. Botany for academies and colleges: consisting of plant development and structure from seaweed to clematis. Botany; 1889. Flo., 189.—A, vert. sec. of fr. of Dock (Rmnex). B, do. of fr. of night (MirabilU jalapa). C, do. of sd. of CUfus gymp/iitifolius. D, do. of sd. of Primrose {Primula elalior): «, embryo; h, hilum; f, tegmen abd testa; Py perispeiTQ. 307. The position of the embryo in regard to the Seed.—The three typical positions of the ovule being known, we have the following positions for the embryo: I. Ovule orthotropous, embryo nraiifropoas/ that is, the radicle and microp
. Botany for academies and colleges: consisting of plant development and structure from seaweed to clematis. Botany; 1889. Flo., 189.—A, vert. sec. of fr. of Dock (Rmnex). B, do. of fr. of night (MirabilU jalapa). C, do. of sd. of CUfus gymp/iitifolius. D, do. of sd. of Primrose {Primula elalior): «, embryo; h, hilum; f, tegmen abd testa; Py perispeiTQ. 307. The position of the embryo in regard to the Seed.—The three typical positions of the ovule being known, we have the following positions for the embryo: I. Ovule orthotropous, embryo nraiifropoas/ that is, the radicle and micropyle turned from the hilum (Fig. 189, A); II. Ovule anatropous, embryo homotropous; that is, the radicle and micropyle turned towards the hilum (Fig. 193, B); III. Ovule cam- pylotropous, embryo amphitropous, or bent (Fig. 189, B). IV. The embryo is heterotropous when, from the unequal growth of the seed- coats, neither extremity corresponds to the hilum, and the radicle no longer points to the micropyle. This unusual form is found in the Primrose (Fig. 18fl, D), in which the axis of the embryo is parallel to the plane of the hilum ; and in the Grasses (Fig. 6, A), in which it is oblique. The radicle is in these cases termed excentrie. 308. The embryo is awUe when its axis corresponds with the axis of the. whether it be straight (Fig. 189, A) or curved (Fig. 189, C); it is peri- pheric when it follows the periphery (circumference), as in the Pretty-by-night (Fig. 189, B); it is <mns- verse when at right angles with the axis (Fig. 189, D). 309. The Radicle and Caulicle are usually small. Very often, however, the caulicle is conspicuous. In the Pines (Fig. Tig. 190 —A, emb. of Pondweed (F^tamogelon perfolialus) ; r, radicle ; t, caulicle ; c, cotyle- don ; g, plumule. B, emb. of South American Butternut (Caryocar butproB7nn, Pekea butyroaa). C, emb. of Dodder (OusctUa Epilimum).. Please note that these images are extracted from scanned page images that may have been digi
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