LECTURES, ae 
of some seems to indicate that they have gone through several periods 
of cross and self-fertilisation, according as the increase of vigour or 
the certainty of offspring was of greater importance. 
Another order that shews some of the primitive characteristics is 
that of Rosaca, but here we find a general advance in devices 
for disposal of seed (e.g. rose, strawberry, apple). It is remarkable in 
furnishing many examples of proterogyny (7.e., the stigma maturing 
first). otentil/a is the simplest genus : it contains ‘Tormentil, barren 
strawberry, and silverweed. ‘The flowers are generally yellow, and the 
stamens and pistils ripen together, but as the honey lies in a ring 
somewhat out beyond the stamens, cross-fertilisation is sometimes 
effected by an insect alighting on the petals and getting dusted with 
pollen, and then flying to the carpels of another flower. In wet weather 
the flowers scarcely open, and self-fertilisation must take place. The 
plants easily spread by means of runners. Avogaria vesca (the true 
strawberry) is white, and attracts many flies. It is considerably pro- 
terogynous. This makes cross-fertilisation more probable than in 
Potentil/a, and of course the succulent fruit is often devoured by birds, 
and so the plant is spread by their agency. Potentil/a comarum (marsh 
cinquefoil) is very remarkable. It grows on open bugs, and both petals 
and sepals contribute to its rich crimson colour. I have seen beds of 
it on the Yorkshire moors literally crowded with bees, and the honey 
is so plentiful that one can collect it on his fingers. My impression is 
that it is distinctly proterogynous, and so being would ensure cross- 
fertilisation, but 1 have been unable to find notice of it in any books. 
This development of a crimson colour in a simple genus in order to 
attract bees is curious. Perhaps flies are afraid of the water. 
We may notice an advance of colour among the Rosacee from yel- 
low to white and pink. Among the Audus genus the Raspberry has 
inconspicuous white flowers with the stamens crowded round the pistil 
in a narrow tube, and insects which seek the deeply-seated honey 
must generally effect self-fertilisation, but no doubt an occasional cross 
occurs. In the Blackberry, the outermost stamens and pistil, which 
are very far apart, mature first, so cross-fertilisation must often occur, 
asin Ranunculus. The crimson tips to the petals no doubt attract the 
great quantity of bees which visit it, in spite of the fact that there is 
no honey. ‘The Water Avens (Geum rzva/e) flowers early, and has a 
pink flush, with distinct honey guides, so it attracts many species of 
Bombus and Apis. It is proterogynous, and the stigmas project far 
beyond the still closed anthers, so at first cross-fertilisation is assured. 
Unfortunately, there is a slight gap between successive petals, and 
