■42 CACTA030US TLANTS. 



Culture. — In so large a genus there must necessarily be some difference 

 of cultural requirements, but this chiefly refers to the temperature, and it 

 the region and elevation at which the plant is found is known there will 

 be comparatively little difficulty in ensuring its success. Most of the 

 true Cereus (the Eucerens of the above table) need a tropical temperature, 

 with similar soil to other genera, though as a rule the strong-growing 

 species can be safely encouraged with a little well-decayed manure if 

 necessary. The trailing sorts need very little rooting material, and some 

 indeed, as C, grandiflorus and its allies, obtain sufficient nutrimen*: by 

 their stem roots alone when upon a suitable wall or trellis. They can all 

 be readily propagated by cuttings of the growth, and even large portions 

 of the stem will root if separated from the parent and placed in dry soil. 

 So readily are roots produced that in some parts of tropical America live 

 fences are formed by placing portions of the stems in closely together, 

 and it is said that they rarely fail. The use of certain species as stocks 

 for grafting other Cactese upon has already been noted, and it need only 

 be added that almost any species is suitable for the purpose provided it 

 be not of too slow growth. 



SELECT SPECIES. 



It will be convenient in considering these to take the true Cerens first. 



Ceeeus peeuvianus, Pfeiffer. — Under various names this Cereus has 

 been known to botanists and grown in European gardens for upwards of 

 150 years, and it is therefore the most familiar example of the cohimnar 

 species. The titles by which it has been designated, such as pentagonus 

 hexagonus, and heptagonus, refer to the number of ridges or angles upon 

 the stem, and owing to these varying considerably the same species in 

 different stages has received the respective names. C. pentagonus of 

 Haworth has been regarded as distinct from C. peruvianus but there 

 appears to be little doubt that in a broad sense all that have been described 

 imder these names are simply variations of one type represented by C. 

 pemvianus, which is a native of many districts in tropical America. There 

 with C. giganteus and other aUied species it forms a remarkable feature, 

 the tall rigid stems being sometimes freely branched in candelabra-like 

 manner, and producing at certain seasons abundance of beautiful flowers. 



In cultivation this Cereus gi-ows rapidly, and soon, if unrestricted, attains 

 a height of from 12 to 20 feet, a few specimens being seen as much as SO feet 

 high. Probably the most remarkable in England are those in Mr. Major's 

 collection at Cromwell House, Croydon, of which an engraving is given in 

 fig. 9, prepared from a photograph very kindly furnished by Mr. Major. The 

 •original plant (the central one in the figure) was bought in Holland in 1852 • 

 but by cutting down the stem at intervals a family of fine specimens has been 

 ■ obtained, some of which are equally as large as the parent. The old stem 



