2 2 THE CACTACEAE. 



S to 12, brown; flower 10 to 12 cm. long, the tube 5 to 6 cm. long; outer perianth-segments pinkish; 

 inner perianth-segments white; ovary small, bearing a few very small scales, these broader than 

 long, with minute brown chartaceous tips; fruit globular, 4 to 5 cm. in diameter. 



Type locality: Carthagene.* 



Distribution: Brazil northern Argentina and Paraguay. 



This is one of the best flowering species we have in cultivation. The flowers open at 

 night and appear more or less abundantly from April to September. 



The species was named for William Spencer Cavendish, Duke of Devonshire, who 

 had a magnificent collection of plants at Chatsworth. 



Cereus anguiniformis (Weingart, Monatsschr. Kakteenk. 18:6. 1908) and C. saxicola 

 anguinijormis Riccobono (Boll. R. Ort. Bot. Palermo 8: 252. 1909) probably belong here. 



We have referred here Cereus euchlorus, which originally came from Sao Paulo, Brazil. 

 We have specimens growing which were obtained under this name from M. Simon, of St. 

 Ouen, Paris, in 1901. 



Fig. 20. — Monvillea cavendish 



Fig. 21. — Monvillea insularis. X0.5. 



Botanists have been much in doubt as to the relationship of this species. Schumann 

 in his Monograph refers it along with Cereus striatus (now Wilcoxia) to his series Tenuiores. 

 In his Nachtrage, published in 1903, he places it with Cereus obtusangulus (now Zygocactus) 

 in his series Anomali, but in his Keys, published about the same time, he again has it in 

 the series Tenuiores. Berger places it in his subgenus Piptanthocereus, while Riccobono has 

 recently transferred it to his genus Eriocereus. 



Dr. Schumann discusses Cereus lauterbachii Schumann (Bull. Herb. Boiss. II. 3: 250. 

 1903) in connection with this species, but does not point out how they differ. 



Both the names Cereus cavendishii and C. paxtonianus were in general use until Schu- 

 mann in 1897 suggested that the plants are the same. Sir Joseph Hooker in 1S99 united 

 them definitely under the name of Cereus paxtonianus. 



Illustrations: Monatsschr. Kakteenk. 19: 77, as Cereus saxicola; Monatsschr. Kak- 

 teenk. 13: 12, as Cereus rhodoleucanthus ; Curtis's Bot. Mag. 125: pi. 7648, as Cereus pax- 

 tonianus. 



*When first published it was stated that the species came from "Carthagene. 1 

 America, possibly Brazil, while Morong collected it in central Paraguay. 



Schumann says probably South 



