File:Elementary botany (1905) (20536225860).jpg

Title: Elementary botany
Identifier: cu31924000422794 (find matches)
Year: 1905 (1900s)
Authors: Atkinson, George Francis, 1854-1918
Subjects: Botany
Publisher: New York : H. Holt
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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404 RELATION TO ENVIRONMENT. V. Leaf Patterns. MOSAICS, OR CLOSE PATTERNS. 774. \Miere the leaves of a plant, or a portion of a plant, are approximate and arranged in the form of a pattern, the leaves fitting together to form a more or less even and continuous sur- face, such patterns are sometimes termed "mosaics," since the relation of leaves to one another is roughly like the relation of the pieces of a mosaic. A good illustration of a mosaic is pre- sented bv a greenhouse plant Fittonia (iig. 44i). The stems
Text Appearing After Image:
ig- 441- Fittonia showing leaves arranged to form compact mosaic. The netted vena- tion of the leaf is very distinctly shown in this plant. (Photo by the Author.) are prostrate and the erect branches quite short, but it may have quite a wide .s)-steni bv the spreading of the runners; the branches of such a length that tlie leaves borne near the tips all fit together forming a broad surface of leaves so closelv fitted together often that the stems cannot ))e seen. The ad\'antage of a mosaic over a sei)aratc disposition of leaves at somewhat different levels is that the leaves do not shade one another. Were all the light ra)'s coming down at riglit angles to the leaves, there would not Ije any shading of the lower ones, but the oblique ravs of light would he cut off from many of the lea\'es. In the case of a mosaic all the ra\'s of h'glil plav upmi all llic leaves. Some (if the mosai(S wliich can be iibscr\i'i; arc as follcnvs:

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