438 THE FERTILISATION OF FLOWERS. [PART III. 
brought in contact with the stigma, or some may even have fallen 
on the stigma previously. The flowers almost always bear seed, 
even in long-continued rainy weather, and therefore it is probable 
that self-fertilisation is effective; Hildebrand’s experiments are no 
evidence of the contrary, for he only showed that the stigma before 
opening is incapable of fertilisation (342). The large, widely-open 
flowers, naturally receive many unbidden and useless guests. If the 
plant is thus at a disadvantage in comparison with Antirrhinum, 
it has at least the advantage of letting its fertilising agents do their 
work more quickly, visiting more flowers in a given time. 
Visitors: A. Hymenoptera—Apide: (1) Bombus terrestris, L. 2; (2) 
B. hortorum, L. 9 ; (3) B. agrorum, F. 9, all three ab.,s. ; (4) Andrena coitana, 
K. 2 (Sld.), ab., c.p.; (5) Halictus cylindricus, F. 9, ab., ep. B. Coleoptera 
—(a) Nitidulide : (6) Meligethes, very ab. ; (6) Cryptophagide : (7) Anthero- 
phagus pallens, Ol., scarce; (c) Malacodermata: (8) Dasytes. The last five 
are quite useless visitors. 
Digitalis lutea, L., is fertilised by Bombus hortorum, L., which 
can only insert its head into the corolla (609). 
Digitalis ambigua, Murr. (D. grandiflora, Lam.), is fertilised by 
humble-bees, which creep bodily into the corolla. The flower is 
proterandrous, and bees begin at the base of the raceme and pro- 
ceed upwards (590, Ill.; 609). 
324, VERONICA CHAMaiDRYS, L.—Honey is secreted by a 
yellowish fleshy disk below the ovary, and lies in the base of the 
tube sheltered from rain by hairs on the corolla. The flowers are 
rendered conspicuous by their bright blue colour, and by associa- 
tion in racemes; dark blue radiating lines and a central white spot 
on the limb of the corolla guide insects towards the honey. The 
anthers and stigma ripen together; the style points obliquely 
downwards in front of the anterior (inferior) petal, the two stamens 
diverge on either side, and stand opposite to the lateral petals; 
fertilisation can therefore only be effected by the aid of insects. 
The anterior petal forms the most convenient landing-place, and 
the stigma is usually touched before the anthers by the ventral 
surface of the insect. The insect next tries to cling to the en- 
trance of the short tube with its forelegs, and in doing so it 
catches hold of the thin, flexible bases of the stamens: quite 
unintentionally it draws the stamens inwards beneath it, and dusts 
its ventral surface with pollen. The thinning of the style at its 
base is another adaptation towards this plan of cross-fertilisation, 
for it insures that the stigma shall be touched by the ventral 
