] 38 CALIFORNIA ACADEMY OF SCIENCES. 



Larrea Mexicana Moricand. — Nearly throughout the 

 whole regiou. 



Erodium Texanum Gray. — Calmalli and northward. 



Erodium cicutarium L'Her. — Magdalena Island. Half a 

 dozen plants recently introduced. 



OxALis Wrightii Gray. — El Eancho Yiejo. 



OxALis LATIFOLIA HBK. — Identified by Prof. William 

 Trelease, who states that the fruit does not exactly agree 

 with his description. — Magdalena and Santa Margarita Is- 

 lands, Oomondu, Purisima. 



Ptelea aptera Parry. — Las Huevitas. 



Cneoridium dumosum Hook. — Las Huevitas. 



Castela tortuosa Liebm. ? Nearest to the description 

 of this species, but perhaps distinct. A tangled, thorny 

 bush 2-3 feet high. The specimens are without flowers. — 

 Magdalena Island. 



Kceberlinia spinosa Zucc. Flowers light yellow. — San 

 Jorge. 



BuRSERA HiNDSiANA Bentli. The number of leaflets varies 

 from one to nine, and it therefore seems hardly necessary 

 to retain the var. rhoifolium for three-leaved specimens, as 

 has been done by Engler, in Monog. Burseraceae, p. 58. — 

 Magdalena and Santa Margarita Inlands, Comondu, Sau 

 Gregorio. "Copal." 



BuRSERA MICROPHYLLA Gray. A small aromatic bush or 

 tree. — Magdalena and Santa Margarita Islands. 



BuRSERA ODORATA. A bush or small tree 6-10 feet high, 

 trunk 4-6 inches in diameter, glabrous, with smooth bark: 

 leaves crowded at the ends of the branchlets, odd pinnate 

 with three pairs of leaflets: leaves little more than an inch 

 long; rachis barely margined: leaflets sessile, oblong ovate, 

 acuminate or obtuse, entire, midvein prominent, 14 mm. 



