PLANTJ3 NOViE THURBERIAN^. 305 



were gathered, and Erigeron Canadense and Oligomeris glaucescens were common. 

 Cereus giganteus occurs frequently along the table-lands, and near the villages of the 

 Pimos becomes very abundant. It was our good fortune to find this species both in 

 fruit and flower, aff'ording materials for the completion of its history, which has been 

 done by Dr. George Engelmann in a paper before referred to. The fruit of this Cereus 

 is an important article of food among the Indians of this region, who collect it in 

 *large quantities and roll it into balls, which keep well without other preparation. 

 The seeds from portions of this conserve, brought home, have promptly germinated, so 

 that this remarkable species is secured for our green-houses. 



" A visit was made to the Salinas Eiver, which, coming from the northeast, joins the 

 Gila below the Pimo villages. Its valley is broader than that of the Gila, but its 

 general character is the same. Specimens of two undetermined Leguminous trees 

 were collected, in fruit only, upon the table-lands, between the two rivers ; and a cu- 

 rious thorny shrub, forming the new genus Holacantha, was found in the same vicinity. 



" The party left the Gila in July ; and from that time until its arrival at El Paso, 

 in the middle of August, scarcely a day passed without severe rains. The route, 

 which was by the way of Tucson, Santa Cruz, Janos, and Corralitas, produced few 

 novelties. A new Mahastrum, however, was collected in Santa Cruz valley, and one 

 or two specimens of a new genus in Compositee Senecioneae. Between Corralitas and 

 El Paso, Amoreuxia Schiedeana * was abundant upon the sandy prairies, and in the 

 medanos, or sand-hills, through which the road passes near El Paso, along with Pent- 

 stemon ambiguum and Dalea scoparia. 



" Late in 1852, the party made a journey from El Paso, through the States of Chi- 

 huahua, Durango, Cohahuila, and Nuevo Leon, to Camargo, on the lower Eio Grande. 

 The route was almost precisely that taken by Dr. Wislizenus, to whose excellent ac- 

 count of the features of the country little can be added. From the lateness of the sea- 

 son, only a few botanical specimens were made. Among them, however, occurs Tri- 

 daas hicolor ; f an unpublished Dalea (D. Greggii, Gray), which was common along 



* The corolla, according to Mr. Thurber's memoranda, is " deep orange, with a brownish spot in the cen- 

 tre " ; approaching so nearly to De CandoUe's phrase, "Jlores rulelli" as to render it altogether probable that 

 the A. Schiedeana of Planchon is the original A. palmatifida, DC. — A. G. 



+ Tridax hicolor, Gray, PL Fendl., p. 104. Bachimba, Chihuahua, among rocks ; November. A single 

 specimen was gathered, of a taller plant than that of Wislizenus, from which the species was character- 

 ized, being a foot or two in height ; the head larger than in T. procumbens, and with rose-purple rays. The 

 lower leaves are opposite ; but all the upper alternate, and on veiy long petioles. The pappus, in the speci- 

 men, is not tinged with purple. — A. G. 



VOL. V. NEW SERIES. 42 



