. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. SUN- AND SHADE-LEAVES 169 fresher green, owing to little decomposition of the chlorophyll (through the absence of strong light) and the greater translu- cency of the leaf ; moreover, chloroplasts are not infrequent in the epidermal cells ( Bracken). In the case of hairy leaves ( Yellow Deadnettlc, Dog's Mercury) the production of hairs is usually much reduced in the shade-form. A similar difference, between the exposed and sheltered parts of the same plant, is exemplified by the more numerous hairs on
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. SUN- AND SHADE-LEAVES 169 fresher green, owing to little decomposition of the chlorophyll (through the absence of strong light) and the greater translu- cency of the leaf ; moreover, chloroplasts are not infrequent in the epidermal cells ( Bracken). In the case of hairy leaves ( Yellow Deadnettlc, Dog's Mercury) the production of hairs is usually much reduced in the shade-form. A similar difference, between the exposed and sheltered parts of the same plant, is exemplified by the more numerous hairs on the stem-leaves as compared with the radical leaves of species having rosettes. In the Meadowsweet (Spircea iilmaria) the lower leaves, protected. Fig. 88,—Transverse sections of the sun- (A) and shade- (B) leaves of the Yellow Deadnettle (Lamiitm Galeobdolon), on the same scale, , intercellular spaces ; p., palisade tissue ; s., stoma (in A, cut longitu- dinally) . among the herbage, are smooth and green on the underside, whilst the corresponding surface in the exposed upper leaves is of a greyish tinge owing to the downy felt of hairs. The cuticle and outer epidermal walls of the shade-forms are thinner than in the sun-forms, a feature which can be related to the greater humidity of the air. A comparison of strips of epidermis from the two kinds of leaves shows that the vertical walls of the epidermal cells tend to be straighter in the sun-form where the leaves are thicker (cf. p. 93). The palisade cells (Fig. 88, p.) are shorter and the number of palisade layers, as compared with lea^•es growing in bright light, exhibits rcduc-. 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 Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. London, G. Bell and sons ltd.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
