. Botany, with agricultural applications. Botany. REPRODUCTIVE TISSUES 133 stored chiefly in the medullary rays during the previous season; For water storage some plants have special tissues, while others Kke the Cacti store it throughout the plant body. Secretory Tissues. â Secretory tissues, although not so essential and no so common among plants as the other tissues discussed, perform an important function in some cases. Most showy flowers have secreting tissues, known as nectar glands, located at , the base of the corolla or calyx. (Fig. 121.) These glands secrete the nectar, which, by att
. Botany, with agricultural applications. Botany. REPRODUCTIVE TISSUES 133 stored chiefly in the medullary rays during the previous season; For water storage some plants have special tissues, while others Kke the Cacti store it throughout the plant body. Secretory Tissues. â Secretory tissues, although not so essential and no so common among plants as the other tissues discussed, perform an important function in some cases. Most showy flowers have secreting tissues, known as nectar glands, located at , the base of the corolla or calyx. (Fig. 121.) These glands secrete the nectar, which, by attracting insects, aids in securing cross- poUination. Furthermore, honey is made from nectar, and the value of a plant as a bee-plant depends upon the amount and qual- ity of nectar secreted by its nectar glands. On the leaves, stems, or fruits of many plants, such as Mints, Oranges, Lemons, etc., there are glands whose secre- tions give the plant a peculiar fragrance. In the stems and leaves of Conifers occur long tubes or ducts, known as resin ducts, which are lined with secre- tory ceHs that secrete resin from which pine tar, rosin, turpen- tine, and other valuable prod- ucts are made. Much like the Fig. 121. â A Buckwheat flower resin ducts are the milk or lac- with sepak removed from one side tiferous vessels of the Milkweeds *° ^^°7 ^^^ ^^<=*^'' ^^'^'^^ (")â ^^'er (Asclepiadaceae), Spurges (Eu- phorbiaceae), Dogbanes (Apocynaceae), and other plant famihes where milk-like secretions occur. There are numerous secretions many of which, however, are secreted by cells in which secreting is not the special function. Reproductive Tissues. â Reproductive structures are of two kinds, sexual and asexual. Any portion of a plant, as a bud, tuber, stem, or root which may function in producing new plants, is regarded as an asexual reproductive structure. Some plants, as Irish Potatoes, Sweet Potatoes, and Strawberries illustrate, are quite generally propagated asexuall
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1920
