52 . MR. J. C. WILLIS ON THE 
angles (PI. ITI. fig. 1). The total width of the fully opened corolla 
is about 8mm. Itis white in C. alsinoides, pinkish in C. sibirica, 
with (in both) glossy yellow patches at the angle of limb and 
claw, upon the upper surface. These possibly serve as honey- 
guides; in some lights they themselves look rather like drops 
of honey upon the petals. In ©. sibirica a further honey- guide 
is formed by the veins of the petals, which are of a deeper red 
tinge than the tissue between. The stamens, five in number, 
are inserted upon the bases of the petals ; each bears a nectary 
on its base, on the inner side. The honey is thus exposed to 
short-tongued insects, as there are no special adaptations for its 
protection from them. The anthers are large and versatile, but 
hang down in such a way that the opening is extrorse. The ovary 
is small and bears a style, ending in a trifid stigma, whose stig- 
matic papille are on the inner (upper) surfaces only (figs. 1 
and 2). 
When the flower opens, the stamens stand up close round the 
style, bending outwards a little at their upper ends, with the 
anthers opening outwards. The style has its three stigmas 
closely folded in against one another (fig. 1). An insect alighting 
upon the corclla to obtain honey would, if large enough, be 
smeared with pollen upon its back. The stamens now begin to 
move slowly outwards and downwards, thus narrowing the space 
between them and the corolla, and rendering smaller insects 
liable to be smeared with pollen. At the same time the stigmas 
begin to separate and bend outwards. Finally the stamens lie 
completely prostrate upon the petals, and the stigmas are fully 
expanded and bent downwards, so as to be touched by the backs 
of insects visiting the flower (fig. 2). 
The flower, if visited by insects of moderate size alighting on 
the petals, will probably be cross-fertilized. Ifan insect alight 
in the middle of the flower, there is less likelihood of any fertili- 
zation occurring. Self-fertilization sometimes occurs in the later 
stages by the agency of the sleep-movements. The petals in 
closing lift the stamens up around the stigmas, and although it 
is the backs of the anthers that are uppermost, and they are 
often empty at this stage, some pollen may often get upon the 
stigmas. That this method does not always work is seen from 
the fact that a large number of the flowers upon the plants ex- 
amined set no seed. The only insect that was observed visiting 
the flower was a Meligethes Sp, 
