STANDLEY TEEES AND SHRUBS OF MEXICO. 967 



Plant body simple, cylindric, 30 cm. high, 12 to 15 cm. in diameter; axils 

 of tubercles bearing white wool, the groove with 1 or 2 red glands ; tubercles 

 elongate, up to 25 mm. long, spreading, somewhat 4-angled but with broad 

 bases ; radial spines 8, spreading, rigid, horn-colored with black tips, 10 to 12 

 mm. long ; central spines 1 or 2, stouter than the radials, brownish, 25 mm. 

 long ; flowers about 6 cm. broad, straw-colored ; perianth segments linear-ob- 

 long, obtuse. 



11. Coryphantha exsudans (Zucc.) Lem. ; Britt. & Rose, Cactaceae 4: 31. 1923. 

 MammiUaria exsudmis Zucc. ; Pfeiff. Enum. Cact. 15. 1837. 

 Mammillaria hrevimamma Zucc. ; Pfeiff. Enum. Cact. 34. 1837. 

 MammiUaria glanduligera Otto & Dietr. Allg. Gartenz. 16: 298. 1848. 

 Mammillaria asterias Cels; Salm-Dyck, Cact. Hort. Dyck. 1849. 129. 1850. 

 Mexico ; type collected between Ixmiquilpan and Zimapan, Hidalgo. 

 Subcylindric, 4 cm. in diameter ; tubercles dull green, thick, ovate ; glands 



in the axils of the tubercles pale yellow; spine areoles somewhat tomentose, 

 becoming naked; radial spines 6 or 7, 6 to 10 mm. long, slender, straight, 

 spreading, yellow; central spines 1, erect, yellow, but brown at tip, perhaps 

 hooked ; flowers yellow. 



12. Coryphantha erecta Lem. Cact. 34. 1868. 



MammiUaria erecta Lem.; Pfeiff. Allg. Gartenz. 5: 370. 1837. 



MammiUaria ceratocentra Berg, Allg. Gartenz. 8: 130. 1840. 



Hildalgo. 



Plant body cylindric, yellowish green ; axils of young tubercles white-woolly ; 

 tubercles obliquely conic, somewhat rhombiform at base; radial spines 8 to 

 14, subulate, ascending, yellowish ; central spines 2, the upper one short, the 

 lower curved ; flowers large, yellow ; perianth segments very narrow. 



13. Coryphantha elephantidens Lem. Cact. 35. 1868. 

 MammiUaria elepliantidens Lem. Cact. Aliq. Nov. 1. 1838. 

 Central Mexico. 



Simple, subglaucous, up to 14 cm. high and 19 cm. broad ; tubercles very 

 large, somewhat flattened, obtuse, 4 to 5 cm. long, densely woolly in their 

 axils; areoles elliptic, when young woolly, in age naked; spines 8, all radial, 

 somewhat unequal, subulate, the longest about 2 cm. long, spreading, when 

 young brownish with yellowish bases, black at apex; flowers, rose-colored, 11 

 cm. broad; perianth segments numerous, narrowly oblong, apiculate. 



14. Coryphantha bumamma (Ehrenb.) Britt. & Rose, Cactaceae 4: 33. 1923. 

 Mammillaria bumamma Ehrenb. Allg. Gartenz. 17: 243. 1849. 



Morelos and Guerrero. , 



Globular or somewhat depressed ; tubercles few, very large, rounded at 

 apex, bluish green, very woolly in their axils when young but glabrate in age ; 

 spines 5 to 8, subulate, grayish brown, more or less recurved, 2 cm. long or 

 more, all radial; flower yellow, 5 to 6 cm. broad; inner perianth segments 

 narrowly oblong, obtuse or retuse. 



15. Coryphantha robustispina (Schott) Britt. & Rose, Cactaceae 4: 33. 1923. 

 Mammillaria rohustispina Schott; Engelm. Proc. Amer. Acad. 3: 265. 1856. 

 Mammillaria hrownii Tourney, Bot. Gaz. 23: 253. 1896. 



Sonora, the type from the south side of the Babuquibari Mountains. Arizona. 



Stems simple or. clustered, globular or a little longer than thick, broad, 5 to 

 15 cm. high, densely armed and almost hidden by the spines; tubercles 2.5 

 to 2.8 cm. long, arranged in 13 somewhat spiraled rows, fleshy, in age thickly 

 set one against the other, becoming more or less dorsally flattened, pale grayish 

 green, narrowly grooved; radial spines 12 to 15, the 3 lower ones very stout, 



