518 CACTACEA. . 
172**, Mamillaria pleiocephala, Regel et Klein, Ind. Sem. Hort. Petrop. 
1860, p. 47. 
Mexico (Karwinski). 
173. Mamillaria polycentra, Bergm. in Otto & Dietr. Allg. Gartz. viii. p. 130 ; 
Walp. Rep. ii. p. 297. 
MEXIco. | 
_ 174. Mamillaria polycephala, Miihlpf. in Otto & Dietr. Allg. Gartz. xill. 
p. 346; Walp. Rep. v. p. 810. 
Sovm Mexico, Real del Monte (ex Mihlenpfordt). 
175. Mamillaria polyedra, Mart. in Act. Nov. Nat. Cur. xvi. pars 1, p. 326, t. 18. 
Sour Mexico, near Oaxaca, at Zimapan and Ismiquilpan (Karwinski, Ehrenberg). 
Hort. Kew. 
Var. 3. levior, Salm Dyck, Cact. ed. 2, p. 17. 
Mamillaria anisacantha, Hort. ex Salm Dyck, loc. cit. 
176. Mamillaria polygona, Salm Dyck, Cact. ed.'2, p. 120. 
MEXxIco. 
177. Mamillaria polymorpha, Scheer in Otto & Dietr. Allg. Gartz. xiv. p. 573. 
MEXICO. 
178. Mamillaria polythele, Mart. in Act. Nov. Nat. Cur. xvi. pars 1, p. 328, t.19; 
Labour. Cact. p. 51. 
Labouret (oc. cit.) makes the following varieties, some of which are kept distinct here 
on the authority of Ehrenberg :— 
Var. «. polythele. 
SoutH Mexico, Ismiquilpan (Ehrenberg). Hort. Kew. 
Var. 6. quadrispina, Mart. loc. cit. p. 829 (species). 
Sout Mexico, Puerto de Ismiquilpan (Ehrenberg). 
Var. y. hexacantha, Salm Dyck. 
Mamillaria columnaris, Mart. loc. cit. p. 330 (species). 
Var. 6. setosa, Salm Dyck. 
SoutH Mexico, Barranca de los Majadas, in forests on mossy cliffs (Ehrenberg). 
Var. «. aclculata, Salm Dyck. 
Var. Z. latimamma, Salm Dyck. 
179. Mamillaria pomacea, Ehrb. in Otto & Dietr. Allg. Gartz. xvi. p. 267; 
Walp. Ann. ii. p. 674. 
MEXIco. 
