The Development of the Flowers from the Curd of Broccoli (Brassica oleracea botrytis)

Abstract

THE oleracea structure botrytis) of the appears head or in curd the literature of the broccoli to have and been cauliflower misunderstood. {Brassica oleracea botrytis) appears in th literature have been misu derstood. Masters (1849) says: 'The cauliflower and broccoli afford familiar illustrations of the hypertrophy of the flower stalk accompanied by a corresponding defective development of the flowers' (p. 421). According to Worsdell (1915), ' . . the whole inflorescence becomes greatly hypertrophied, involving very copious branching of the pedicellar system, and in which the flowers are completely suppressed, has given rise to the variety of the cabbage known as the cauliflower . . .' (vol. ii, p. 40), and 'Examples are afforded by the cauliflower and broccoli, in which, owing to excessive hypertrophy of the pedicels, the flowers are not developed, or only a vestigial calyx' (p. 248). From this it would appear that the curd has developed into a purely vegetative organ. Actually the whole inflorescence is hypertrophied, but the flowers are not defective, the curd being merely an intermediate stage in the development of the flowers and seed. After the curd has developed it is rapidly disrupted by the elongation of the main stalks to varying degrees. Plate XXIX, Figs 1-6, show successive stages in the further development of one of these pieces of the disrupted curd. Fig. i. ist day, the masses of white hypertrophied flowers are separating by the elongation of the secondary stalks. Fig. 2. 3rd day, the stalks are elongating further and losing their fleshy character. The white curd is developing pigment (in the centre at 2 o'clock), while (at 10 o'clock) pigment has been developed and the hypertrophied bud tissue has begun growing out into buds. Fig. 3. 6th day, the same processes are continuing and the buds in the centre mass have now differentiated their sepals. Fig. 4. 8th day, the minor branches are continuing to elongate and the pedicels of the buds are lengthening. At the right-hand side is a partially differentiated mass of buds that is beginning to abort; probably due to starvation, as it did not appear to have suffered any injury. Fig. 5. 17th day, here the buds are nearly ready to burst-. The aborted [Annals of Botany, N.S. Vol. II, No. 7, July 1938.]