From such cases as these
we may pass on to certain Labiatae, for instance, Salvia Horminum in which (as I
hear from Mr. Thiselton Dyer) the upper bracts are enlarged and brightly
coloured, no doubt for the same purpose as before, with the flowers suppressed.
In the Carrot and some allied Umbelliferae, the central flower has its petals
somewhat enlarged, and these are of a dark purplish-red tint; but it cannot be
supposed that this one small flower makes the large white umbel at all more
conspicuous to insects. The central flowers are said to be neuter or sterile,
but I obtained by artificial fertilisation a seed (fruit) apparently perfect
from one such flower. (Introduction/12. 'The English Flora' by Sir J.E. Smith
1824 volume 2 page 39.) Occasionally two or three of the flowers next to the
central one are similarly characterised; and according to Vaucher "cette
singuliere degeneration s'etend quelquefois a l'ombelle entiere."
(Introduction/13. 'Hist. Phys. des Plantes d'Europe' 1841 tome 2 page 614. On
the Echinophora page 627.) That the modified central flower is of no functional
importance to the plant is almost certain. It may perhaps be a remnant of a
former and ancient condition of the species, when one flower alone, the central
one, was female and yielded seeds, as in the Umbelliferous genus Echinophora.
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