. Botany of the living plant. Botany. THE CARPEL AND OVULE 259 the body of the ovule is straight, but it is inverted or anatropous, so that the micropyle hes close to the attachment of the funiculus on tlie carpel. This is seen in Fig. 206, which shows an ovule of Caltha cut in median section, at the time when it is ready for fertilisation. The nucellus is the essential part of. the ovule, the integuments and the funiculus being accessory. They provide respectively for external protection, and attachment with conduction of supplies. Moreover, the nucellus is the part first formed. In a young s
. Botany of the living plant. Botany. THE CARPEL AND OVULE 259 the body of the ovule is straight, but it is inverted or anatropous, so that the micropyle hes close to the attachment of the funiculus on tlie carpel. This is seen in Fig. 206, which shows an ovule of Caltha cut in median section, at the time when it is ready for fertilisation. The nucellus is the essential part of. the ovule, the integuments and the funiculus being accessory. They provide respectively for external protection, and attachment with conduction of supplies. Moreover, the nucellus is the part first formed. In a young state it may be. Fig. 207. Median section of a young ovule of Caltha, anatropous curvature still incomplete, and the nucellus only partially covered by the integuments. The spore-mother-ccll has divided once, and the second division to form the tetrad is already indicated. ( X 200.) F. O. B. found already well advanced, though the integuments are incomplete, and the funiculus is only beginning to assume that curvature whicii results in the inversion of the mature ovule (Fig. 207). At the period of blooming the nucellus consists of a peripheral covering of thin-walled cells, of varying thickness in different groups , of plants, enclosing one large cavity, which, though its contents arc I complex, is developed from a single cell. This is the Embryo-Sac, or Megaspore. It attains its large size by encroaching on the adjoining cells as it develops, by a process of digestion ; this leads to their collapse, and the final absorption of their substance. The sac is limited. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bower, F. O. (Frederick Orpen), 1855-1948. London, Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1919
