196 THE CACTACEAE. 
Echinocactus ottonis paraguayensis Heese, Gartenwelt 9: 266. 1905. 
Echinocactus ottonis uruguayus Arechavaleta, Anal. Mus. Nac. Montevideo 5: 213. 1905. 
Echinocactus arechavaletai Spegazzini, Anal. Mus. Nac. Buenos Aires IIT. 4: 496. 1905. 
Echinocactus spegazzinii Gtirke, Monatsschr. Kakteenk. 15: 110. 1905. 
Echinocactus ottonis brasiliensis Haage jr., Monatsschr. Kakteenk. 24: 41. 1914. 
Simple or cespitose, globular or somewhat depressed, more or less glossy green, 5 to 6 cm. in 
diameter; ribs 10, broad and rounded below; areoles few, usually distant, 1 cm. apart or more, small, 
circular; spines acicular, brown, 1 cm. long or less; flowers from the uppermost areoles, one or more 
appearing at a time, 5 to 6 cm. long, bright yellow; perianth-segments linear-oblong, acute; sta- 
mens about half the length of the perianth-segments; style yellow; stigma-lobes red; axils of scales 
filled with long brown wool and brown bristles. 
Typelocality: Supposed to be Mexico, but the species was described from a garden plant. 
Distribution: Southern Brazil, Uruguay, and adjacent parts of Argentina. 
The varietal name, Echinocactus ottonis paraguayensis, is usually credited to Schumann 
who used it in 1900 (Monatsschr. Kakteenk. 10: 179). The name Cereus ottonis appears 
in Pfeiffer’s Enumeratio (47. 1837) as a syn- 
onym of Echinocactus ottonis, but it does not 
occur thus where Pfeiffer cites it (Nov. Act. Nat. 
Cur. 16: 316. 1828), but as Cactus (Cereus) 
ottonts. 
The following varieties are-sometimes met 
with: E. ottonis brasiliensis (Monatsschr. Kak- 
teenk. 18: 48. 1908), pfeifferi Monville (Salm- 
Fics. 210 and 211.—Malacocarpus ottonis. 
Dyck, Cact. Hort. Dyck. 1844. 19. 1845), and minor (Forster, Handb. Cact. 302. 1846), 
and Echinocactus muricatus hortatanit (Labouret, Monogr. Cact. 232. 1853). 
A hybrid has been produced with this species and a plant called Echinopsis zuccarinit. 
Illustrations: Cact. Journ. 1: 43, 54; Monatsschr. Kakteenk. 12: 158; 29: 125; Martius, 
Fl. Bras. 4°: pl. 51, f. 3; Edwards’s Bot. Reg. 24: pl. 42; Rev. Hort. 1861: 270. f. 62; Curtis’s 
Bot. Mag. 58: pl. 3107; Link and Otto, Icon. Pl. Rar. pl. 16; De Laet, Cat. Gén. f. 11; 
Millers Deutsche Gart. Zeit. 25: 474. f. 6, No. 17; Riimpler, Sukkulenten 179. f. 98, as 
Echinocactus ottonis; Anal. Mus. Nac. Montevideo s: pl. 12; De Laet, Cat. Gén. f. 4; Tri- 
bune Hort. 4: pl. 140, as Echinocactus ottonis tenuispinus; Link and Otto, Icon. Pl. Rar. 
pl. 15, as E. tortuosus; Nov. Act. Nat. Cur. 16: pl. 15, as Cactus ottonis; Verh. Ver. Beford. 
3: pl. 19, f. 1, 2, as Melocactus tenuispinus; Anal. Mus. Nac. Montevideo 5: pl. 13, as E. 
ottonts uruguayus, Gartenwelt 9: 267; Schelle, Handb. Kakteenk. 182. f. 116, as Echinocactus 
ottonts paraguayensis; Anal. Mus. Nac. Montevideo 5: pl. 11, as Echinocactus arechavaletat; 
Curtis's Bot. Mag. 68: pl. 3963, as Echinocactus tenuispinus; Dict. Hort. Bois 465. f. 323; 
as Echinocactus tenuispinus ottonis; Karsten, Deutsche FI. 887. f. 501, No. 12; ed. 2. 2: 456. 
f. 605, No, 12, as Echinocactus tenuissimus. San 
