REVISION OF THE GENUS CEREUS MILL. 83 



Cereus Kerberi K. Sch. from Mexico is stated to have 

 flowers of the form of Cereus flagelliformis Mill. Cer- 

 tainly it does not belong to Aporocactus, and perhaps 

 it is a Eucereus of the subsection Reliocereus, to judge 

 from the quadrangular stems. 



These small and graceful plants with their slender, 

 dependent stems are very showy when well grown and in 

 full flower. 



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There remain a great number of species of Cereus and 

 "Pilocereus" of which the systematic position is still 

 quite uncertain, as little or nothing is known about their 

 flowers and fruit. I refrain from giving a list of them, 

 as it would needlessly lengthen this paper. 



Species to be excluded : 



Cereus obtusangulus K. Sch. inFlor. Brasil. 198; Monogr. Cact. 127 



Epiphyllum obtusangulum G. A. Lindberg, ex K. Sch. 1. c. 



This very strange little plant, still rare in cultivation, 

 cannot be considered either a Cereus or an Epiphyllum. 

 But no doubt it is much more nearly allied to the latter 

 than to the former genus. Schumann brought it into 

 Cereus on account of its round and ribbed stems, but there 

 exists no Cereus of a similar articulated growth ; only with 

 Rhipsalis and Epiphyllum can it be compared. The plant 

 resembles somewhat a minute Platyopuntia. The joints 

 are slightly flattened and have numerous little prominent 

 areoles distributed spirally all over the surface. In this it 

 differs greatly from Epiphyllum, with which it agrees in 

 all the characters of the flowers, the angular nearly alate 

 ovary and especially in the inner stamens being united at 

 the base into a small incurved membrane. Also, the fruit 



mor 



Epiphyll 



The flowers rise from the top of the joints as in Ephi- 

 phyllum . The plant is best considered as generically dif- 





