STANDLEY TREES AND SHRUBS OF MEXICO. 955 



Plants solitary or cespitose, globular to cylindric, up to 60 cm. high ; ribs 

 usually 5, sometimes 6, 8, or rarely even 10, very broad, acute, usually covered 

 with white woolly scales but sometimes naked ; spines wanting, at least on old 

 plants ; flowers 4 to 6 cm. long ; outer perianth segments narrow, with brown 

 scarious tips ; inner perianth segments oblong ; scales on ovary and flower tube 

 scarious, imbricate, narrow, often bristly-tipped, with long wool in their axils. 

 ^' Mitra " (San Luis PotosI) ; " birreta de obispo " (Coahuila) ; " bonete ", 

 " pej'ote Cimarron " (Durango). 



2. Astrophytum asterias (Zucc.) Lem. Cact. 50. 1868. 

 Echinocactiis asterias Zucc. Abh. Akad. Wiss. Miinchen 4:-: 13. 1845. 

 Tamaulipas and Nuevo Leon, and elsewhere in northern Mexico. 



Plant much depressed, only 2 to 3 cm. high, about 8 cm. broad ; ribs 8, very 

 low, almost flat on top, the surface bearing numerous depressions, containing 

 tufts of wool ; areoles prominent, circular, felted, 4 to 5 mm. apart, spineless ; 

 flowers 3 cm. long, yellow. " Peyote." 



3. Astrophytum capricorne (Dietr.) Britt. & Rose, Cactaceae 3: 184. 1922. 

 Echinocactvs capricornis Dietr. AUg. Gartenz. 19: 274. 1851. 



Northern Mexico; type from La Rinconada. 



Subglobose or short-cylindric, ?tp to 25 'cm. high; ribs 7 or 8, high, acute; 

 areoles 2 to 3 cm. apart ; spines several, more or less flattened, weak, hardly 

 pungent, brown, 3 to 5 cm. long; flowers 6 to 7 cm. long; outer perianth seg- 

 ments reddish, gradually passing into the lemon-yellow inner ones, spatulate, 

 acute or cuspidate, entire or m.ore or less toothed ; seeds 2.5 mm. broad, shining. 

 " Biznaga de estropajo " (Durango, Patoni). 



4. Astrophytum ornatum (DC.) Weber; Britt. & Rose, Cactaceae 3: 185. 1922. 

 Echinocactiis ornatus DC. M6m. Mus. Hist. Nat. 17: 114. 1828. 

 Echinocactus mirhelii Lem. Cact. Aliq. Nov. 22. 1838. 



Echinocactiis holopterus Miquel, Linnaea 12: 2. 1838. 



Echinocactus tortus Scheidw. Bull. Acad. Brux. 5: 493. 1838. 



Echinocactus ghiesbrechtii Salm-Dyck, AUg. Gartenz. 18: 395. 1850. 



Echinopsis haageana Linke, Wochenschr. Gartn. Pflantz. 1: 86. 1858. 



Hidalgo and Queretaro. 



Subglobose to cylindric, 3 cm. high or more, the surface more or less white- 

 floccose; ribs 8, rather prominent, 2 cm. high or more, acute; areoles 1 to 5 

 cm. apart, felted; spines 5 to 11, subulate, yellow at first, becoming brown, 

 often 3 cm. long; flowers lemon-yellow, 7 to 9 cm. broad; inner perianth 

 segments broadly oblong, with a broad, more or less serrate apex; scales on 

 ovary very narrow. 



38. CACTUS L. Sp. PI. 466. 1753. 



About 18 species are known, natives of tropical America. 

 1. Cactus Salvador (Murillo) Britt. & Rose, Cactaceae 3: 228. 1922. 



Melocactus Salvador Murillo, Circular (about 1897). 



Vicinity of Jalapa, Veracruz. 



Plants simple, globose, 30 to 40 cm. in diameter; ribs 13; radial spines 1 

 to 3, longer and stouter than the radials, those near the center of the plant 

 nearly erect, those on the side somewhat curved downward; cephalium 8 

 cm. in diameter ; flowers rose-pink ; seeds black. 



Two other species of Melocactus have been described from Mexico, M. 

 curvispinus Pfeiff. (Enum. Cact. 46. 1837) and M. delessertianus Lem. (Hort. 

 Univ. 1: 225. 1839), but both are imperfectly known. 



