410 
probably entail a discussion of the several types of floral 
structure found in the genus Salvia? We also look for a 
discussion of the question whether or no the fact that 
the flowers were pressed against the netting could so far 
disturb the mutual relations of the parts as to bring about 
self-fertilisation. 
The same want of full discussion is felt in his critique 
on Darwin’s observation on the broom (Sarothamnus 
scoparius). Darwin says the flowers were 
“extremely sterile when the flowers are neither visited by 
bees, nor disturbed by being beaten by the wind against 
the surrounding net.” 
The Field Naturalist quotes this passage incorrectly, 
omitting “ when the flowers are neither visited by bees ”— 
and these words are of some importance, for they show 
that the disturbance by the wind was believed to have 
an effect analogous to that produced by insects. In 
another passage (“ Cross and Self-Fertilisation,” edit. ii. 
p- 164) Darwin states that “if the flowers are not dashed 
by the wind against any object, the keel never opens.” 
If the flower is not opened the style remains in the keel 
surrounded, but either not fertilised or imperfectly 
fertilised by its own pollen. But if the style and 
stamens are freely exposed, as would be the case in the 
flowers opened by the wind’s action, the flowers may 
conceivably be “dashed against” each other and fer- 
tilised, even if they cannot be visited by insects. The 
whole economy of the broom flower should be thoroughly 
known, and, indeed, fresh observations should be made, 
before it is possible to draw the conclusion of the Field 
Naturalist, that the sterilising action of the net accounts 
for the results. 
The same sort of thing is put forward in the case of 
Reseda lutea, Here Darwin says, 
“The bees were able to suck the flowers through the 
meshes, and brought pollen to them from the neighbour- 
ing plants.” 
The Field Naturalist says (p. 13), 
“The bees could not possibly reach with their proboscis 
the side or inside flowers, yet ‘the branches were loaded 
with capsules.’ ” 
As the Field Naturalist was not present when the bees 
brought pollen to the mignonettes, and as one of the best 
observers in the world was present, we need not waste 
more time over this case. 
In “Cross and. Self-Fertilisation,” from which the 
Field Naturalist takes his cases, he might have found, if 
he had looked for them, facts which he will find difficult 
to fit to his theory of the “denaturalising” effect of the 
net. Darwin gives (“Cross and Self-Fertilisation,” 
edit. ii. p. 357-369) two lists :—(1) Containing plants 
which, when insects are excluded, are quite sterile, or 
produce, as far as he could judge, less than half the 
normal number of seeds. (2) Containing those which, 
when protected from insects, are either quite fertile or 
yield more than half the normal number of seeds. The 
Field Naturalist is bound to account for the fact that 
many plants are extremely fertile under the net, and he 
must account, too, for the fact that, broadly speaking, 
there is a difference between the type of flower found in 
the two classes. Or, to put it more accurately, in the 
first or sterile lot 65 per cent. of the genera have asym- 
NO. 1713, VOL. 66] 
NATURE 
{[Aucust 28, 1902 
metrical or otherwise specialised flowers, while in the 
fertile lot the specialised genera are 43 per cent. 
Why, according to the Field Naturalist’s view, should 
the net be less hurtful to the simple unspecialised 
flowers? According to the rational view of the matter 
taken by most botanists, it was to be expected that 
specialised flowers would be more highly sterile, when 
insects are excluded, than simple  unspecialised 
flowers. But it is useless to argue thus, for if a female 
dicecious plant were placed under a net, and were found 
to be sterile, the Field Naturalist would doubtless ac- 
count for its sterility by the denaturalising influence of 
the net, not by the fact that pollen could not reach its 
stigmas. 
Chapter xiii., on “ The So-called Dichogamous Plants,” 
may be taken as another instance of the Field Naturalist’s 
method of treating a scientific problem. His notions on 
this subject seem to be taken from Lord Avebury and 
Dr. Wallace, neither of whom can rank as original 
authorities on the question, while we look in vain for 
references to Sprengel, Delpino and Hildebrand. This 
is only one instance of the author’s ignorance of the 
literature of his subject. It is probably in consequence 
of want of knowledge that he sets up an incorrect defini- 
tion of dichogamy against which to direct his arguments. 
He ought to be aware that dichogamy does not neces- 
sarily mean a complete separation in time of the staminal 
and stigmatic functions. However, allowing this serious 
flaw in his point of view to pass, let us see how he deals 
with a strongly dichogamous species, 47 maculatum. 
He tells us that no flower gives clearer evidence of its own 
self-fertilisation than the Arum. Yet hequotes an ob- 
servation of Darwin, who saw minute flies emerge from 
an Arum, dusted with pollen, and subsequently visit a 
neighbouring plant. Here Darwin found pollen within the 
spathe, though the stamens had not burst. No one will 
pretend that this one observation is conclusive, but it 
points clearly to the view accepted by botanists ‘that flies 
carry pollen from the older to the younger spathes, thus 
fertilising the female flowers! before the pollen in the 
spathe is ripe. 
The Field Naturalist principally devotes himself to 
trying to prove that the Arum does not imprison flies with 
sufficient regularity and in sufficient numbers to be of 
any use. He writes (p. 80) :— 
“About the forced imprisonment of small flies, Darwin 
says, ‘this statement has [now] been shown by Hilde- 
brand to be erroneous,’ and Darwin proves that it is 
incorrect, and that the small flies can escape before the 
hairs above wither, by his own experiment” (“Cross and 
Self-Fertilisation,” edit. ii. p. 420). 
It so happens that Hildebrand’s statement (according 
to Darwin) refers to Aristolochia, not to Arum. But 
even if it had referred to Arum it would only have illus- 
trated another piece of inaccuracy of the Field Natural- 
ist. What was shown by Hildebrand (as quoted by 
Darwin) to be incorrect was the old statement that 
flies which enter the flowers never escape, whereas the 
Field Naturalist seems to consider it an argument against 
imprisonment occurring at all. His own observations 
are on a level with this loose treatment of the problem, 
for he does not say in which of Delpino’s stages were the 
J 1 Often described as ovaries. 
