THE FLORAL WORLD AND GARDEN GUIDE. 367 



prvlifera, and strcwiinea, which have been long in our possession, and 

 which really require a greater degree of heat than those from Mexico, 

 probably gave us the idea. We do not take into consideration that 

 almost all the species brought to us from Mexico belong to our 

 tepidaria, and therefore require a temperature of from 45 deg. to 50 

 dog. Fahr., so as to produce a healthy and vigorous state of vegeta- 

 tion, and some of the species even do better with a less degree of 

 heat. A great many examples might here be given of the alterations 

 that are produced in the form and habit of the Mammillarias from 

 Mexico, by their being placed in stoves ; and it is from this circum- 

 stance that those plants that have been raised from seed, or by other 

 means, in Europe, have not the least resemblance to tlie parent 

 plant, and are therefore received in the trade as new species — indeed, 

 in some instances, the most skilful connoisseurs and the best 

 botanists have been often deceived with these plants. As is the 

 case with most other plants, this family is subject to sport, and 

 these sports we receive in great numbers from their native country ; 

 other plants, agaiu, of the same family, which have been kept in an 

 over-heated temperature, are hardly to be recognized, and thus 

 errors are propagated, arising from an impossibility of distinguishing 

 the species or variety. If we contemplate the host of varieties of the 

 division Conothelce, which we have partly from their native country 

 and partly from plants raised in Europe, it will confirm this statement. 



It may be seen from this that the Mexican Mammillarias, with 

 few exceptions, should be grown in a much lower temperature than 

 is frequently the case. To prepare them for it, they should be 

 planted in beds in the open air, so that they may become strong, 

 and remain there till late in the autumn ; and it is only thus that 

 the natural habit and peculiar cliaracter of the plant can be 

 obtained. When treated in this manner they flower plentifully, 

 and produce an abundance of fruit, and are not infested by insects, 

 which is unavoidably the case in hot-houses. 



These are the advantages which are obtained from a successful 

 treatment of this favourite genus of plants. Many gardens now 

 possess very good collectious by following this plan. 



The Melocacti, on the contrary, require a higher degree of tempe- 

 rature, and therefore ought to be in the stove. Most of them come 

 from the West Indies, Curacoa, St. Thomas's, etc. There are several 

 varieties in this group, which approach more or less to the Meloc'actus 

 communis. Whetlier they are all to be considered as varieties must 

 be, from careful consideration, afterwards determiued. Most of the 

 original plants evince by their roots that they grow in a red loamy 

 and stony soil ; and these, in my opinion, should also be cultivated 

 as I liave mentioned. 



The Echinocacti require somewhat more heat than the Mammil- 

 larias, yet they may be cultivated in beds in the open air in summer. 

 In winter they should be kept in a temperature of 50 deg. to 55 deg. 

 Fahr., and ought to have but very little water; and if thev have 

 taken firm root in summer they may be kept quite dry, and will not 

 be in any danger. Erom this necessary state of rest, a profusion of 

 flowers will be produced on the plants. 



