PART 11. ] THE MECHANISMS OF FLOWERS, 391 
_ The flowers of both species are adapted for insects in a simple - 
and effective way, so that cross-fertilisation in case of insect-visits 
and self-fertilisation in absence of insects are equally well insured. 
During the sunniest hours of the day, from about 9 A.m. to 3. P.M., 
_the petals (scarlet in A. arvensis, blue in A. cerulea), which cohere 
only by a ring at the base, spread out almost to a vertical plane, 
which has a diameter of 10 to 12 mm. in A. arvensis and rather 
less in A. cerulea ; the five stamens protrude from the centre of the 
flower, and the style projects between the stamens and curves 
downwards, so that an insect alighting on the lower part of the 
_ corolla and going towards the anthers comes first in contact with 
_ the stigma. Stigma and anthers ripen simultaneously; the pollen, 
Fia. 128. 
i, 2.—Anagallis arvensis, L, 
1.—Fully expanded, 
2.—Half closed. 
3, 4.—A. cerulea, Schreb.+ 
3.—Fully expanded. 
4—In section, (x 3}.) 
st, stigma. 
which coats the anthers all round, is all that the flowers offer to 
 insect-visitors, unless perhaps the delicate red, jointed, knobbed 
_ hairs which clothe the filaments are manipulated by flies with their 
- labellze, as I have observed in the case of the hairs upon the 
filaments of Verbascum.1 In either case it is to the stamens that 
_ insects come, and if they alight on the interior part of the flower as 
, _ the most convenient place for them, the downward curvature of the 
stigma suffices to insure cross-fertilisation. About 3 P.M. the 
_ sepals and petals begin to close up, so that the coloured surface 
_ formed by the corolla is reduced to less than a fourth of its former 
2 PES 
? According to: Delpino, . Anagallis.and also. Verbascwm-are adapted for pollen- 
| collecting ‘bees, “which oes to the staminal hairs; but as to Anagallis direct 
_ observation i is yet wanting (No. 178, 11. p. 290). 
reer e's 
