. A text-book of botany for secondary schools. Botany. LEAVES 35 light, but they produce leaves reduced in size and without green tissue. Often these scales seem to be merely useless relics (Fig. 64); but sometimes they are used for food storage, as in lily bulbs, onions, etc., which are mostly made up of fleshy scales (Fig. 65). In the scaly buds, so common on shrubs and trees, the overlapping scales are clearly protective structures, and to this end are generally firm and resistant, often coated with resin, the inner ones being frequently clothed with woolly hairs. (2) Tendrils.—The whole le
. A text-book of botany for secondary schools. Botany. LEAVES 35 light, but they produce leaves reduced in size and without green tissue. Often these scales seem to be merely useless relics (Fig. 64); but sometimes they are used for food storage, as in lily bulbs, onions, etc., which are mostly made up of fleshy scales (Fig. 65). In the scaly buds, so common on shrubs and trees, the overlapping scales are clearly protective structures, and to this end are generally firm and resistant, often coated with resin, the inner ones being frequently clothed with woolly hairs. (2) Tendrils.—The whole leaf or some of its branches may develop as tendrils, the latter case being illustrated by the sweet pea (Fig. 32). Ten- drils are sensitive to contact and aid in climbing. Some- times leaves act as tendrils without any modification of the blade, the petiole being sensitive to contact and encircling sup- ports like a tendril, as in the garden nasturtium. (3) Thorns.—Leaves develop- ing as thorns may be observed in the barberry (Fig. 33). In the common locust, acacia, etc., only the stipules develop as thorns. Both tendrils and thorns are also developed as stem struc- tures, being modified branches. (4) Leaves of pitcher-plants.— In these plants the leaves form tubes or urns of various forms, which contain water; and to these insects are attracted and drowned. The common pitcher- plant of the northern States, a Sarracenia, is a well-known. Fig. 32.—Pinnately compound leaf of garden pea, whose ter- minal portion has developed as tendrils. — After Stras- 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 Coulter, John Merle, 1851-1928. New York, D. Appleton
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