. British plants : their biology and ecology. Plants; Plant ecology. 42 BRITISH PLANTS lignified walls, non-living, and containing only air. The cells are cemented together in sheets and columns, and form very effective screens between the living cells filled with water and the external air (Fig. 11). A covering of cork on stems and shoots serves a similar pur- pose. The presence of sclerenchyma in large and long-lived leaves gives them mechan- ical support, and keeps them from being easily torn and injured — , New Zealand flax (Phorm- ium tenax), Aspidistra. 6. Some xerophytes con- tain o
. British plants : their biology and ecology. Plants; Plant ecology. 42 BRITISH PLANTS lignified walls, non-living, and containing only air. The cells are cemented together in sheets and columns, and form very effective screens between the living cells filled with water and the external air (Fig. 11). A covering of cork on stems and shoots serves a similar pur- pose. The presence of sclerenchyma in large and long-lived leaves gives them mechan- ical support, and keeps them from being easily torn and injured — , New Zealand flax (Phorm- ium tenax), Aspidistra. 6. Some xerophytes con- tain oil in their tissues, especially in the leaves. Where present, it un- doubtedly serves to check evaporation. Many strand and semi-desert plants are quite remarkable for their fragrance—, rosemary, bay-laurel, sage, worm- wood, etc. Xerophytic Forms of Leaf and Shoot. The most important are : 1. The Needle-Type, as in the pine. The leaf is evergreen, thick and tough, with a much reduced sur- face ; the internal cells are packed closely together, the cuticle is thick, and the stomata are reduced in number and sunk in pits. 2. The Concrescent Tvpe, as in many cypresses and junipers (Fig. 6). The leaves are thick and evergreen, very small, erect, and fused with the stem along nearly their whole length. There is very little internal air- space, the cuticle is thick, and the surface smooth and Fu>. 10.—Salicomia herbacea (Glass- wort), showing Succulent Stems and Minute Adpeessed Leaves. (Slightly Reduced. After Sowerby.). 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 Bevis, James Frederick; Jeffery, Henry John. London : A. Rivers
Size: 1117px × 2237px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisher, booksubjectplants
