152 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



Mammillaria frailiana (Brit, k Rose) Boedeker, Mammil.Vergl. 

 Schluss. 30. 1933. 



South end of San Esteban Island, Rempel 293 (sterile). 



It is also known from Ceralbo, Catalina, and Pichilinque Islands, 

 the latter being the type localit3\ It will probably be found also on the 

 adjacent part of the peninsula. A closely related species is il/. Verhaerti- 

 ana Boedeker, reported from Los Angeles Bay. 



IVlA^miLLARiA iNSULARis Gates, Cact. Succ. Jour. 10:25. 1938. 



Ildefonso Island, March 15, Rempel 17 Oh, on rocky ridge. Ensenada 

 de San Francisco, Sonora, ]\Iarch 10, Rempel 316. 



Central part of the Gulf of California; type from easternmost islet 

 of Smith Island, Los Angeles Bay, Baja California. A low cespitose 

 plant with purplish hooked spines. Doubtfully referred here also is 

 Rempel 325 (in part). All of his collections, made in Alarch, are sterile. 



Mammillaria multidigitata G. Lindsay, Cact. Succ. Jour. 19: 

 152. 1947. 



San Pedro Nolasco Island, ^larch 29, Rempel 302 \ February 6, 

 Dawson 1038. 



Apparently endemic to San Pedro Nolasco Island, this plant is re- 

 lated to M. albicans, but difiEers in its cespitose habit, its slender cylindri- 

 cal stems (not globose), and the appressed fine white radial spines. 

 Lindsay reports it as being abundant on the steep slopes of the island. 



Mammillaria Slevinii (Brit. Sc Rose) Boedeker, Mammil. Vergl. 

 Schluss. 44. 1933. 



San Francisco Island, i\Iarch 9, Rempel 101 (sterile). 



A rare and little known species related to AI. albicans and may be as 

 Craig (I.e. p. 262) surmised, conspecific with it. Known only from San 

 Francisco and San Jose Islands in the Gulf of California, Rose having 

 collected the type on the latter island. 



Opuntia Bigelovii Engelm., Proc. Am. Acad. Sci. 3:307. 1856. 



Angel de la Guardia Island, Puerto Refugio, January 26, Dawson 

 sine no. Turner's Island, Dawson sine no. Tiburon Island, January 25, 

 Dawson 1019. Tortuga Island, Rempel 210a. South end of San Esteban 

 Island, March 27, Rempel 292. 



A common cactus shrub of the northern part of the California Gulf 

 Region in IMexico and the United States; type from Bill Williams 

 River, Arizona. The Tortuga Island collection is the southernmost 

 record. All the above collections are sterile. 



