HYBRID INTERMIXTURES. 
379 
closer affinity than the others, and their distinction is more 
questionable. I am, however, by no means satisfied that, if 
they are distinct, Petunia linearis (Salpiglossis integrifolia, 
Bot. Mag. Nierenbergia, Sweet's B. f. g.) may not belong 
to a fifth genus. It is certainly neither a Salpiglossis nor a 
Nierenbergia, and its seeds conform with Petunia, but it has 
a different aspect, and I cannot cross it with the other sorts 
of Petunia. It will belong at least to a separate section of 
Petunia with linear leaves. It is very remarkable that, 
although there is a great difference in the form of the flower, 
especially of the tube, of P. nyctanigenseflora and phoenicea, 
the mules between them are not only fertile, but I have found 
them seed much more freely with me than either parent. 
The mules I had raised from the former by the latter, having 
been forced early in the spring of 1835, set their seed before 
any other Petunia was in flower on the premises, and must 
therefore have been fructified by its own pollen. The white 
impregnated by the dust of the mule, and the mule by it, 
produce a great deal of sporting, but from a pod of the above- 
mentioned mule to which no pollen but its own had access, 
I had a large batch of seedlings in which there was no varia- 
bility or difference from itself ; and it is evident that the 
mule planted by itself, in a congenial climate, would repro- 
duce itself as a species ; at least as much deserving to be so 
considered, as the various Calceolarias of different districts 
in South America. 
I have little to add to this treatise, but my regret that it is 
necessarily so imperfect ; and, from the nature of the subject 
and the additions made to it since it was first written, of 
somewhat too desultory a character. I hope, however, that 
it may have the effect of removing some erroneous impres- 
sions, and contribute its humble mite towards the elucidation 
of truth ; and that, by giving the public a clearer view of 
what has been effected, it may enable those, who are dis- 
posed to pursue experiments on this subject, to conduct them 
with greater advantage. I have by no means enumerated 
all the genera in which crosses have been lately introduced, 
as for instance, Potentilla and Anagallis, in the last of which 
I have seen a remarkable result in the production of a red- 
dish purple flower, by the union of the orange with the 
bright blue. I have an hybrid from the little Hibiscus 
ficulrieus by manihot, which, with leaves that preserve the 
form of those of ficulneus, has the vigour and stature of ma- 
