218 



THE CACTACEAE. 



3. Discocactus heptacanthus (Rodrigues). 



Malacocarpus heptacanthus Rodrigues, PI. Mattogr. 29. 1898. 



Globose or slightly depressed, usually solitary, 8 to 10 em. in diameter; ribs 10 or n, very 

 broad, broken up into a few large, rounded tubercles; areoles circular, at first tomentose; spines 

 usually 7, all radial, stout, recurved; cephalium small but definite, white, containing many erect 

 bristles; flowers and fruit unknown. 



Type locality: Serra da Chapada, near Cuyaba, Matto-Grosso, Brazil. 



Distribution: Known only from the type locality. 



Schumann in his Nachtrage referred this to Echinocactus alteolens, but it is certainly 

 different from that species. We have not seen the type of this species, which has not been 

 preserved; but we have seen Mr. F. C. Hoehne's specimen, which came from Rodrigues's 

 locality, Cuyaba, Matto-Grosso, and we have a photograph of it. 



Illustration: Rodrigues, PI. Mattogr. pi. 11, as Malacocarpus heptacanthus. 



Figure 232 is a copy of the illustration cited above. 



4. Discocactus alteolens Lemaire in Dietrich, Allg. Gartenz. 14: 202. 1846. 



Discocactus tricornis Monville in Pfeiffer, Abbild. Beschr. Cact. 2: pi. 28. 1846-1850. 

 Echinocactus alteolens Schumann in Martius, Fl. Bras. 4 2 : 246. 1890. 

 Cactus alteolens Kuntze, Deutsch. Bot. Monatsschr. 21: 173. i93- 



Plant solitary, broader than high, dull gray, crowned by a broad cephalium; ribs 9 or 10, broad 

 at base, low ; radial spines 5 or 6, the 3 upper ones very short, ascending ; central spines none or rarely 



Fig. 232. Discocactus heptacanthus. 



Fig. 233. Discocactus placentiformis. 



solitary and porrect; flowers salverform; tube slender, bearing slender scales with naked axils; inner 

 perianth-segments white, numerous, obtuse; ovary naked, glabrous. 



Type locality: Not cited. 



Distribution: Doubtless eastern central Brazil. 

 This species is known to us from description and illustration only. 

 Echinocactus tricornis Monville is given by A. Dietrich (Allg. Gartenz. 14: 203. 1846) 

 as a synonym. 



Illustration: Pfeiffer, Abbild. Beschr. Cact. 2: pi. 28, as Discocactus tricornis. 

 Figure 229 is a reproduction of the illustration here cited. 



5. Discocactus zehntneri sp. nov. 



Small globose plants, 5 to 7 cm. in diameter, entirely covered by the numerous interlocking spines ; 

 spines 12 to 14 in a cluster, gray to nearly white at least when old, slender, acicular, curved back- 

 ward, 1.5 to 2.5 cm. long; central spine usually solitary, similar to the radials ; cephalium small, made 



