanajuato, San Luis Potosf, and Quer^taro; type locality at the west of 

 Guanajuato City. 



Shrub; stems round, slender; branches shortly velvety or covered with a 

 grayish crisped puberulence; leaves triangular-ovate or ovate-lanceolate, gradually 

 acuminate, serrate, puberulent above, tomentellous beneath, 3-nerved, 6 to 9 cm. 

 long, 2.5 to 4.5 cm. wide; petioles slender, 1 to 2 cm. long; heads about 25-flow- 

 ered, pedicellate, disposed in round-topped compound bracteate panicles; involucre 

 ovoid; phyllaries rhombic- or oblong-lanceolate, acute or acutish, pubescent, 

 usually brown or purple-tinged; corollas white. 



26. Eupatorium stillingiaefolium DC. Prodr. 5: 160. 1836. 

 Tamaulipas and Veracruz; type from Tamaulipas. 



Shrub, 1.3 to 2 meters high, obscurely puberulent, with habit and fohage as 

 in the preceding; leaves more deltoid-ovate and abruptly contracted or even 

 rounded at base; petiole 1.5 to 3.5 cm. long; heads 20 to 25-flowered; phyllaries 

 lance-oblong, all acute; corollas roseate. 



A little known species. 



27. Eupatorium collinum DC. Prodr. 5: 164. 1836. 

 Eupatorium iiigrescens Hook. & Arn. Bot. Beechey Voy. 297. 1840. 

 Kyrstenia collina Greene, Leaflets 1: 9. 1903. 



Widely distributed and frequent from Chihuahua and TamauHpas to Chiapas; 

 type from Tantoyuca, Veracruz. Guatemala, El Salvador, Nicaragua, and 

 Costa Rica. 



