. Class-book of botany [microform] : being outlines of the structures, physiology, and classification of plants : with a flora of the United States and Canada. Botany; Botany; Plants; Plants; Botanique; Botanique; Plantes; Botanique. THE UONEOUS SYSTEM. l;i9. 587 583 S89 B90 5»T, Rootlet ut Madder, showing cells expanded Into fibrlUie. 538, Glandular luiir of Kruxi- nella, section. 589, Hair of Bryonia, of several cells. 590, Hair of several cells, surinoiinttd by a pland, of Antirrhinum inajus. 691, Sting of Urtica dioica. 592, Jointed hair of the stamens ut Tradescantia. 593, Stellate hair f
. Class-book of botany [microform] : being outlines of the structures, physiology, and classification of plants : with a flora of the United States and Canada. Botany; Botany; Plants; Plants; Botanique; Botanique; Plantes; Botanique. THE UONEOUS SYSTEM. l;i9. 587 583 S89 B90 5»T, Rootlet ut Madder, showing cells expanded Into fibrlUie. 538, Glandular luiir of Kruxi- nella, section. 589, Hair of Bryonia, of several cells. 590, Hair of several cells, surinoiinttd by a pland, of Antirrhinum inajus. 691, Sting of Urtica dioica. 592, Jointed hair of the stamens ut Tradescantia. 593, Stellate hair from the petiole of Nuphar advena (magnified 200 diameters, Ilenfrey). 594, Branched hair, one cell, of Arabia. i: a CHAPTER IV. THE LIGNEOUS SYSTEM 685. Includes the firm structures of roots, stems, and their append, ages, summarily called the wood. ' 686. Structure. The growing rootlet of the germinating plant exhibits under a microscope a nearly uniform mass of cellular tissue. The cells composing it are soft and delicate, with thin, porous walls adapted to absorb moisture, wliich it l;as already begun to do. It grows by the accession of cell to cell through their divi- sion and enlargement at its point, or rather just behind the advance layer which constitutes its cap (pileorhiza § 725. 687. The earliest tissue. The same structure also appears in the expanding cotjdedons and the opening bud of the plumule. At this early stage, tlierofore, all plants alike in all their parts are composed of simple parenchyma. Subsequent changes in structure occur, giving to each tribe its several peculiarities. Still the growing points of the axis, both ascending and descending, advance by the forma- tion of the same tissue, and the vessels, if formed at all, follow a little later. 688. The changes. The rootlet soon becomes a root, assumes a corky layer in- stead of the tender, spongiform epidermis, and ceases to absorb. But new rootlets spring from the radicle, or branch from the axis, whi
Size: 2321px × 1077px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
