. A Manual of botany : being an introduction to the study of the structure, physiology, and classification of plants . Botany. 332 PEEISPEEM OE ALBUMEN OF THE SEED. integuments and embryo alone. In Santalum, Osyris, and Loranthus, Griffith says the ovule is sometimes reduced entirely to a sort of embryonary sac. In Avicennia the embryo, at its maturity, is on the outside of the nucleus and body of the ovule. In other cases it enlarges to a certain extent, filling the embryo-sac completely or partially, and ⢠only encroaching slightly on the cells of the nucleus. The cells sur- rounding the em
. A Manual of botany : being an introduction to the study of the structure, physiology, and classification of plants . Botany. 332 PEEISPEEM OE ALBUMEN OF THE SEED. integuments and embryo alone. In Santalum, Osyris, and Loranthus, Griffith says the ovule is sometimes reduced entirely to a sort of embryonary sac. In Avicennia the embryo, at its maturity, is on the outside of the nucleus and body of the ovule. In other cases it enlarges to a certain extent, filling the embryo-sac completely or partially, and ⢠only encroaching slightly on the cells of the nucleus. The cells sur- rounding the embryo then become filled with a solid deposit called albumen, consisting of starchy, oily matter, and nitrogenous compounds. To this some have applied the term perisperm (tiiI, around, and eiri^f/.a, seed); others, that of endosperm {tvbov, within). The name, perispermic â albumen, or perisperm, is often restricted to that found in the cells of the nucleus alone, outside the embryo-sac (fig. 576 n); endospermic albumen, or endosperm, to that found within the embryo-sac alone (fig. 576 se), as in Chelidonium majus, Eanunculacese, Umbelliferse, and in many Endogens, etc. Sometimes both kinds of albumen occur. Fig. 689. Fig. 590. in the same seed, as in Nympheeaceae and Piperacese. In some instances the albumen is produced in the region of the chalaza. In some Scrophu- larias the embryo-sac forms little cavities or bags, which in the ripe seed remain as appendages to the albumen. Seeds in which the â¢embryo occupies the entire seed, are called exaUmminous (ex, without), as Oompositse, Cruciferse, and most Leguminosae, while others having separate albumen are albuminous. The larger the quantity of albumen in a seed the smaller the embryo. In figs. 588 to 590 the relative proportion which the embryo bears to the albumen or perisperm in different seeds is shown; e being the embryo with its cotyledons and young root, p the perisperm, t the coverings of the seed, / the funiculus or
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