Nature and development of plants . ia come to lie on the under side of the structure betweenthe finger-like outgrowths, where they are completely hidden andprotected by fringed curtains, the involucre, that hang down fromthe fingers (Figs. 191, 195, A). The antheridia retain their orig-inal position upon the branch, where they appear in cavities, asshown in Fig. 192. The most important and significant departure in MarchanHa isseen in the germination of the gametospore which divides into aninner and outer cell as in Ricciocarpus (Fig. 193, B). The innercell, however, by a series of divisions, f
Nature and development of plants . ia come to lie on the under side of the structure betweenthe finger-like outgrowths, where they are completely hidden andprotected by fringed curtains, the involucre, that hang down fromthe fingers (Figs. 191, 195, A). The antheridia retain their orig-inal position upon the branch, where they appear in cavities, asshown in Fig. 192. The most important and significant departure in MarchanHa isseen in the germination of the gametospore which divides into aninner and outer cell as in Ricciocarpus (Fig. 193, B). The innercell, however, by a series of divisions, forms a rudimentary stalkand the lower part of it, known as the foot, comes into close DEVELOPMENT OF PLANTS 259 contact with the tissues of the plant from which it absorbs nour-ishment (Figs. 193, 194). The outer cell divides, forming aspherical mass of cells that resembles the capsule of of these cells of the capsule develop as spore mother cells,while others, known as elaters, elongate greatly and serve to con-. Fig. 193. Germination of the gametospore: A, section of a maturearchegonium with canal cells dissolved, thus forming a passageway to thelarge female gamete, g. B, sectional view of base of archegonium, show-ing the germinating gametospore in two-cell stage. The perianth, p, isseen growing up about the archegonium. C, later stage in the growth ofthe gametospore. The lower cell shown in B is forming stalk cells, whilethe outer cell has produced densely granular cells that will later by furtherdivision form spore mother cells and elaters. duct the foods absorbed by the foot to the spore mother cells, andfinally they become spirally thickened (Fig. 194, C). During thegermination and growth of the gametospore, a delicate membrane(the perianth) grows up about the archegonium and doubtlessassists the involucre in protecting it against drying winds (; P)- When the spores are mature, the cells of the stalk 260 SPOROPHYTE OF MARCHAXTIA elongate, rupt
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