6 
of the New Zealand Flora,’”? so numerous 
are the intermediate forms between very 
distinct-looking species as to render the 
species excessively difficult of discrimina- 
tion, and to compel the adoption, for the 
purposes of an interim classification, of 
purely arbitrary characters founded on 
“prominent prevalent differences only.”’ Dr 
Hooker, in a communication addressed to 
myself, in reference to a large and varied 
collection of specimens which I forwarded 
to him in the early part of 1864, whilst he 
was engaged in compiling the Handbook, 
remarked on the possibility that the varia- 
tion referred to might be due to natural 
hybridisation, and asked me whether I 
thought this was the case. In reply I ex- 
pressed an opinion against the supposi- 
tion, 
_ Mr Travers then says that at the time 
he wrote to Dr Hooker he had, partly as 
the result of reading and partly from ob 
servation, arrived at certain opinions on the 
subject of plant variation, and he stated 
this in the following propositions :— 
lst. That certain classes of plants ex- 
hibit a greater tendency than others « 
acquire modifications as the result of 
changes in the conditions of life. 
2nd. That variation resulting from this 
cause may be sudden, or may _ result 
slowly from the operation of this cause 
acting continually and regularly upon the 
same species in the same locality. 
3rd. That the acquired modification will 
be transmitted to posterity, whether ac- 
quired suddenly or slowly. 
4th. That under domestication variation 
exhibits itself the more readily, because 
the plant is usually subjected to a more 
rapid succession of changes in the condi- 
tions of life, many of which are specially 
applied analogically, in order to produce 
some particularly desired result. 
Mr Travers explains at length the grounds 
on which he based his opinions, and 1a 
applying his views to the case of the New 
Zealand veronicas said he had taken into 
consideration the peculiar physical charac- 
ters of the country—the mountains of the 
Middle Island, its ocean surroundings, the 
