. A practical course in botany, with especial reference to its bearings on agriculture, economics, and sanitation. Botany. CRYPTOGAMS 349 ar__4i> -- 406. The sporophyte. — The spores found in such abun- dance on the fertile pinnae are all alike, and each one is capable of germinating and continuing the work of reproduc- tion as effectually as the sexual spores of the bryophytes. The fertile frond, or part of a frond, on which they are borne is called a sporophyll (spore-bearing leaf), and the entire plant is the sporophyte, which, with its crop of spores, makes up one generation. It is impo
. A practical course in botany, with especial reference to its bearings on agriculture, economics, and sanitation. Botany. CRYPTOGAMS 349 ar__4i> -- 406. The sporophyte. — The spores found in such abun- dance on the fertile pinnae are all alike, and each one is capable of germinating and continuing the work of reproduc- tion as effectually as the sexual spores of the bryophytes. The fertile frond, or part of a frond, on which they are borne is called a sporophyll (spore-bearing leaf), and the entire plant is the sporophyte, which, with its crop of spores, makes up one generation. It is important to observe that in the ferns and in all pteri- dophytes the sporophyte is the conspicuous and highly organized body that is commonly recognized as the normal growing plant; while with the bryophytes just the reverse holds true, — the sexual generation, or gametophyte, repre- sents the normal plant structure, while the sporophyte is an insignificant appendage which never attains an independent existence. Broadly speaking, in bryo- phytes, it is a spore fruit; in the pteridophytes and spermatophytes a highly developed plant. 407. The gametophyte. — When one of these asex- ual spores germinates, it produces, not a fern plant like the one that bore it, but a small, heart-shaped body like that shown in Fig. 501. Examine one of these bod- ies carefully with a lens. Observe that there are no veins nor fibrovascular bundles, and the whole body of the plant seems to consist of one uniform tissue. Compare it with the forked apex of a branching thallus of a liverwort. Do you perceive any points of similarity ? The two are, in fact, morphologi- cally the same. This heart-shaped body is called a prothal- Hum, and is the gametophyte of the fern. It may be of. 501 502 Figs. 501,502. —Prothallium of a common fern (Aspidium): 501, under surface, showing rhizoids, rh, antheridia, an, and archegonia, ar; 502, under surface of an older gameto- phyte, showing rhizoids, rh, young sporo
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