Outlines of Lessons in Botany, Part I; from Seed to Leaf by Jane H. Newell
page 92 of 105 (87%)
page 92 of 105 (87%)
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acuteness that children are apt to develop so inconveniently to their
teacher, they triumphantly refuted my statement that it was one leaf, by pointing to the stiples. There was no getting over the difficulty; and although I afterwards explained to them about the position of the buds, and showed them examples, they clung with true childlike tenacity to their first impression and always insisted that they could not see why each leaflet was not a separate leaf.] An excellent way to show the nature of compound leaves is to mount a series showing every gradation of cutting, from a simple, serrate leaf to a compound one (Figs. 24 and 25). A teacher, who would prepare in summer such illustrations as these, would find them of great use in his winter lessons. The actual objects make an impression that the cuts in the book cannot give. [Illustration: FIG. 24.--Series of palmately-veined leaves.] [Illustration: FIG. 25.--Series of pinnately-veined leaves.] Let the pupils compare the distribution of the veins in their specimens. They have already distinguished parallel-veined from netted-veined leaves, and learned that this difference is a secondary distinction between monocotyledons and dicotyledons.[1] The veins in netted-veined leaves are arranged in two ways. The veins start from either side of a single midrib (_feather-veined_ or _pinnately-veined_), or they branch from a number of ribs which all start from the top of the petiole, like the fingers from the palm of the hand (_palmately-veined_). The compound leaves correspond to these modes of venation; they are either pinnately or palmately compound. |
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