The American botanist and florist; including lessons in the structure, life, and growth of plants; together with a simple analytical flora, descriptive of the native and cultivated plants growing in the Atlantic division of the American union . acemosa. 400. The hairs which clothe the epidermis are mere expan-sions of its tissue. They may each consist of a single elongatedcell, or of a row of cells. They may also be simple, or branched,or stellate, or otherwise diversified. 401. Glands are cellular structures serving to elaborate andcontain the peculiar secretions of the plant, such as aromati
The American botanist and florist; including lessons in the structure, life, and growth of plants; together with a simple analytical flora, descriptive of the native and cultivated plants growing in the Atlantic division of the American union . acemosa. 400. The hairs which clothe the epidermis are mere expan-sions of its tissue. They may each consist of a single elongatedcell, or of a row of cells. They may also be simple, or branched,or stellate, or otherwise diversified. 401. Glands are cellular structures serving to elaborate andcontain the peculiar secretions of the plant, such as aromaticoils, resins, honey, poisons, etc. A gland may be merely an ex-panded cell at the summit of a hair, or at its base, and hence 132 PHYSTOLOGICAL BOTANY. called a glandular hair (Labiatse). Or it may be a peculiar cellunder the epidermis, giving to the organ a punctate appearance(leaf of Lemon). Other glands are compound, and either external(Sundew) or internal reservoirs of secretion (rind of Orange), 402. Stings are stiff-pointed, 1-celled hairs expanded at baseinto a gland containing poisonous secretion. An elastic ring ofepidermal cells presses upon the gland so as to inject the poisoninto the wound made by its broken point (Nettle).. 499, Rootlet of ]\[adder, showing cells expanded into fibrillae. 500, Glandular hair of Fraxlnella, sec-tion. 501, Hair of Bryonia, of several cells. 502, Hair of several cells, surmounted by a gland, of An-tirrhinum majus. 503, Sting; of Urtica dioica. 504, Jointed hair of the stamens of Tradescantia. 505,Stellate hair from the petiole of Nuphar advena (magnified 200 diameters—Henfrey). 506, Branchedhair, one cell, of Arabis. 403. Prickles are hardened hairs connected with the epider-mis alone, thus differing from spines, which have a deeper in the Rose. Iteview.—yf\\9X does the Epidermal System includet 396. What is the office of theepidermis? What its cells? 397. What are the stomata? When are they open, andwhen closed ?
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1870
