122 THE FERTILISATION OF FLOWERS. [PART IIL. | 
open, but change gradually to blue, and in others the change to 
blue occurs immediately after opening, or even before. 
The most specialised form, V. calcarata, is almost always blue, 
but occasionally it reverts to the ancestral yellow colour (609). 
— ee 
Orv. POLYGALEZ. 
ae 
50. PotyGALaA comosa, Schk.—The structure of the flower 
of P. vulgaris, which agrees in all essential points with that of 
_ P. comosa, here figured, was first explained by Hildebrand (352). 
The two lateral sepals (alw), which are large and coloured, — 
render the flower conspicuous. The inferior petal (p’) is furnished 
weit) 
eet 
Fic. 37.—Polygala eomosa, Schk. 
1.—Flower in side view (the flower should naturally be horizontal). s, sepa!; p, petal; s’, one of — 
the two lateral sepals which play the part of a corolla; p’, anterior petal, provided with digitate — 
appendages, to which the insect clings. 
2.—Flower, from below. ; 
3.—Anterior petal, with the essential organs inclosed in it, from above. a, anthers; s, stigma, 
which applies sticky matter to the insect’s proboscis passing over it ; 1; spoon-shaped end of the — 
style, which receives the pollen issuing from the anthers. > 
4.—Pistil, from above. 
5.—Ditto, seen obliquely from above. 
6.—Ditto, in side view. 
7.— Anterior petal of a flower just about to expand, split to show the anther inclosed by it. 
8.—The united anthers. 
9.—An anther dehisced. po, pollen-grains. 
at its apex with finger-like processes, which support the bee when 
it alights. On the upper surface of this petal is a pouch with two — 
valves, inclosing the essential organs; in it lies the spoon-shaped 
style with its concavity upwards, and in this the anthers on both — 
sides lie and shed their pollen; close behind its hollow extremity 
the style bears a. viscid stigmatic lobe, bent sharply downwards, 
An insect which tries to reach the honey secreted in the base 
of the flower must, while clinging to the fimbriate processes — 
