Cjilitite of 'Ne\umh\um speciosum. 513 



Our knowledge of the numerous group of the flat-branched 

 Opiintiae is much too limited at present to enable us to determine 

 the species ; but we hope, in time, to establish a system, and 

 particularly for those gardens where this tribe of plants is culti- 

 vated. What a difference between an Opuntia which has been 

 grown in the open air in summer, and one which has been kept 

 in a hothouse ! The difference is, indeed, so great, that it is 

 hardly to be believed. The most effectual manner of cultivating 

 them, in winter, is to take great care not to keep them too warm, 

 and to see that their growth may not be accelerated, as a stag- 

 nation in vegetation should, if possible, be effected in the 

 plants. As soon as the weather is favourable in spring, and 

 strong frosts no longer dreaded, they should be set out in the 

 open air, in a warm protected situation, and treated in every 

 respect as much as possible like the genus Cereus. Bottom heat, 

 however, is not necessary for them in the open air, as they 

 thrive better without it ; the different species assuming a more 

 distinct character, and having a greater profusion of flowers. 



How very different, also, are the O. glomeratae, grown in the 

 open air in summer, and in the cold greenhouse in winter, to 

 those that have been continually in a hothouse, the temperature 

 of which is not natural to them. The same may be said of O. 

 cylindracea, and particularly O. tunica, excuviata, imbricata, 

 StapehV?, and decipiens. The first mentioned never has a stem 

 in its native country or in our cold greenhouses, but has, on the 

 contrary, a full branchless ccespes, in the form of a hedgehog. 

 This appearance is not uncommon, even on specimens from their 

 native country ; but their natural form and character are de- 

 stroyed by an injudicious mode of culture in our houses. 



Most of the species from North America, from Mexico, 

 Chili, and the South of Europe, may be kept through the winter 

 without fear of danger, by putting them in a temperate dry 

 greenhouse. If put in a hothouse for the winter, they will soon 

 become sickly, from attacks of the scale and other insects. 

 Dr. L. Pfeiffer's description and synonymes of the living Cacti 

 in the German gardens point out the native country of every 

 species of Cacti, and should, therefore, be used as a guide by 

 every cultivator. 



Art. X. On the Culture of the splendid Lake Rose, Nelumbium 

 specihsum Willd. By M. Lltbeck, Garden Director to Count 

 Harrach, at Bruck on the Leitha. 



(Translated from the Verhandlungen, Sfc, Berlin, vol, ii. p. 387.) 



This beautiful water-plant, so well known in the East and West 

 Indies, Persia, and in China, where it is the ornament of the 



L L 2 



