I2 4 



TIIK CACTACKAE. 



As understood by us this species varies greatly in the relative thickness of its branches, 

 in armament, and in the size of its flowers. Its geographical range is, in our conception, 

 greater than that of most cacti. 



Cereus l>n.\\inicnsis rauiosus (Salm-Dyck in Walpers, Repert. Bot. 2:277. J 843) is 

 published only as a synonym. Ccrcns arciiatux Zuccarini (Monatsschr. Kakteenk. 14:55. 

 1904) from its description is of this relationship. It was originally collected at Totolapa, 

 Mexico, by Zuccarini. 



Cereus bajtuh'iisis \Verckle (Monatsschr. Kakteenk. 15: 166. 1905) was never described 

 but belongs here. Cereus quadrangularis Haworth (Syn. PI. Succ. 181. 1812; C. ti-i^nin^ 

 quadrangidaris Pfeiffer, Enum. Cact. 118. 1837; Cactus quadrangularis Loudon, Encycl. 

 PI. 412. f. 6876. 1829) may belong here, but Pfeiffer referred it with a question to Ccrcus 

 caripcnsis De Candolle (Prodr. 3:467. 1828; Cactus c<.iripcnsis Humboldt, Bonpland, and 

 Kunth, Nov. Gen. et v Sp. 6: 66. 1823), but this species was referred by Schumann to the 

 genus Rhipsalis. 





IMC.. 184. Acanthocereus penta^onus in cactus plantation of Charles Deering at Buena Vista, Florida, May 1918. 



Cereus undulatus Pfeiffer (Enum. Cact. 107. 1837), based on a specimen in the Dresden 

 Garden, is usually referred to Cereus acutangulus, but was not described by Pfeiffer at the 

 place here cited. 



A specimen in the Berlin Garden also was called Cereus undulatus by D. Dietrich (Syn. 

 PI. 3: 104. 1843) and described, but should be referred elsewhere. It is of quite different 

 relationship, being very slender, dull green, lo-ribbed. The flowers are large, 12.5 cm. in 

 diameter, white. Its native habitat is unknown. 



Illustrations: Cact. Journ. i: 125; Cact. Mex. Bound, pi. 60, f. 5, 6, all these as Ccrcitx 

 ri<il>ilis; Monatsschr. Kakteenk. 13: 158; Rev. Hort. Beige 40: after p. 184; Tribune 

 Hort. 4: pi. 140, as Cereus baxaniensis. 



Plate xvi, figure i, shows a flower and part of a joint of a plant sent from the Berlin 

 Botanic Garden to the New York Botanical Garden. Figure 182 is from a photograph 



