Cultivatio7i of the Cacti. 511 



of soil, or by putting the plants in a hotbed full of vapour, he 

 will not succeed ; and unfortunately too many gardeners fall 

 into this error, and by this means the best and rarest plants, 

 which have been preserved during a long voyage, have been 

 totally lost by a wrong mode of culture. 



Where Nature cannot be imitated exactly, the most earnest 

 wish of the gardener should be to approach her as near as pos- 

 sible, and in this consists the great art of the cultivator. 



The different kinds of soils are not alone necessary for the 

 growth of the plants : situation and temperature must also be 

 taken into consideration. For some years back collections of 

 mammillarias, from whatever parts of the world they came, 

 were grown in our hothouses, and many of them are still kept 

 there. The West Indian species, such as M. simplex, prolifera, 

 and straminea, 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 con- 

 sideration, that almost all the species brought to us in modern 

 times from Mexico belong to our tepidaria, and therefore 

 require a temperature of from 6° to 8° of Reaumur (45*5° to 50° 

 Fahr.), so as to produce a healthy and vigorous state of vege- 

 tation, 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 mam- 

 millarias from Mexico, by their being placed in hothouses ; and 

 it is from this circumstance, that those plants that have been 

 I'aised from seed, or by other means, in Europe, have not the 

 least resemblance to the 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 re- 

 ceive in great numbers from their native country : other plants, 

 again, of the same family, which have been kept in an over- 

 heated temperature, are hardly to be recognised, 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 Conothelse, 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 a few exceptions, should be grown in a much lower tempe- 

 rature than has hitherto been done. 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 character of the 

 plant can be obtained. When treated in this manner, they 

 1841. — X. 3d Ser. L l 



