FLOWERING PLANTS AND FERNS OF ARIZONA 605 



4. Mammillaria chlorantha Engelm. in Rothr., U. S. Geol. and Geog. 



Survey Rpt. 6: 127. 1878. 



Coryphantha chlorantha Britt. and Rose, Carnegie Inst. Wash. 

 Pub. 248. 4:43. 1923. 



Reported from Mohave County. Southwestern Utah and south- 

 eastern California. 



In M. chlorantha the central spines are 6 to 9 in number, 25 mm. 

 long, and the flowers yellowish or greenish yellow. M. deserti Engelm., 

 which has fewer central spines and the perianth segments purplish 

 tipped, also has been reported from Mohave County. M. cdversonii 

 (Coult.) Zeissold, a pink-flowered species with 12 to 14 central spines, 

 occurs in southern California. 



5. Mammillaria aggregata Engelm. in Emorv, Mil. Reconn. 157. 



1848. 



Coryphantha aggregata Britt. and Rose, Carnegie Inst. Wash. 

 Pub. 248. 4:47/ 1923. 



Southeastern quarter of the State, 3,000 to 7,000 feet 7 common in 

 rocky situations, May. Xew Mexico and Arizona. 



In Cactaceae of the Ives Exploration, Engelmann treated M. 

 aggregata as synonymous with Echinocereus coccineus Engelm., but in 

 the sketch on which the original description is based the tubercles 

 are arranged in crossed spirals, indicating that Emory's plant is not 

 an Echinocereus. 



6. Mammillaria arizonica Engelm. in Brewer and Wats., Bot. Calif. 1: 



244. 1876. 



Coryphantha arizonica Britt. and Rose, Carnegie Inst. Wash. 

 Pub. 248. 4:45. 1923. 



Apache County to Mohave, Gila, and Yavapai Counties, mostly 

 north of the Mogollon Escarpment, common, 5.000 to 8,000 feet, 

 May and June, type from northern Arizona. Southern Utah and 

 Arizona. 



Plants grown at low altitude in southern Arizona retain the char- 

 acteristically narrow, deep-pink perianth segments and dark spines. 



7. Mammillaria tetrancistra Engelm., Amer. Jour. Sci. ser. 2, 14: 



337. 1852. 



Phellosperma tetrancistra Britt. and Rose, Carnestfe Inst. 

 Wash. Pub. 248. 4: 60. 1923. 



Mohave, southern Yavapai, Maricopa, Pinal, Pima, and Yuma 

 Counties, low desert regions. Southwestern Utah, southern Nevada, 

 Arizona, and southern California. 



8. Mammillaria mainae K. Brandeg., Zoe 5: 31. 1900. 



Santa Cruz and Pima Counties, 2,000 to 4,000 feet, July. Arizona 

 and Sonora. 



The plants occur on rocky hills but more commonly on plains with 

 ironwood and mesquite. 



