. A text-book of botany for secondary schools. Botany. ANGIOSPERMS 229 (§ 123). On the outside of this ovule-one or two special coverings are developed, called integuments. These integu- ments grow up about the ovule, but do not completely cover it at the top, leaving a little opening called the micropyle (little gate). This micropyle is a very important. Fig. 217.—Diagrammatic longitudinal sections of ovules, showing outer (oi) and inner (ii) integuments, micropyle (m), nucellus (n), and megaspore (eTn), the last often called embryo sac: A, erect ovule; B, curved ovule; C, inverted ovule. fea
. A text-book of botany for secondary schools. Botany. ANGIOSPERMS 229 (§ 123). On the outside of this ovule-one or two special coverings are developed, called integuments. These integu- ments grow up about the ovule, but do not completely cover it at the top, leaving a little opening called the micropyle (little gate). This micropyle is a very important. Fig. 217.—Diagrammatic longitudinal sections of ovules, showing outer (oi) and inner (ii) integuments, micropyle (m), nucellus (n), and megaspore (eTn), the last often called embryo sac: A, erect ovule; B, curved ovule; C, inverted ovule. feature in the ovule and also later in the seed. The body of the ovule within the integuments is called the nucellus, and within the nucellus the large spore (megaspore) lies embedded (Fig. 217). The three types of ovule are shown in Fig. 217: the erect ovule (A), the curved ovule (B), and the inverted ovule (C), the last being the most common. 136. Floral numbers.—In many flowers there is no regularitj^ in the number of members in each set. For example, in the water-lily petals and stamens occur in indefinite numbers; and in the buttercup the same is true of stamens and carpels. In most flowers, however, definite numbers appear either in some of the sets or in all of them. When these definite numbers are present, they are prevail- ingly either three or five; that is, there are either three or five sepals, petals, stamens, and carpels; although it is very common to have two sets of stamens, in which case they number six or ten. These numbers appear so constantly in great groups that the two grand divisions of Angio-. 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 Coulter, John Merle, 1851-1928. New York, D. Appleton
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