960 CONTRIBUTIONS FEOM THE NATIONAL HERBARIUM. 



compressed-globose, dull-colored, thin-walled, becoming papery, dry, with few 

 scales or none; seeds globose, black, dull, tuberculate-roughened, with a large 

 white basal scar. 

 One other species occurs in Texas. 



Plants small, 3 cm. or less in diameter ; central spines sometimes wanting. 



1. N. pilispina. 

 Plants larger; central spines always present. 



Central spines curved or hooked 2. N. clavata. 



Central spines all straight. 

 Central spine solitary. 



Central spine stiff, porrect 3. N". horripila. 



Central spine weak, ascending or connivent 4. N. beguinii. 



Central spines several. 



Spines white, or sometimes dark above 5. N. ceratites. 



Spines, at least the central ones or part of them, black 6. N. conoidea. 



1. Neolloydia pilispina (Purpus) Britt. & Rose, Cactaceae 4: 14. 1923. 

 Mammillaria pilispina Purpus, Monatsschr. Kakteenk. 22: 150. 1912. 

 San Luis PotosI ; type from Minas de San Rafael. 



Plants cespitose, about 3 cm. in diameter; ribs indistinct, of very definite, 

 somewhat angled tubercles; young spine areoles clothed with abundant long 

 white wool covering the top of the plant ; radial spines 6 or '7. 5 to 6 mm. 

 long, weak and spreading the upper ones longer and connivent over the top of 

 the plant, 2 cm. long or more, white with blackish tips ; central spines often 

 wanting, sometimes one; flowers 1.5 to 2 cm. long, purplish; outer perianth 

 segments brownish. 



2. Neolloydia clavata (Scheidw.) Britt. & Rose, Cactaceae 4: 15. 1923. 

 MammUlaria clavata Scheidw. Bull. Acad. Brux. 5: 494. 1838. 

 Mammillaria stipitata Scheidw. Bull. Acad. Brux. 5: 495. 1838. 

 Mammillaria rhaphidacantha Lera. Cact. Hort. Monv. 34. 1839. 

 Mammillaria ancistracantha Lem. Cact. Hort. Monv. 36. 1839. 



? Mammillaria potosiana Jacobi, Allg. Gartenz. 24: 92. 1856. 



Mammillaria sulcoglandulifera Jacobi, Allg. Gartenz. 24: 92. 1856. 



ICactus hninneus Coulter, Contr. U. S. Nat. Herb. 3: 117. 1894. 



ICactus macxiUtus Coulter, Contr. U. S. Nat. Herb. 3: 117. 1894. 



Mammillaria radicantissima Quehl, Monatsschr. Kakteenk. 22:_ 164. 1912. 



San Luis PotosI. 



Plants simple, elongate, cylindric, 10 to 15 cm. high, dark bluish green ; 

 tubercles in rows of 5, 8, and 13, conic, grooved above, the axils when young 

 bearing short white wool; glands in the groove 1 to several, large, red; 

 radial spines 6 to 12, with reddish or black tips ; central spine 1, somewhat 

 longer than the radials, curved or even hooked ; flowers small for the 

 genus, about 2 cm. long; outer perianth segments linear, acute, entire, with 

 broad brownish midrib, the inner ones linear, entire, narrow, creamy white. 



3. Neolloydia horripila (Lem.) Britt. & Rose, Cactaceae 4: 16. 1923. 

 Mammillaria horripila Lem. Cact. Aliq. Nov. 7. 1838. 



Hidalgo. 



Simple or somewhat cespitose, globular to short-cylindric, 10 to 12 era. 

 high ; tubercles glaucous, prominent, rounded at apex ; radial spines 8 to 

 10, acicular, spreading, 15 mm. long, grayish ; central spines solitary, straight, 

 a little longer than the radials ; flowers deep purple, 3 cm. long ; inner 

 perianth segments narrowly oblong, acute. 



