152 .COMPOSITA. 
[Xanthium spinosum, Linn., the commonest species all over the world, may 
ebe expected to occur in Mexico. | 
89. TRAGOCEROS. 
Tragoceros, H. B. K. Nov. Gen. et Sp. iv. p. 248, t. 385; Benth. et Hook. Gen. Plant. ii. p. 356. 
An exclusively Mexican and Central-American genus of annual herbs. 
1. Tragoceros flavicomum, DC. Prodr. v. p. 533. 
Sout Mexico, near Tehuantepec, Chiguitan, and Iztaltepec (Alaman). 
2. Tragoceros microglossum, DC. Prodr. v. p. 533. 
Souta Mexico, Leon, beyond Guanajuato (Mendez); GuatemMata, Santa Catarina 
(Bernoulli, 770). Hb. Kew. 
3. Tragoceros schiedeanum, Less. in Linnea, ix. p. 269. 
Souta Mexico, Malpays de Naulingo (Schiede & Deppe). 
4, Tragoceros zinnioides, H. B. K. Nov. Gen. et Sp. iv. p. 249, t. 385. 
Zinnia bicuspis, DC. Prodr. v. p. 535, et Calques des Dess. Fl. Mex. 578. 
SoutH Mexico, between Ario, Aguasarca, and Volcan de Jorullo, 2400 to 6000 feet 
(Humboldt & Bonpland), Ario, Michoacan (Galeotti, 2455); Nicaragua, Granada 
(Grsted, 227). Hb. Kew. 
90. PHILACTIS. 
Philactis, Schrad. Ind. Sem. Hort. Gott. 1881, ex DC. Prodr. v. p. 584; Benth. et Hook. Gen. 
Plant. i. p. 356. 
An exclusively Mexican genus of herbs. 
1. Philactis longipes, A. Gr. in Proc. Am. Acad. xv. p. 35. 
Norta Mexico, region of San Luis Potosi, 6000 to 8000 feet (Parry & Palmer, 465). 
Hb. Kew. 
2. Philactis zinnioides, Schrad. Ind. Sem. Hort. Geett. 1831; DC. Prodr. v. 
p. 534. 
Mexico. 
91. ZINNIA. 
Zinnia, Linn. Gen. Plant. n. 974; Benth. et Hook. Gen. Plant. ii. p. 357. 
About a dozen herbaceous and half-shrubby species, inhabiting Mexico and the 
countries immediately to the north. Two or three species have become naturalized in 
other countries. 
1. Zinnia acerosa, A. Gr. Pl. Wright. i. p. 105. 
Diplothriz acerosa, DC. Prody. v. p. 611. 
Texas.—Norta Mexico, San Luis Potosi (Berlandier), Hb. Kew. 
