. A Manual of botany : being an introduction to the study of the structure, physiology, and classification of plants . Botany. 342 POSITION AND FOEM OF THE tached to the pericarp, pe, by the funiculus, /. The chalaza and hUum are confounded together at ch, the micropyle being at the opposite end. The integuments of the seed, t, cover the embryo with its perisperm, ps; the coty- ledons, c, point to the Mlum and chalaza; while the radicle, r, points to the micropyle, and the embryo is thus reversed or inverted. Again, in an anatropal seed (figs. 589, 590, p. 332), where the micropyle is
. A Manual of botany : being an introduction to the study of the structure, physiology, and classification of plants . Botany. 342 POSITION AND FOEM OF THE tached to the pericarp, pe, by the funiculus, /. The chalaza and hUum are confounded together at ch, the micropyle being at the opposite end. The integuments of the seed, t, cover the embryo with its perisperm, ps; the coty- ledons, c, point to the Mlum and chalaza; while the radicle, r, points to the micropyle, and the embryo is thus reversed or inverted. Again, in an anatropal seed (figs. 589, 590, p. 332), where the micropyle is close to the hHum, and the Kg- 619. Kg. 620. chalaza at the opposite extremity, the embryo is erect or homotropal (S/ioiog, like, and Tgs'jnii, I turn), the radicle or base of the embryo being directed to the base of the seed. In some anatropal ovules, as in Castor oU (fig. 579, p. 329), the exostome is thickened or carunculate, c, and the endostome does not correspond exactly to it, so that the radicle, e r, of the embryo is directed to a point a little removed from the exostome. In curved or campy- lotropal seeds (fig. 455, p. 255) the embryo is folded so that its radicular and cotyledonary extremities are ap- proximated, and it becomes amphitropal (a//-f>i, around, r^B'?rcii, I turn). In this instance the seed may be exalbuminous, and the embryo may be folded on itself (fig. 620), or albuminous, the embryo surrounding more or less completely the perisperm, and being peripherical (fig. 618). In fig. 620 the seed of Erysimum cheiran- thoides is shown, with the chalaza, ch, and the hUum, h, nearly confounded together, the micropyle, m, the embryo occupying the entire seed, with the radicle, r, folded on the cotyledons, c, which enclose the plumide, fl'. Thus, by determining the position of the hilum, chalaza, and micropyle, the direction of the embryo may be known. According to the mode in which the seed is attached to the Fig. 619. Orthotropal seed of Sterculia Balanglias^
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
