The Umbelliferae are proterandrous, and can hardly fail to be cross-fertilised by the many flies and small Hymenoptera which visit the flowers. (5/18. Hermann Muller ‘Befruchtung’ etc. page 96. According to M. Mustel as stated by Godron ‘De l’espèce’ tome 2 page 58 1859, varieties of the carrot growing near each other readily intercross.) A plant of the common parsley was covered by a net, and it apparently produced as many and as fine spontaneously self-fertilised fruits or seeds as the adjoining uncovered plants. The flowers on the latter were visited by so many insects that they must have received pollen from one another. Some of these two lots of seeds were left on sand, but nearly all the self-fertilised seeds germinated before the others, so that I was forced to throw all away. The remaining seeds were then sown on the opposite sides of four pots. At first the self-fertilised seedlings were a little taller in most of the pots than the naturally crossed seedlings, and this no doubt was due to the self-fertilised seeds having germinated first. But in the autumn all the plants were so equal that it did not seem worth while to measure them. In two of the pots they were absolutely equal; in a third, if there was any difference, it was in favour of the crossed plants, and in a somewhat plainer manner in the fourth pot. But neither side had any substantial advantage over the other; so that in height they may be said to be as 100 to 100.
19. DIPSACEAE.—Scabiosa atro-purpurea.
The flowers, which are proterandrous, were fertilised during the unfavourable season of 1867, so that I got few seeds, especially from the self-fertilised heads, which were extremely sterile. The crossed and self-fertilised plants raised from these seeds were measured before they were in full flower, as in Table 5/65.
TABLE 5/65. Scabiosa atro-purpurea.
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Crossed Plants.
Column 3: Self-fertilised Plants.
Pot 1 : 14 : 20.
Pot 2 : 15 : 14 4/8.