C 90 ] 



One clafs containing all fuch plants as admit of a 

 promifcuous procreation, if the phrafe may be ad- 

 mitted, fo as thus to produce a mongrel breed, as is 

 particularly obvious in all the tribe of Braffica. 

 The other clafs, containing fuch plants as do not 

 admit of intermixture among the different varieties 

 by procreation, each of which continually retains its 

 diftinguifhing peculiarities, though reared in the 

 neighbourhood of other varieties of the fame clafs. 

 This is particularly the cafe with all the pea tribe, 

 and perhaps with all the papileonaceous clafs; 

 though I dare not venture to fay, that this rule 

 would prove general. As this diftinclion has not, 

 that I know of, hitherto been taken notice of, natu- 

 ralifts have not thought of affigning to each order 

 of plants the clafs they ought to be placed under in 

 that refpecl. Whether the Jolanum belongs to the 

 one or the other, I cannot tell, and therefore cannot 

 fay whether any new varieties of potatoes may be 

 expected from potatoes or not. 



Confidered in this point of view, there are pro- 

 bably other clalTes of plants that might -be efta- 

 blifhed, with regard to which profeffed florifts may 

 perhaps know fomething. As I have no preten- 

 fions to that name, I mention it here only to bring 

 jt under the view of thofe who have opportunities 



of 



