. Class-book of botany : being outlines of the structure, physiology, and classification of plants ; with a flora of the United States and Canada . Botany; Botany; Botany. THE TissrrES. 135 Such combinations are cglled tissues, which we may describe irad«r foar general names or types : I. Cellular tissue (Parenchyma) : II. Fibrous tissue (Plkurbnchyma) ; III. Vascular tissue (Trachenchyma) ; IV. Laticiferous tissue (Cienohyma). 664. Parenchyma, composed of spheroidal cells, is the most com- mon form of tissue, no plant being without it, and many, especially of the lower orders, being entirely
. Class-book of botany : being outlines of the structure, physiology, and classification of plants ; with a flora of the United States and Canada . Botany; Botany; Botany. THE TissrrES. 135 Such combinations are cglled tissues, which we may describe irad«r foar general names or types : I. Cellular tissue (Parenchyma) : II. Fibrous tissue (Plkurbnchyma) ; III. Vascular tissue (Trachenchyma) ; IV. Laticiferous tissue (Cienohyma). 664. Parenchyma, composed of spheroidal cells, is the most com- mon form of tissue, no plant being without it, and many, especially of the lower orders, being entirely composed of it. Numerous varieties occur according to the forms of the cells and their closeness of contact, intermediate between the following extremes, 1, when there are copious intercellular spaces, the cells slightly touching, and being (a) roundcil. or (6) lobed, or (c) stellate ; 2, when the cells are crowded, leaving uo intercellular space and being (d) prismatic, or [e) polyhedral, or (/) ir- regular. 665. Examples of these tissues are found (a) in the pulp offruits, in newly-formed pith, and in all young growths; (6) in the lower stratum of leaf-tissue ; (c) in the pith of rushes and other aquatic plants; (d) in the herbaceous sterna of Monocoty- ledons ; (e) everywhere, but well observed in full-formed pith; (/) abundant in all the soft, fleshy parts of plants. 666. Pleorenchyma is composed of elongated cells cohering by their sides in such a way that end overreaches end, forming a continuous _;J6re. Two varieties are noticed (a) toood- Jibre, with cells of moderate length, remarkable for its firmness, the main constituent of the stems and trunks of the higher plants'; (6) liber, with very long attenuated cells, the substance of the inner layers of bark, remarkable for its tenacity, especially in flax, hemp, linden. 66'7. The pitted cells (§ 650) constitute a singular variety of wood-fiber, common in pines, firs, etc. That mysterious double ring which encircles each
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Keywords: ., bookcentury1800, bookdecade1860, bookpublisher, booksubjectbotany
