DESTEUCTIVE AND CONSTEUCTIVE TENDENCIES 469 
I showed him the Berberis which confounded him ; his 
only objection (or crotchet) was the simple racemed form 
of aristata, as different from the panicled form of the same 
plant. These two he had studied living and found them 
always distinct though growing side by side ; I showed him 
loads of specimens he could not decide between ! but the 
fact of his having found them distinct side by side outweighed 
all others. Now what are we to give for such facts ? They 
are most important, but are we to admit every collector's 
(however good a botanist) testimony on such a point, as 
of specific importance ? Thomson thinks lyciimi the only 
good one on the same grounds, whereas Madden vows he 
found these passing into one another every way. I took 
asiatica for the best marked of them all, and that again 
Madden denies m toto. I wish you would kindly tell me 
what your own ' particular variety ' was amongst them. 
In September 1853 he tells Munro : 
I am travailing through an Essay on ' Species, their 
distribution and variation,' for the New Zealand Flora 
Introduction [' which I hope;' he afterwards tells Bentham, 
' will be read, though I cannot flatter myself it will be of 
any great use '], chiefly intended to open students' eyes to 
the great leading facts of the case and to inculcate caution, 
or they will have their Flora in a pretty mess, for it is a 
frightfully variable one. 
But his apparently destructive tendencies were really con- 
structive. He tells Harvey (January 1852) : 
I am combining very many species with Tasmanian and 
South American plants — many are identical without trace 
of change, which led me to claim some variation for others 
• which belong to very widely different genera. . . . The up- 
shot will be the total bouleversement of our previous ideas of 
; the extent &c. of the Flora and a very close alliance indeed 
\ with Austraha. I am really extremely anxious to get the 
[ thing well done, but greatly doubt people's being satisfied 
' with my destructive propensities, which however are far 
more really constructive than those who have few materials to 
work from and judge by can form any idea of. 
