NOTES ON CACTEiE. 115 



The plant is of more slender growth than the San Diego species, 

 with naked or sparsely woolly axils, much larger, more or less rose- 

 colored flowers, and longer slender, subulate, style-divisions. In the 

 twoscore plants^ I have seen^ the flowers were all hermaphrodite. 

 A stouter form with stronger spines sent recently by Captain Porter 

 from Topolobampo, Sinaloa, appears to answer to that mentioned 

 by Scheer as occurring at Guaymas. 



The species is very near M. Grahavii, differing chiefly in the less 

 numerous spines, and both may belong to previously described 

 Mexican forms. 



Mamillaria (Eumamillaria) dioica. M. Goodrichii of Engel- 

 mann, not of Scheer. Simple or csespitose, or occasionally branch- 

 ing above; beginning to flower at one inch or less, but attaining a 

 height of 6-10 inches. Tubercles green or sometimes glaucous, 

 cylindrical, often angular ; axillae sparsely woolly in the growing 

 part, bearing 4-15 set^e, often as long as the tubercle; outer spines 

 usually white, radiant, 11-22, covering the whole plant, centrals 

 1-4, the superior turned upward among the radials, the lowest 

 longer and stouter and porrect, 8-15 mm. long: flowers 10-22 mm. 

 long, yellowish-white, sometimes reddish, incompletely dioecious; 

 petals lanceolate-acuminate, much longer and more spreading in the 

 male flowers; fruit, like the flowers, borne in a circle near the top, 

 clavate or oval, scarlet, 10-25 mm. long; seeds as in most of the 

 related species black, somewhat pyriform and minutely pitted. 



From San Diego a short distance north but southward to Cape 

 St. Lucas always so far as known near the coast. Some plants 

 brought by Mr. Anthony from San Juanico, Baja California, have 

 the radial spines brown, and plants from San Jose del Cabo show 

 colored rings of growth. It has been found as far as known on 

 none of the islands excepting Todos Santos near Ensenada. 



M. DIOICA var. insularis. Caches Palmeri Coult. Contr. Nat. 

 Herb. Ill, 108, not M. Palmeri Jacobi, in Otto and Dietr. Alg. 

 Gart. xxiv (1856) 82. 



Differing from the type in its more densely csespitose form, more 

 woolly axils, and shorter spines, which are usually whiter, shorter, 

 more numerous, and the centrals ordinarily straight. Flowers 

 and fruit as in the type. 



This i^lant was named as a species principally because of 



