STANDLEY TBEES AND SHRUBS OP MEXICO. 937 



erect or connivent, longer than tlie other 2, sometimes 3 to 4 cm. long, never 

 annulate; flowers 3 to 4 cm. broad, nearly white; inner perianth segments 

 linear-oblong, with an ovate apiculate tip, slightly tinged with lavender, 15 

 mm. long; scales on the ovary broadly ovate, apiculate, scarious. 



9. Echinofossulocactus lamellosus (Dietr.) Britt. & Rose, Cactaceae 3: 113. 



1922. 



Echinocactus lamellosus Dietr. Allg. Gartenz. 15: 177. 1847. 



Hidalgo. 



Subglobose to short-cylindric, more or less depressed at apex ; ribs about 30, 

 strongly flattened, more or less undulate; areoles remote, tomentose when 

 young ; spines 5 or 6, white with brown tips ; flowers tubular, 3.5 to 4 cm. 

 long; inner perianth segments linear to linear-lanceolate, acute. 



10. Echinofossulocactus grandicornis (Lem.) Britt. & Rose, Cactaceae 3: 

 114. 1922. 



EcMnocactus grandicornis Lem. Cact. Hort. Monv. 30. 1839. 



Mexico, the range not known. 



Plants simple, globose to slender-cylindric, 10 cm. high, 5 to 6 cm. in diameter, 

 glaucous-green, the apex hidden by the spines; ribs 34 or 35, much com- 

 pressed, acute, undulate; areoles only a few to each rib, tomentose when 

 young, naked in age ; spines 8 to 11, at first j'ellowish ; upper spines erect, 

 stout, flat, 5 cm. long, the 2 lateral ones not so stout, a little shorter and nearly 

 terete, the other spines slender ; flowers whitish purple. 



11. Echinofossulocactus arrigens (Link) Britt. & Rose, Cactaceae 3: 114. 

 1922. 



EcMnocactus arrigens Link; Dietr. Allg. Gartenz. 8: 161. 1840. 



Echinocactus sphaerocephalus Miihlenpf. Allg. Gartenz. 14: 370. 1846. 



Echinocactus allardtianus Dietr. Allg. Gartenz. 15: 178. 1847. 



Mexico, the range not known. 



Plant simple, deep-seated in the soil, globular, 5 to 7 cm. in diameter, 

 glaucescent, more or less depressed at apex; ribs 24, thin and wavy; spines 

 8 to 11, yellow ; uppermost spine elongate, 2 to 4 cm. long, flattened, brownish ; 

 central spines 2 or 3, more slender and not quite so long as the uppermost 

 one ; radial spines 6 to 8, acicular, usually pale, spreading ; flowers small, 

 2 to 2.5 cm. long; inner perianth segments oblong, apiculate, with deep purple 

 stripe down the center and with pale, nearly white margins. 



The following species have been referred here by some authors : Echino- 

 cactus xiphacanthus Miquel (Linnaea 12: 1. 1838) ; E. ensiferus Lem. (Cact. 

 Aliq. Nov. 26. 1838) ; Echinofossulocactus ensiformis Lawi*ence (Loud. Gard. 

 Mag. 17: 317,, 1841). 



12. Echinocactus violaciflorus (Quehl) Britt. & Rose, Cactaceae 3: 114. 1922. 

 Echinomctus violaciflorus Quehl, Monatsschr. Kakteenk. 22: 102. 1912. 

 Zacatecas (type locality) and Aguascalientes. 



Simple, at first globose, but becoming columnar, 8 to 10 cm. in diameter; 

 ribs about 35, thin, deeply crenate; spines about 7, the 4 or 5 lower ones 

 7 to 12 mm. long, appressed or incurved, white, subulate, the 3 upper spines 

 flattened, 3 to 6 cm. long, ascending and the uppermost ones connivent over 

 the top of the plant ; flowers 2 to 2.5 cm. long ; perianth segments narrow, 

 acuminate, white with violet or purplish stripe down the middle; scales on 

 the ovary more or less imbricate, in 3 or 4 rows, broadly ovate, apiculate 

 with scarious margins. 



