THELOCACTUS. 1 3 



Illustrations: Knippel, Kakteen pi. 7, in part; Schelle, Handb. Kakteenk. 144. f. 70, 

 as Echinocactus heterochronius ; Diet. Gard. Nicholson 4: 540. f. 23 ; Suppl. 336. f. 359; Schu- 

 mann, Gesamtb. Kakteen 328. f . 57 ; Garden 2:521; Monatsschr. Kakteenk. 30 : 53 ; Schelle, 

 Handb. Kakteenk. 155. f. 82; Watson, Cact. Cult. 117. f. 43, as Echinocactus pottsii. 



PUBLISHED SPECIES, POSSIBLY OF THIS RELATIONSHIP. 

 Echinocactus conothelos Regel and Klein, Ind. Sem. Hort. Petrop. i860: 48. i860. 



Ovoid to subcylindric, 10 cm. high, 7.5 cm. in diameter, grayish green; ribs somewhat spiraled, 

 somewhat tubercled at base, the lower tubercles 12 to 20 mm. long; upper areoles oblique, white- 

 tomentose; radial spines 14 to 16, white, spreading to recurved, 8 to 10 mm. long; central spines 

 2 to 4, erect or a little spreading and recurved, stouter and longer than the radials, 13 to 34 mm. 

 long; flowers and fruit unknown. 



Type locality: Near Tanquicillos and Jaumave, Mexico. 



This plant was collected by Karwinsky and is known only from his collection. The 

 authors refer the species to Salm-Dyck's section of the Theloidei, which, however, is a 

 very diverse group containing representatives of several genera. Schumann was unable to 

 place the species ; it may be related to some species of Thelocactiis . 



Echinocactus hexaedrus Scheidweiler, Btdl. Acad. Sci. Brux. 6: 89. 1839. 



Globose to oblong-ovate, glaucous; ribs 18, tuberculate; tubercles 6-angled, gibbous below 

 areoles; areoles oblong, lanate; spines 13, white with purplish bases; lowermost spine longest; central 

 spines 2, either straight or recurved; flowers and fruit unknown. 



Type locality: San Luis Potosi. 



Echinocactus saussieri Weber, Diet. Hort. Bois 468. 1896. 



Depressed-globose, 15 to 20 cm. in diameter; ribs spiraled, strongly tubercled; radial spines 9, 

 grayish white, 15 mm. long; central spines 4, acicular, 3 to 4 cm. long; flowers purplish, 4 cm in 

 diameter; inner perianth-segments lanceolate; stamens and style yellow. 



Type locality: Matehuala, state of San Luis Potosi, Mexico. 



We know this species from the brief description only and are unable to determine its 

 relationship. 



Echinocactus smiThii Muhlenpfordt in Otto and Dietrich, Allg. Gartenz. 14: 370. 1846. 



Simple, globose to cylindric, 7 cm. in diameter; ribs 21, often spiraled, strongly tubercled, glau- 

 cous; radial spines 20 to 27, setaceous, white, 16 mm. long; central spines 4, the upper one flattened, 

 white with brown or black tips; flowers reddish, 3.5 cm. long; fruit globular, 8 mm. in diameter; 

 seed nearly globular, flattened at the hilum. 



Type locality: San Luis Potosi. 



We know this species from description only and are unable to assign it to any genus. 



Echinocactus vargasii Regel and Klein, Ind. Sem. Hort. Petrop. i860: 48. i860. 



Globose, 5 cm. high, 6 cm. in diameter; tubercles rather large, somewhat angled, arranged in 

 spirals; radial spines 5 or 6, terete, subulate, brownish, 2 to 6 mm. long; central spine i, erect, 12 

 mm. long; flowers and fruit unknown. 



Type locality: Mexico, near Rio Blanco. 



Schumann did not know this plant nor do we, but to us it suggests a Thelocactus. The 

 authors of the species compared it with Echinocactus poselgerianus, now referred to Cory- 

 phantha, and with E. phymatothelos. 



