no THE CACTACEAE. 



Schumann described the group briefly, as follows: 



"Ribs mostly moderately high, laterally compressed, almost like cardboard, very many (. 

 coptonogonus with only 13 to 15); flowers small, like a Mammillaria flower; ovary with scales and 

 glabrous." 



Key to Species. 



Ribs thick at base, triangular in cross-section. 



Ribs 10 to 14 1. E. coptonogonus 



Ribs about 35 2. E. hastatus 



Ribs always numerous, very thin even at base. 



Ribs 100 or more 3. E. multicostatus 



Ribs 25 to 55. 



Some or all of radial spines acicular or setaceous. 

 Radial spines all acicular, white, straight. 

 Flowers greenish yellow. 



Central spines terete 4. E. wippermannii 



Central spines narrow, but flattened 5. E. heter acanthus 



Flowers not greenish yellow. 



Central spines 4 6. E. attains- 



Central spines 3. 



Central spines annulate; apex of plant not depressed 7. -E. Iloydii 



Central spines not annulate; apex of plant umbilicate 8. E. sacatecasensis 



Upper radial spines subulate, some flattened. 

 Spines yellow or white. 



Spines only 5 or 6 9. E. lamellosus 



Spines 8 to 1 1 10, E. grandicornis 



Central and upper spines brownish 11. E. arrigens 



None of the spines acicular. 



Perianth-segments rather short. 



All spines appressed against plant 12. E. violac iflorus 



Some spines erect or porrect. 

 Ribs about 25. 



Four upper spines much elongated 13. E. obvallatus 



Spines all somewhat similar. 



Spines only 5 14. E. pentacanthus 



Spines 10 or more 15. E. crispatits 



Ribs 30 or more. 



Radial spines white 16. E. dichroacanthus 



Radial spines brown. 



Flowers purplish 17. E. anfractuosus 



Flowers yellow. 



Upper and flattened spines 3, rather short, red 18. E. tricuspidalus 



Upper and flattened spines usually 1, rarely 2 19. E. phyllacanthus 



Perianth-segments much elongated and widely spreading or recurved 20. E. lancifer 



_ . , /21. E. gladiolus 



Species not grouped (22. JS. confusus 



1. Echinofossulocactus coptonogonus (Lemaire) Lawrence in Loudon, Gard. Mag. 17: 317. 1841. 



Echinocactus coptonogonus Lemaire, Cact. Aliq. Nov. 23. 1838. 

 Echinocactus coptonogonus major Lemaire, Cact. Gen. Nov. Sp. 87. 1839. 

 Echinofossulocactus coptonogonus major Lawrence in Loudon, Gard. Mag. 17: 317. 1841. 



Simple or perhaps cespitose, globular or a little depressed, 7 to 10 cm. high, glaucous -green; ribs 

 stout, 1.5 cm. high, 10 to 14, acute ; areoles about 2 cm. apart, when young abundantly floccose, but in 

 age naked; spines 3 to 5, stout, a little incurved, the longest 3 cm. long, flattened; flowers 3 cm. long, 

 4 cm. broad; inner perianth-segments numerous, linear-oblong, acute, purple with white margins; 

 ovary brownish violet, bearing thin scales. 



Type locality: Mexico. 



Distribution : Mexico, near San Luis Potosi and Pachuca, according to Schumann ; the 

 plant found at the latter locality is probably to be referred elsewhere. 



This species is very abundant about San Luis Potosi from which place we have received 

 considerable material from Orcutt and Palmer. It does not do well in cultivation. Only 

 one plant is now alive in our collection and this has never flowered. 



Echinocactus interruptus Scheidweiler (Cact. Hort. Dyck. 1849. 29. 1850) was referred 

 here but never published. It was also used by Pfeiffer (Enum. Cact. 65. 1837) as a syno- 

 nym of E. exsculptus. 



