. Practical botany, structural and systematic, the latter portion being an analytical key to the wild flowering plants, trees, shrubs, ordinary herbs, sedges and grasses of the northern and middle United States east of the Mississippi. Botany. 63 PRACTICAL BOTANY. trorse (turned inward), when it faces the pistils, as in Magnolia (Fig. d). The VEESATILE ANTHEE is usuallj introTse (turned to- • ward the axis of the flower)—rarely extrorse. The CONNECTIVE is often inconspicuous, or even want- ing, so that the anther-lohes are "in close contact. Some- times it outruns the anther and tips it w
. Practical botany, structural and systematic, the latter portion being an analytical key to the wild flowering plants, trees, shrubs, ordinary herbs, sedges and grasses of the northern and middle United States east of the Mississippi. Botany. 63 PRACTICAL BOTANY. trorse (turned inward), when it faces the pistils, as in Magnolia (Fig. d). The VEESATILE ANTHEE is usuallj introTse (turned to- • ward the axis of the flower)—rarely extrorse. The CONNECTIVE is often inconspicuous, or even want- ing, so that the anther-lohes are "in close contact. Some- times it outruns the anther and tips it with an appendage, as in Magnolia, Ziriodendron, Violet, Asaricm, etc. 113. At maturity, the anther-cells open, or become dehiscent, to discharge the pollen. There are three modes of dehiscence—namely, a, the valvular—that is, the split- ting open by two lateral, longitudinal lines, one on each lobe of the anther (Figs, y, g); h, the porous, in which the cells open by a pore or chink at the apex of the lobe (as in Pyrola, Fig. K), and each lobe ia sometimes prolonged into a tube, as in Yaccinium,' c, the opercular, in which each cell opens by a lid, which, as though attached to the apex by a hinge, turns upward like a trap-door, fis in JBerieris (Fig. i). The commonest mode of dehiscence is the Cut XI. 114. The POLLEN, when examined under the micro- scope, is found to c6nsist of grains, generally globular or ovoid, sometimes triangular or polyhedral, etc., but all alike in the same species. Each pollen-grain is a mem-. 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 Koehler, August. New York, H. Holt and Company
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