(and probably all the others) have the flower and fruit 
sessile upon the lower part of the tubercle, and elevated 
above the axil, much as in M. macromeris ; but unlike that 
plant, the lower part of the tubercle is entirely distinct 
from the upper one.” 
The species represented on Plate 7279 a good deal 
resembles that of Engelmann’s M. fissurata, but is a very 
much larger plant, the tubercles are not so ovate, are 
perfectly smooth (not warted and fissured), and the 
perianth is larger and longer. 
As the propriety of adopting the specific name (M. 
prismatica) here employed may be traversed from being 
founded on an erroneous citation of Lemaire’s Hort. Univ., 
I should add, that I think it has better claim for adoption 
than the earlier of M. retusa and M. aloides, as being more 
significant, as the first given to the species, and as being 
everywhere recognized where Cacti have been growing or 
studied for upwards of half a century. 
About a dozen species of Mammillaria have been re- 
ferred to Anhalonium, all natives of Andean regions, from 
Northern Mexico, southward to Peru. M. prismatica was 
discovered in 1838 by Galeotti, near San Louis de Potosi, 
in Mexico, at an elevation of seven thousand to eleven — 
thousand feet. The specimen here figured flowered in the 
Succulent House of the Royal Gardens in September, 1889, 
when the flowers were, as represented, pure white; but 
they are described as rose-coloured by Salm Dyck. The 
specimen was purchased from C. Runge, of St. Antonio, 
Texas, in 1888.—J. D. H. 
Fig. 1, Flower; 2, petal:—both slightly enlarged. 
