312 DR. J. D. HOOKER'S PRESIDENTIAL ADDRESS 
- that my botanical Scit of these homely plants had been but little deeper 
than Peter Bell’s, to w 
E - rain by the river's brim 
llow Primrose was to him, 
p it was nothing more.’ 
“ Analogous observations on the dimorphism of Flax-flowers and their allies 
stigma, but invariably potent when applied to the stigma of the other form 
flower ; and yet pollens and dp of the two kinds are utterly undistinguish- 
able under the highest powers of the microscope. 
* His third iste is a very long and laborious one on the common 
Loosestrife, Lythrum Salicaria (‘Journal of the Linnean Society, vol. vill. 
p. 169), which he showed to be trimorphic ; this one species having three kinds 
of flowers, all annually abundantly a and as different as if they be- 
ow 
differing in form and function. We have in this plant then, six kinds of pol- 
len, of which five at least are essential to complete freu and three distinct 
forms of style. To prove these various differences, and that the coadaptation 
of all these stamens and pistils was essential to complete fertility, Mr. Darwin 
had to institute eighteen sets of observations, each consisting of twelve experi- 
ments—216 in all. Of the labour, care, and peeeney requises to guard such 
experiments against the pe of error, those alone can tell who kuow ex- 
perimentally how difficult it is to hybridize a large-flowered gs of simple 
form and structure. mt results in this case and in those of a number of allied 
plants experimented on at the same time, is what the author’s sagacity pre- 
dicted ; the rationale F^ Ta whole was demonstrated, and he finally showed 
not only how nature might operate in bringing these complicated modifica- 
tions into harmonious operation, but how, through insect agency, she does 
E. and why she does it too. 
“ Tt is impossible even to enumerate here the p important generalizations 
that have followod feom. those and pther papers of Mr.  Berein e; 3 on the fertili- 
zation of plants ; ally the 
most subtle, S like masy other apparent commonplaces, are  whak aan 
never occur to c minds ; as, for instance, that all plants with con- 
spicuously-coloured "lawem. or powerful odours, or honeyed. secretions, are fer- 
tilized by insects; all with inconspicuous flowers, and especially such as have 
our globe could not have been ornamented wi b ale flowers, but 
consisted of such plants as Pines, Oaks, abet Nettles, e 
“The only other botanical paper of Mr. Darwin’s to eh I can especially 
allude is that ‘On the Habits and Movements of Climbing Plants’ (‘ Journal 
of the Linnean Society,’ vol. ix. p. 1), which is a most elaborate investigation 
