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The Rainbow Cactus. 



CEREUS CAESPITOSUS. 



pectinatus mainly in its larger and more robust growth, in the ab- 

 sence of central spines and the rigidity of the long radial spines, one 

 fourth to one half inch long. 



Cereus pectinatus Engelmann. — Plant ovate-cylindrical; ribs 

 18 to 23; areolae lanceolate; radial spines 16 to 20, subrecurved, 



pectinated, tips rosy; central 

 spines, 2 to 5, short ; flowers 

 purple with 60 to 70 clusters of 

 10 to 15 rigid spines on the 

 ovary. The flowers are two to 

 three and a half inches across 

 and very fragrant — one flower 

 is said to scent a whole house. 

 The plant is of cespitose growth 

 as shown by the illustration 

 and one cluster will bear a large 

 number of flowers in a single 

 season. Single plants will often 

 bear a dozen or fifteen flowers, 

 and four or five may open in 

 one day. 



Var. armatus Posel. — Ribs 15 to 16 ; radiating spines 16 to 20 

 with a single central spine longer than the rest. This variety is de- 

 scribed from Monterey, Mexico, and is little known. Engelmann 

 was in doubt as to whether it was a form of this species or of C. 

 caespitosus. 



Var. rufispinus is a horticultural variety with beautiful pink 

 spines, otherwise probably not different from the typical form. 



Var. robustus of Sonora and Arizona is another horticultural 

 name for the rainbow cactus, for which Engelmann 's name should 

 receive preference. 



Cereus pectinatus, and C. caespitosus also, are often grafted on 

 Cereus grandiflorus, presenting a rather curious appearance. They 

 are much more beautiful, however, in their natural condition, and 

 there is nothing to be gained by the grafting process except an 

 oddity and an unnatural growth. 



Cereus caespitosus Engelmann. — A near relative to the preced- 

 ing in this small but beautiful plant. One of the most profuse 

 bloomers and in itself a perfect gem, it is not strange that the plant 

 is a general favorite wherever introduced. It will retain vitality for 

 a year without roots or potting. It seldom exceeds six inches in 

 height, but when scarcely an inch high has been known to bear four 

 large purple flowers at a time ! 



