. Botany all the year round; a practical text-book for schools. Botany. 200 THE FLOWER the inner or ventral sutures, so that there are only three true carpels. Select a flower that has begun to wither, so that the ovary is well developed, cut a cross section near the middle and try to make out the number of cells, or internal divisions. Make an enlarged sketch of the sec- tion as it appears under the lens (see Fig. 383), showing the arrangement of the parts, also a longitudinal section (Fig. 382) showing their relative vertical position. Label the little round bodies that represent the undevel
. Botany all the year round; a practical text-book for schools. Botany. 200 THE FLOWER the inner or ventral sutures, so that there are only three true carpels. Select a flower that has begun to wither, so that the ovary is well developed, cut a cross section near the middle and try to make out the number of cells, or internal divisions. Make an enlarged sketch of the sec- tion as it appears under the lens (see Fig. 383), showing the arrangement of the parts, also a longitudinal section (Fig. 382) showing their relative vertical position. Label the little round bodies that represent the undeveloped seeds ovules, the surface to which they are attached, placenta, and the cavities, or divisions containing them, cells, or loculi (singular, loculiis\ How many of these are there ? Compare these sketches of the ovary with your drawings of dehiscent fruits in Sections 93-109. What correspond- ences do you notice between them 1 As the ovary is merely an undeveloped fruit, and the ovules immature seeds, their structure is the same as that of these parts, and the same terms are used in describing them (Sees. 73-79, and 93-109). 288. Numerical Plan.—Now make a horizontal diagram, after the model given in Figure 384, showing the manner of attachment of the different cycles — sepals, petals, stamens, and pistils, the number of organs in each set, and their mode of alternation with the organs of the other cycles. Notice that in the star-of-Bethle- 384 — pTorizontAi ^^"^ ^^^ similar flowers, the parts of each diagram of a flower set are in threes, or multiples of three. The*dot re'presl^riJs This is Called the numerical plan of the the growing axis flower, and is the prevailing number among e p an. monocotylcdons. It is expressed in botani- cal language by saying that the flower is trimerous, a word meaning measured, or divided off into parts of three. 289. Vertical Order. — Next make a vertical diagram of your specimen after the manner shown in Figure 372, and note car
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