106 JOURNAL OF THE ARNOLD ARBORETUM [vol. ii 



sources practically nothing else has been published regarding this Texas 

 plant which has always been assumed to be Pistacia mexicana IIBK. 



In 1902 I began a study of the genus Pistacia in order to ascertain the 

 botanical relationships oi Pistacia veraL., the cultivated Pistache nut, which 

 I was endeavoring to introduce into culture on a commercial scale in Cali- 

 fornia, Arizona and other Southwestern States. I soon satisfied myself 

 from a study of the material preserved in the principal old-world and 

 American herbaria that Pistacia mexicana HBK. was very different from 

 any old-world species, but in the absence of flowers it was difficult to come to 

 any decision as to the true relationship. 



Mr 



Mr 



Farm, was sent to the mouth of the Pecos River in Valverde County, Texa.s, 

 to secure flowering specimens of this plant. Mr. Headley secured some 

 good specimens of both sexes, with photographs. A study of this material 

 showed at once that it could not belong to a species of Rhus as supposed 

 by Gray, but was very near Pistacia. 



In March, 1911, Prof. S. C. Mason, aided by Mr. Stephen H. Hastings 

 and Mr. R. E. Blair, collected additional and much better material and 

 photographs in the same general region near the junction of the Pecos River 

 with the Rio Graude. This additional material, together with Professor 

 Mason's ample notes made on this and on two previous trips in March and 



good 



species 



Tiie Pistacia mexicana HBK. was based on fruiting specimens collected 

 at Chilpancingo in the State of Guerrero about 750 miles south of Valverde 

 County, Texas. In the principal American herbaria there is fairly abundant 

 material from the States of Puebla and Oaxaca which adjoin Guerrero, and 



Chilp>ancingo 



Mad 



»> 



May 25, 1903, fruiting branch) and some fn „^_, 



which doubtless belongs to Pistacia mexicana HBK. A single fruiting 

 specimen in the National Herbarium at Washington, D.C. (No. 867188), 

 collected by Mr. O. F. Cook (No. 60, June 1, 190G) from "rough lime- 

 stone country between Nenton and Candalaria, Dept. de Huehuetenango 



may 



Species but looks somewliat different. 



In May, 1912, Mr. C. A. Purpus collected abundant material at Tehua- 



May 



photograph 



seed, of which a very small percentage (38 out of 1754) germinated, and 

 gave rise to plants (C.P.B. No. 7581) now growing In the greenhouses of 



in California. 



Industry 



On the other hand, there is some good material, mostly of the fruiting 



Mexican 



