STANDLEY TREES AND SHRUBS OF MEXICO. 995 



white-woolly when young, nearly naked in age ; radial spines 18 to 20, acicular, 

 6 to S mm. long, white ; central spines 2 to 4, stouter than the radials, spread- 

 ing, 8 mm. long, reddish brown ; flowers small, somewhat distant from the apex 

 of the plant. 



68. Weomammillaria spinosissima (Lem.) Britt. & Rose, Cactaceae 4: 117. 

 1923. 



ManimiUaria spinosissima Lem. Cact. Aliq. Nov. 4. 1838. 



Mammillaria polycentra Berg, Allg. Gartenz. 8: 130. 1840. 



MammiUaria auricoma Dietr. Allg. Gartenz. 14: 308. 1846. 



Mammillaria polyacantlia Ehrenb. Allg. Gartenz. 16: 265, 1848. 



MammiUaria polyactina Ehrenb. Allg. Gartenz. 16: 266. 1848. 



MammiUaria licpatica Ehrenb. Allg. Gartenz. 16: 267. 1848. 



MammiUaria pomacea Ehrenb. Allg. Gartenz. 16: 267. 1848. 



Mammillaria pulcherrima Ehrenb. Allg. Gartenz. 17: 249. 1849. 



Mammillaria pretiosa Ehrenb. Allg. Gartenz. 17: 250. 1849. 



Mammillaria caesia Ehrenb. Allg. Gartenz. 17: 251. 1849. 



Mammillaria mirffbilis Ehrenb. Allg. Gartenz. 17: 251. 1849. 



Mammillaria pruinosa Ehrenb. Allg. Gartenz. 17: 261. 1849. 



Mammillaria seegeri Ehrenb. Allg. Gartenz. 17: 261. 1849. 



MammiUaria haseloffii Ehrenb. Allg. Gartenz. 17: 303. 1849. 



Mammillaria lierrmannii Ehrenb. Allg. Gartenz. 17: 303. 1849. 



MammUlaria aurorca Ehrenb. Allg. Gartenz. 17: 303. 1849. 



Mammillaria linkeana Ehrenb. Allg. Gartenz. 17: 308. 1849. 



Mammillaria vulpina Ehrenb. Allg. Gartenz. 17: 308. 1849. 



Mammillaria eximia Ehrenb. Allg. Gartenz. 17: 309. 1849. 



Mammillaria isabeUina Ehrenb. Allg. Gartenz. 17: 309. 1849. 



Mammillaria ulideana Salm-Dyck, Cact. Hort. Dyck. 1849. 83. 1850. 



Mammillaria castaneoides Lemaire ; Labour. Monogr. Cact. 37. 1853. 



Mammillaria sanguinea Haage ; Kegel, Act. Hort. Petrop. 8: 276. 1883. 



MaiiiDiiUaria poselgcriana Haage; Forst. Handb. Cact. ed. 2. 269. 1885. 



High mountains of Mexico and Morelos, and elsewhere in central Mexico. 



Cylindric, 7 to 30 cm. long, 2.5 to 10 cm. in diameter, almost hidden under 

 a dense covering of spines ; axils of tubercles setose ; tubercles 2 to 3 mm. 

 long; spines yellow to red, usually weak, hardly pungent; radial spines about 

 20, 1 cm. long or less ; central spines 7 or 8, 2 cm. long or more ; flowers from 

 the upper part of the plant, purplish, 12 mm. long; inner perianth segments 

 acute. 



69. Neomammillaria densispina (Coulter) Britt. & Rose, Cactaceae 4: 119. 

 1923. 



Cactus densispinus Coulter, Contr. U. S. Nat. Herb. 3: 96. 1894. 



Mammillaria psetidofuscata Quehl, Monatsschr. Kakteenk. 24: 114. 1914. 



San Luis Potosi 



Globose, 6 to 10 cm. in diameter, entirely hidden by the dense covering of 

 spines ; tubercles short and thick, green, not milky ; radial spines 25 or moi*e, 

 slightly spreading, about 1 cm. long, whitish or pale yellow ; central spines 

 5 or 6, longer than the radials, 10 to 12 mm. long, the upper half or third dark 

 brown ; flowers purple without, yellowish within, 1.5 em. long ; seeds obovate, 

 reddish brown, 1 mm. in diameter. 



70. Neomammillaria nunezii Britt. & Rose, Cactaceae 4: 120. 1923. 

 Guerrero, the type from Buenavista de Cuellar. 



Globose to cylindric, 1.5 cm. long, 6 to 8 cm. in diameter ; tubercles closely 

 set, short, terete, setose in their axils ; radial spines white, stiff, about 30, 



