. Un manuel de botanique pour les collèges et universités ... La botanique. REPRODUCTION ET DISPERSION DES ANNÉES 90, grâce à l'élargissement de l'ovaire avec ou sans la modification d'autres organes, est appelé le fruit, et il est évident que son rôle principal est la protection de l'élaboration de semences. La plupart des jeunes fruits contiennent suffisamment de la chlorophylle pour les rendre manifestement vert, et ils ont sans doute elle la plupart des aliments utilisés dans leur développement. Parfois, comme dans l'orme, les fruits verts sont importants avant l'apparition des feuilles, ou, comme dans le Cakile, après les feuilles ont disparu ; dans ce cas, le rôle de l'alimentation

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. A textbook of botany for colleges and universities ... Botany. REPRODUCTION AND DISPERSAL 90s through the enlargement of the ovary with or without the modification of other organs, is called the fruit, and obviously its chief role is the protection of the developing seeds. Most young fruits contain sufficient chlorophyll to make them conspicuously green, and they doubtless manu- facture much of the food utilized in their development. Sometimes, as in the elm, green fruits are prominent before the leaves appear, or, as in Cakile, after the leaves have gone; in such cases the food-making role would seem particularly significant. At maturation the fruit by reason of its edibility and showiness often is a means of attracting seed- dispersing animals, and in other ways it is connected with the process of dissemination. General characteristics of seeds. — Morphology. — The seed, which is an enlarged and matured ovule, is one of the most complex organs found in plants. The ovule, which is a sporophytic organ, serves as a domi- cile for the female gametophyte, and afterwards for the new sporophyte that develops from the fusion of the sperm and the egg. This structure, which thus is made up of elements from three generations, grows to a certain size, varying with the species, whereupon the integument de- velops into the seed coat or testa, and the growth of the sporophyte within is checked. Henceforth the structure may be called a seed rather than an ovule, so that a seed may be defined as a young sporophyte in a state of arrested development, enclosed within a modified ovule integument, the testa; in addition, the gametophytic generation may or may not be represented by the endosperin (but see p. 270). Developmental features. — The ovules commonly arise on the margins of the carpels, to which they are attached by a stalk, ihe funiculus. The central mass of tissue, the nucellus, usually is y'f'^ ^ z^'T"^ //1 '205 enclosed by one or two integuments arising from

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