958 CONTRIBUTIONS FEOM THE NATIONAL HERBARIUM. 



5. Thelocactus buekii (Klein) Britt. & Rose, Cactaceae 4: 8. 1923. 

 Echinocactus buekii Klein, Gartenflora 8: 257. 1S59. 



Mexico, the locality not known. 



Stems simple, deep green ; tubercles distinct, somewhat pointed, angled ; 

 spines about 7, reddish, unequal, some of them outwardly curved, the longer 

 ones much elongate ; flowers dark red ; inner perianth segments narrow. 



6. Thelocactus leucacanthus (Zucc.) Britt. & Rose, Cactaceae 4: 8. 1923. 

 Echinocactus leucacanthus Zucc. ; Pfeiff. Enum. Cact. 66. 1837. 



Cereiis tuberosus Pfeiff. Enum. Cact. 102. 1837. 



Cereiis maelenii Pfeiff. Allg. Gartenz. 5: 378. 1837. 



Echinocactus porrectus Lem. Cact. Aliq. Nov. 25. 1838. 



Echinocactus subporrectus Lem. Cact. Aliq. Nov. 25. 1838. 



Echinocactus th&loideus Salm-Dyck, Allg. Gartenz. 18: 396. 1850. 



Central Mexico ; type from Zimapdn, Hidalgo. 



Densely cespitose, short-cylindric, 10 to 15 cm. long; ribs 8 to 13, sometimes 

 spiraled, obtuse, tubercled; radial spines 7 to 20, at first light yellow, in age 

 gray, spreading or recurved, unequal, the longer ones 4 cm. long, more 

 or less annulate; central spines solitary, at first blackish, in age gray, up to 

 5 cm. long ; flowers yellow, 5 cm. long ; inner perianth segments numerous, 

 lanceolate, acute; ovary and flower tube bearing broad imbricate scales. 



Here should perhaps be referred Echinocactus ehrenbergii Pfeiffer (Allg. 

 Gartenz. 6: 275. 1838). 



7. Thelocactus nidulans (Quehl) Britt. & Rose, Cactaceae 4: 9. 1923. 

 Echinocactus nidulans Quehl, Monatsschr. Kakteenk. 21: 119. 1911. 

 Mexico, the range not known. 



Simple, depressed-globose, 10 cm. high, sometimes 20 cm. in diameter, gray, 

 usually glaucous; ribs 20 to 25, rather indistinct, divided into tubercles; 

 spines about 15, all similar, 2 to 6 cm. long; flowers 4 cm. long, yellowish 

 white. 



8. Thelocactus fossulatus (Scheidw.) Britt. & Rose, Cactaceae 4: 10. 1923. 

 Echinocactus fossulatus Scheidw. Allg. Gartenz. 9: 49. 1841. 



San Luis Potosl. 



Globose to much depressed, 10 to 15 cm. in diameter ; ribs usually 13, slightly 

 glaucous, bronzed ; tubercles large, somewhat flabby, more or less compressed, 

 dorsally somewhat angled ; flowering areoles narrow, sometimes extendin;^ 

 forward to the next tubercle; radial spines 4 or 5, unequal, 1 to 3.5 cm. long, 

 brown ; central spine solitary, 3 to 4.5 cm. long, subulate, annulate ; flowers 

 central, nearly white or slightly tinged with pink ; scales on flower tube ovate, 

 their scarious margins slightly ciliate. 



Echinocactus drageanus Moerder (Rev. Hort. 67: 186. 1895) and E. droege- 

 anus Hildmann (Schum. Gesamtb. Kakt. 438. 1898) probably belong here. 



9. Thelocactus tulensis (Poselger) Britt. & Rose, Cactaceae 4: 11. 1923. 

 Echinocactus tulensis Poselger, Allg. Gartenz. 21: 125. 1853. 

 Tamaulipas ; type from Tula. 



Plant simple to abundantly cespitose, globular to short-cylindric, up to 26 

 cm. high ; ribs 8 to 13, strongly tubercled ; radial spines 6 to 8, more or less 

 spreading, 10 to 15 mm. long, brownish ; central spines solitary or sometimes 

 2, 3 cm. long ; flowers 2.5 cm. long, rose-colored ; inner perianth segments linear* 

 oblong, acute. 



