. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. A flower of Sedum, from the side; ^, anther of stamen; C, carpel; F, filament; P, petal; S, sepal. Structure of a Simple Flower. — For the following exercise, the buttercup and Sedum (stonecrop) are good. They may be ob- tained in the fall.^ The expanded portion of the flower stalk, which holds the parts of the flower, is called the receptacle. The green leaflike parts cover- ing the unopened flower are called the sepals. Sometimes the sepals are all joined or united in one piece. Taken tog
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. A flower of Sedum, from the side; ^, anther of stamen; C, carpel; F, filament; P, petal; S, sepal. Structure of a Simple Flower. — For the following exercise, the buttercup and Sedum (stonecrop) are good. They may be ob- tained in the fall.^ The expanded portion of the flower stalk, which holds the parts of the flower, is called the receptacle. The green leaflike parts cover- ing the unopened flower are called the sepals. Sometimes the sepals are all joined or united in one piece. Taken together, they are caUed the calyx. Notice that the sepals come out in a circle or whorl on the flower stalk. How many sepals do you find ? In what respect do they resemble leaves? Are there any evidences as to their use or function ? The more brightly colored structures are the petals. Taken together, they form the co- rolla. The corolla is of importance, as we shall see later, to make the flower conspicuous. Compare the petals and sepals In this flower. Are sepals and petals in any respects like leaves ? A flower, however, could live without sepals or petals and still do the work for which it exists. The essential organs of the flower are within the so-called floral envelope. They consist of the stamens and carpels (or pistils). The latter are in the center of the flower. The structures with the knobbed ends are called stamens. How many stamens do you find, and what is their position ? In a single stamen the boxlike part at the end is the anther; the stalk is called the fila- ment. The anther is in reality a hollow box in which a dustlike material called pollen is produced. It is necessary for the life of the plant that the pollen get out of the anther. Try to find how it gets out. Pistil. — Each carpel or pistil is composed of a rather stout base called the ovary, and a more or less lengthened portion rising from the ovary called the style. The upper end of the style, which
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