74 Muhlenbergia, Volume 5 



A case in hand is another of Nuttall's names. Cactus cali- 

 formats, the Cereus californicus of Torrey and Gray's Flora. 

 There can be no reasonable doubt in my mind that Nuttall found 

 our now familiar velvet cactus (Engelmann's Cereus Emory i) at 

 San Diego, and that it is the only plant now growing in the vi- 

 cinity of San Diego answering to the description given by Nut- 

 tall. But no specimens collected by Nuttall are known to me 

 to exist, and the circumstantial evidence available to me can not 

 be more complete than that I possessed in the case of the two 

 species of Rhus. It is possible, but not reasonable to suppose, 

 in view of our present knowledge, that Engelmann was right in 

 his supposition that Nuttall's Cereus californicus was based on 

 plants which he had named Opuntia serpentina. Opuntia ser- 

 pentina, as it commonly exists around San Diego, is not an erect 

 growing species; Cereus californicus was described as erect, with 

 yellow flowers and dry spiny fruit; Cereus Emoryi is erect in 

 habit, with yellow flowers and spiny fruit which is at first juicy 

 with a rich red pulp, but in age becomes drv, and may have 

 been so found by Nuttall. 



Now, if I am to use my own judgment, and follow strictly 

 the law of priority, I must reinstate Nuttall's name Cereus cali- 

 fornicus, and treat Engelmann's Cereus Emoryi as a synonym, 

 after more than fifty years of recognition. I intend to continue 

 to write Cereus Emoryi as the name of this plant, with C. cali- 

 fornicus as a synonym; but another critical botanist has ac- 

 knowledged that I am right in my recognition of Nuttall's plant, 

 and possibly his name will be reinstated upon the revision of the 

 genus. 



In traversing the desert plains of Arizona in 1902, I found 

 a tiny cactus growing in the shade of bushes on the Gila, the 

 slender cylindrical stems curiously proliferous from the base, 

 which I decided to be a new species, naming it Mammillaria 

 Thornberi, for Professor J. M. Thornber, who had found the 

 plant almost at the same time. It has since been sent to me by 

 Dr. R. K. Kunze, who reported it as quite rare. I collected 

 more than a thousand plants, but unfortunately all have per- 

 ished from lack of suitable care. I am now convinced that this 



