330 
DARWINISM 
CHAP. 
tubular flowers increasing in length and irregularity, till in 
some, like our common honeysuckle, they are adapted for 
fertilisation by moths only, with abundant honey and 
delicious perfume to attract them. In the Scrophulariaceae 
we find open, almost regular flowers, as Veronica and 
Verbascum, fertilised by flies and bees, but also self-fertilised ; 
Scrophularia adapted in form and colour to be fertilised by 
wasps; and the more complex and irregular flowers of 
Linaria, Rhinanthus, Melampyrum, Pedicularis, etc., mostly 
adapted to be fertilised by bees. 
In the genera Geranium, Polygonum, Veronica, and several 
others there is a gradation of forms from large and bright 
to small and obscure coloured flowers, and in every case the 
former are adapted for insect fertilisation, often exclusively, 
while in the latter self-fertilisation constantly occurs. In the 
yellow rattle (Rhinanthus Crista-galli) there are two forms 
(which have been named major and minor), the larger and 
more conspicuous adapted to insect fertilisation only, the 
smaller capable of self-fertilisation ; and two similar forms exist 
in the eyebright (Euphrasia officinalis). In both these cases 
there are special modifications in the length and curvature 
of the style as well as in the size and shape of the corolla; 
and the two forms are evidently becoming each adapted to 
special conditions, since in some districts the one, in other 
districts the other is most abundant. 1 
These examples show us that the kind of change suggested 
above is actually going on, and has presumably always been 
going on in nature throughout the long geological epochs 
during which the development of flowers has been progressing. 
The two great modes of gaining increased vigour and fertility 
—intercrossing and dispersal over wider areas—have been 
resorted to again and again, under the pressure of a constant 
struggle for existence and the need for adaptation to ever- 
changing conditions. During all the modifications that ensued, 
useless parts were reduced or suppressed, owing to the absence 
of selection and the principle of economy of growth ; and thus 
at each fresh adaptation some rudiments of old structures were 
1 Muller’s Fertilisation of Flowers, pp. 448, 455. Other cases of recent 
degradation and readaptation to insect - fertilisation are given by Professor 
Henslow (see footnote, p. 324). 
