STANDLEY TREES AND SHRUBS OF MEXICO. 935 



Upper radial spines subulate, some of them flattened. 

 Spines all yellow or white. 



Spines 5 or 6 9. E. lamellosus. 



Spines 8 to 11 10. E. grandicornis. 



Spines partly (central and upper ones) brownish 11. E. arrigens. 



Radial spines never acicular. 



Perianth segments much elongate and widely spreading or recurved. 



20, E. lancifer. 

 Perianth segments rather short. 



Spines all appressed against the plant 12. E. violaciflorus. 



Spines partly erect or porrect. 

 Ribs about 25. 



Spines partly (four upper ones) much elongate. 



13, E. obvallatus. 

 Spines all similar. 



Spines 5 14. E, pentacanthus. 



Spines 10 or more 15. E. crispatus. 



Ribs 30 or more. 



Radial spines white 16. E, dichroacantlius. 



Radial spines brown. 



Flowers purplish 17, E, anfractuosus. 



Flowers yellow. 



Upper and flattened spines 3, rather short, red. 



18. E. tricuspidatus. 

 Upper and flattened spines usually 1, rarely 2. 



19. E. phyllacanthus. 



1. Echinofossulocactus coptonogonus (Lem.) Lawrence; Loud. Gard. Mag. 



17: 317, 1841, 



Echinocactus coptonogonus Lem. Cact. Aliq. Nov. 23. 1838. 



Reported from San Luis Potosi and Hidalgo. 



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 

 wliite margins ; ovary brownish violet, bearing thin scales. 



2. Echinofossulocactus hastatus (Hopffer) Britt. «& Rose, Cactaceae 3: 



111. 1922. 



Echinocactus hastatus Hopffer; Schum. Gesamtb. Kalit. 376. 1898. 



Hidalgo. 



Simple, depressed-globose, 10 cm. higli, 12 cm. in diameter ; ribs 35, triangu- 

 lar in section, light green, somewhat crenato ; radial spines 5 or 6, very short, 

 straight, yellow, the upper ones flattened, often 3 cm. long ; central spine soli- 

 tary, 4 cm. long, porrect; flowers white (the largest in this genus) ; fruit be- 

 coming dry ; seeds obovate, 1.5 mm. long, brownish gray, shining, finely 

 punctate. 



3. Echinofossulocactus multicostatus (Hildemann) Britt. & Rose, Cactaceae 



3: 111. 1922. 

 Echinocactus multicostatus Hildemann; Mathsson, Gartenflora 39: 465. 1890. 

 Eastern Mexico ; type said to have come from Saltillo, Coahuila. 

 Simple, usually globose, but sometimes depressed, 6 to 10 cm. in diameter ; 

 ribs 100 or more, very thin, wavy, each bearing only a few areoles ; areoles 



