232 THE GREEN-HOUSE CATALOGUE. 



hence a general harmony and resemblance pervades 

 the whole order, and any person who knows or can 

 recollect the appearance of any one plant in that 

 order, will have a tolerably correct idea of the whole 

 group. The names -of these orders are generally 

 taken from some genus contained in it, which is 

 reckoned a prototype of the whole ; and thus to those 

 who recollect any species of that genus a very useful 

 practical idea of the order will be formed. Thus, 

 whoever knows any species of the genus My^rtus, 

 Myrtle, will be able to form a pretty good idea of the 

 order Myrteacece, and so on. This is our first reason 

 for arranging our catalogue according to the natural 

 method, rather than that of Linneeus^ or of any other 

 whatever. 



A second reason is, that plants of the same natural 

 order very often agree as to their modes of artificial 

 propagation and culture : many even agree in their 

 natural modes of propagation ; and with some orders, 

 as the AmaryllidecB, Rhodoracece, GeraniacecBi &c., 

 it is thought that mules may be formed between any 

 two species belonging to any one of these orders, 

 though of different genera. Hence, by treating of 

 the genera of these orders together, much repetition 

 is avoided, and the reader enabled to have a much 

 clearer idea of what he is reading, by always bearing 

 in mind the leading features of the plants of the order. 

 Thus, the order IridecB, which contains a consider- 

 able number of genera, almost all bulbs, growing in 

 the same soil, and propagated by offsets, if arranged 



