ZYGOPHYLLACEA. 159 
1. Larrea mexicana, Moric. Pl. Nouv. d’Am. p. 71, t. 48; Gray, Gen. Il. ii. 
t. 147. | | 
Zygophyllum tridentatum, DC. Prodr. i. p. 706 ; Calques des Dess. Fl. Mex. 159. 
Texas; New Mexico; Carirornra.—Norta Mexico, Sonora Alta (Couléer, 778), San 
Luis Potosi (Galeotti, 1362), without locality (Gregg). Hb. Kew. 
| 3. SERICODES. | 
Sericodes, A. Gray, Pl. Wright. i. p. 28; Benth. et Hook. Gen. Plant. 1. p. 265. 
Limited to this species : — 
1. Sericodes greggii, A. Gray, Pl. Wright. i. p. 28, in adnot. 
Norra Mexico, San Lorenzo (Gregg). 
4, GUAIACUM. 
Guaiacum, Linn. Gen. Plant. n. 518; Benth. et Hook. Gen. Plant. 1. p. 267. 
Shrubs or. trees, about eight species, restricted to the northern part of South America, 
West Indies, Central America, and Subtropical North America. 
1. Guaiacum coulteri, A. Gray, Pl. Thurb. p. 312. 
Norra Mexico, between Rayon and Ures, Sonora (Thurber ; t Coulter, 779). Hb. 
Kew. 
It is possible that this and the next are the same species; but the material at Kew is 
insufficient to decide the question. 
92. Guaiacum guatemalense, Pl. MS. in Hb. Kew. 
Guaremaxa, hot plains of Zacapa (Skinner), Acasaguastlan (Bernoulli). Hb. Kew. 
3. Guaiacum parvifolium, Pl. in Gray, Pl. Wright. i. p. 29. 
Sour Mxxico, between Tehuantepec and the Pacific Ocean (Andrieua, 475). Hb. 
Kew. 
4. Guaiacum verticale, Ort. Dec. viii. p. 93. 
Guaiacum sloanei, Shuttl. 
New Spain.—Foripa, Banamas, and San Domingo. 
5. CHITONIA. 
Chitonia, Moc. et Sessé, DC. Prodr. i. p. 707; Benth. et Hook. Gen. Plant. i. p. 268. 
‘1. Chitonia mexicana, Moc. et Sessé in DC. Prodr. i, p. 707; Zuce. Nov. Stirp. 
fasc. i. p. 855, t. 171; DC., Calques des Dess. Fl. Mex. xxiv. c. 
SourH Mexico, Zimapan (Coulter, 784), Oaxaca (Ghiesbreght ; Galeotti, 1445). Hb. 
Kew. 
