188 THE CACTACEAE. 
Kery To SPECIES—continued. 
Central spines definitely longer than the radials. 
Spines strongly curved........... 0... cece eee eee eee ee ee ee eee 18, M. langsdor fit 
Spines straight... 0.0.0.0... ec eee eee te enaes 19. mammulosus 
Inner perianth-segments about 1 cm. long.....................000002++ 20. tslayensis 
DD. Flowers salmon or red. . 
Ribs about 13, obtuse; flowers salmon................ 0.000. ce eee ee eeeee 21, strausianus 
Ribs 30 or more, acutish; flowers red. .... 0.0... eee eee eee 22. haselbergit 
maassit 
CC. Spines elongated, the central ones 1.5 to 7 cm. long, curved; flowers orange-red... 23. 
BB. Areoles of ovary and flower-tube with tufts of short hairs. 
Spines stout, subulate..... 0.0... eee eee ee eee nee e nee 24. M. tuberisulcatus 
Spines slender, acicular. , 
Spines long, much curved..... 2.0.0.0... cece ce nee ee 25. curvispinus — 
Spines short, nearly straight.... 0... 0.0... 0. eee eee eee eee e eens 26. mammillariotdes 
AA. Plants becoming slender-cylindric and much elongated.....................0005- ma leninghausit 
: ; 28. raessnert 
AAA. Species not grouped ........... 00. cece cece ence cnet eeentenenes \29. M. escayachensts 
S 1. Malacocarpus tephracanthus (Link and Otto) Schumann, FI. Bras. 42: 243. 1890. 
Echinocactus tephracanthus Link and Otto, Verh. Ver. Beférd. Gartenb. 3: 422. 1827. 
Echinocactus acuatus* Link and Otto, Verh. Ver. Beférd. Gartenb. 3: 424. 1827. 
Echinocactus sellowit Link and Otto, Verh. Ver. Beférd. Gartenb. 3: 425. 1827. 
Melocactus tephracanthus Link and Otto, Verh. Ver. Beférd. Gartenb. 3: pl. 16, f. 2. 1827. 
Melocactus sellowii Link and Otto, Verh. Ver. Beford. Gartenb. 3: pl. 22. 1827. 
Melocactus acuatus Link and Otto, Verh. Ver. Beford. Gartenb. 3: pl. 23. 1827. 
“-Echinocactus sellowianus Pfeiffer, Enum. Cact. 55. 1837. 
Echinocactus sessiliflorus Mackie in Curtis’s Bot. Mag. 64: pl. 3569. 1837. 
Echinocactus tetracanthus Lemaire, Cact. Alig. Nov. 15. 1838. 
Echinocactus courantit Lemaire, Cact. Alig. Nov. 20. 1838. 
Echinocactus sessiliflorus pallidus Monville in Lemaire, Cact. Gen. Nov. Sp. 88. 1839. 
Echinocactus sessiliflorus tetracanthus Monville in Lemaire, Cact. Gen. Nov. Sp. 88. 1839. 
Cereus tephracanthus Steudel, Nom. ed. 2. 1: 336. 1840. 
Malacocarpus sellowianus Salm-Dyck, Cact. Hort. Dyck. 1849. 25. 1850. 
Malacocarpus sellowianus tetracanthus Salm-Dyck, Cact. Hort. Dyck. 1849. 25. 1850. 
2 Malacocarpus courantii Salm-Dyck, Cact. Hort. Dyck. 1849. 25. 1850. 
Echinocactus tephracanthus spinosior Labouret, Monogr. Cact. I7I. 1853. 
Echinocactus courantii spinosior Monville in Labouret, Monogr. Cact. 171. 1853. 
Echinocactus sellowianus tetracanthus Labouret, Monogr. Cact. 172. 1853. 
Malacocarpus martinii Riimpler in Férster, Handb. Cact. ed. 2. 454. 1885. 
Malacocarpus sellowii Schumann, FI. Bras. 4°: 238. 1890. 
Malacocarpus sellowii tetracanthus Schumann, FI. Bras. 47: 239. 1890. 
Malacocarpus tetracanthus Meyer, Monatsschr. Kakteenk. 4: 143. 1894. 
Echinocactus sellowii martinii Schumann, Gesamtb. Kakteen 297. 1898. 
Echinocactus acuatus sellowii Spegazzini, Anal. Mus. Nac. Buenos Aires III. 4: 494. 1905. 
Echinocactus acuatus tetracanthus Spegazzini, Anal. Mus. Nac. Buenos Aires III. 4: 494. 1905. 
Echinocactus sellowii macrocanthus Arechavaleta, Anal. Mus. Nac. Montevideo 5: 230. 1905. 
Echinocactus sellowii macrogonus Arechavaleta, Anal. Mus. Nac. Montevideo 5: 232. 1905. 
Echinocactus sellowii acutatus Arechavaleta, Anal. Mus. Nac. Montevideo 5: 234. 1905. 
Echinocactus sellowii turbinatus Arechavaleta, Anal. Mus. Nac. Montevideo 5: 235. 1605. 
Echinocactus fricii Arechavaleta, Anal. Mus. Nac. Montevideo 5: 244. 1905. 
Echinocactus pauctareolatus Arechavaleta, Anal. Mus. Nac. Montevideo 5: 246. 1905. 
Echinocactus sellowii courantii Giirke, Monatsschr. Kakteenk. 18: 149. 1908. 
Echinocactus sellowii typicus Giirke, Monatsschr. Kakteenk. 18: 149. 1908. 
Simple, globular or somewhat depressed, up to 15 cm. in diameter, woolly at apex; ribs 18 to 22, 
acute, rather high, hardly undulate on the margin, light green; areoles 1.5 to 2 cm. apart; spines 4 to 
6, straight or curved backward, the longest 2 cm. long; flowers from the woolly apex of the plant, 
4 to 4.5 cm. long, broader than long when fully expanded; perianth-segments yellow, narrowly ob- 
long, mucronate-tipped; stamens and style slightly exserted; stigma-lobes red; perianth deciduous; 
fruit small, 1 cm. long, purple, fleshy, scaly; scales ovate, bearing hairs and bristles in their axils; 
seeds black, 1 mm. long. 
Type locality: ‘‘Rio Grande,” perhaps better, Rio Grande do Sul, Brazil. 
Distribution: Brazil, Argentina, and Uruguay. 
Walpers (Repert. Bot. 2: 275. 1843) referred Echinocactus acuatus spinosior Lemaire to 
E. courantii. This variety was not described, however, until 1839 when Lemaire (Cact. 
Gen. Nov. Sp. 87. 1839) assigned it to Monville and referred to it, as a synonym, Echino- 
cactus suberinaceus Lemaire. 
*The specific name was originally given by Link and Otto as above, but Schumann changed it, writing both 
Echinocactus acutatus and Melocactus acutatus. Don (Gen. Syst. 3: 163. 183 4) writes the name E. arcuatus. 
