992 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



52. Neomammillaria tetracantha (Salm-Dyck) Britt. & Rose, Cactaceae 4: 

 106. 1923. 



Mammtllaria tetracantha Salm-Dyck; Pfeiff. Enum. Cact. 18. 1837. 



Mammlllana ohconeUa Scheidw. Hort. Belg. 4: 93. 1837. 



Mammillaria doUchocentra Lem. Cact. Aliq. Nov. 3. 1838. 



Mammillaria rigUllspina Hildmann, Monatsschr. Kakteenk. 3: 112. 1893. 



Mexico, the range not known. 



Nearly globose, 6 to 8 cm. in diameter ; axils of tubercles with scant per- 

 sistent wool ; tubercles 8 to 10 mm. long, obscurely 4-angled ; areoles small, at 

 first lanate, somewhat 4-angled ; spines 4, all radial, slender, the 3 lower equal, 

 the upper one incurved, longer, 25 mm. long, w^hen young all yellowish white, 

 in age grayish yellow or brown; flowers numerous from near the top of the 

 plant, small, pinkish to rose-colored ; inner perianth segments narrowly lanceo- 

 late, acuminate. 



53. Neomammillaria elegans (DC.) Britt. & Rose, Cactaceae 4: 107. 1923. 

 Mammillaria geminispina DC. Mem. Mus. Hist. Nat. 17: 30. 1828. Not 31. 



geminispina Haw. 1824. 



Mammillaria elegans DC. MCm. Mus. Hist. Nat. 17: 11. 1828. 



Mammillaria acanthopMcgma Lehm. Delect. Sera. Hort. Hamb. 1832. 



Mammillaria supertexta Mart. ; Pfeiff. Enum. Cact. 25. 1837. 



Mammillaria dyckiana Zucc. ; Pfeiff. Enum. Cact. 26. 1837, 



Mammillaria klugii Ehrenb. Bot. Zeit. 2: 834. 1844. 



Mammillaria meisneri Ehrenb. Bot. Zeit. 2: 834. 1844. 



MammiUaria kunthii Ehrenb. Bot. Zeit. 2: 835. 1844. 



Mammillaria splendens Ehrenb. Allg. Gartenz. 17: 242. 1849. 



Central Mexico. 



Simple, obovate to globose, 5 cm. in diameter, somewhat umbilicate at apex ; 

 tubercles ovate, naked in their axils, not lactiferous ; spine areoles tomentose 

 when young ; radial spines stiff, bristle-like, 25 to 30, white, spreading ; central 

 spine 1 (sometimes 2 or 3), rigid. 



Related to this species are Mammillaria conspieua Purpus (Monatsschr. 

 Kakteenk. 22: 163. 1912) and M. microthcle Miihlenpf. (Allg. Gartenz. 16: 11. 

 1848; Cactus bispinus Coulter, Contr. U. S. Nat. Herb. 3: 101. 1894). 



54. Neomammillaria pseudoperbella (Quehl) Britt. & Rose, Cactaceae 4: 

 109. 1923. 



Mammillaria pseudoperbella Quehl, Monatsschr. Kakteenk. 19: 188. 1909. 



Oaxaca and elsewhere. 



Simple or with few branches, globose to short-cylindric, very spiny, de- 

 pressed at apex ; tubercles short-cylindric ; radial spines 20 to 30, setaceous, 

 white, short ; central spines 2, one erect, the other turned backward. 



55. Neomammillaria dealbata (Dietr.) Britt. & Rose, Cactaceae 4: 110. 1923. 

 MammiUaria dealbata Dietr. Allg. Gartenz. 14: 309. 1845. 



Valley of Mexico and elsewhere in Central Slexico. 



Globose, to short-cylindric, glaucous, more or less depressed at apex but 

 almost hidden by the many closely appressed spine clusters; axils of tubercles 

 and young spine areoles densely lanate but in age glabrate; radial spines 

 about 20, white, short, appressed ; central spines 2, much stouter and longer 

 than the radials, sometimes 1 cm. long, the upper ones often erect, white be- 

 low, brown or black at tip ; flowers small, carmine ; fruit clavate, red ; seeds 

 brown. 



