Text-book of botany, morphological and physiological . rowsin all directions, resulting at an early .period in its differentiation into plerome(///, IV, V, shaded in the drawing), and periblem. The mass of tissue which isproduced from the primary cell of the embryo thus increases rapidly by the multi-plication of its cells, and two large protuberances (F, cc), the first leaves orcotyledons, soon make their appearance one on each side of the apex {s); the L 1 2 5i6 PHANEROGAMS. apex of the stem exists for the present only as the end of the longitudinal axis ofthe embryo; an elevated piece of ti
Text-book of botany, morphological and physiological . rowsin all directions, resulting at an early .period in its differentiation into plerome(///, IV, V, shaded in the drawing), and periblem. The mass of tissue which isproduced from the primary cell of the embryo thus increases rapidly by the multi-plication of its cells, and two large protuberances (F, cc), the first leaves orcotyledons, soon make their appearance one on each side of the apex {s); the L 1 2 5i6 PHANEROGAMS. apex of the stem exists for the present only as the end of the longitudinal axis ofthe embryo; an elevated piece of tissue, the vegetative cone of the stem, is notformed till later deeply enclosed between the cotyledons. The posterior or basalend of the axis of the embryo after the differentiation of its primary meristeminto dermatogen, periblem, and plerome (//, ///, IV), is, so to speak, open aslong as this differentiation has not also taken place in the hypophysis (/z); butfinally it takes place in it also and in such a way (as is shown in Fig. 372, V), that ff 1. Fig 372.—Formation of the embryo of Cap^elld Bursa-pastOyis (after Hanstein); I—VI various stages of development,Vb apex of the root seen from below; i, i, z, 2, the first divisions of the apical cell of the pro-embryo (suspensor),h h the hypophysis, u the pro-embryo, c the cotyledons, s apex of the axis, w root (the dermatogen and plerome areshaded dark). the upper of its two cells breaks up into two layers [K), the outer of which becomescontinuous with the dermatogen of the axis, while the inner layer forms a pro-longation of the internal axial tissue. The low^r cell of the hypophysis {h) dividescross-wise {Vh, seen from below) and may be regarded as a transitional structurebetween pro-embryo and root (appendage of the root) or as the first layer of theroot-cap. Hansteins description of the growth of the root-cap of Phanerogams,confirmed by Reinke\ is of very great value, showing, as may be seen from » Compare also Reinke,
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
