. Botany for agricultural students . Botany. 438 PTERIDOPHYTES (FERN PLANTS) tively. The gametophjrtes are small, green, ribbon-like bodies and lie flat on the surface of the substratum. The male gametophyte is the smaller and is one cell in thickness. It bears the antheridia on the tips of the lobes or on the margin. The female gametophyte. Fig. 391. — The gametophytes of Equisetum arvense. A, female gameto- phyte, showing one archegonium (ar) (X about 20). B, male gametophyte with four antheridia shown {$) (X about 40). forms a cushion, a number of cells in thickness, on the upper sur- face
. Botany for agricultural students . Botany. 438 PTERIDOPHYTES (FERN PLANTS) tively. The gametophjrtes are small, green, ribbon-like bodies and lie flat on the surface of the substratum. The male gametophyte is the smaller and is one cell in thickness. It bears the antheridia on the tips of the lobes or on the margin. The female gametophyte. Fig. 391. — The gametophytes of Equisetum arvense. A, female gameto- phyte, showing one archegonium (ar) (X about 20). B, male gametophyte with four antheridia shown {$) (X about 40). forms a cushion, a number of cells in thickness, on the upper sur- face of which the archegonia are borne. The multiciliate sperms, after being set free from neighboring male gametophytes, swim to the archegonia and down their necks to the eggs. The fertilized egg begins to develop immediately and continues until a new sporophyte is formed, and the life cycle is thus completed. Lycopodiales (Club Mosses) About one-eighth of the living Pteridophytes are Club Mosses. They are commonly divided into four groups — Lycopodium Phylloglossum, Selaginella, and Isoetes — but a study of the Lycopodiums and the Selaginellas will serve to give a general notion of the Club Mosses. The Club Mosses, although not Mosses at all, get their name from their Moss-like stem and their club-shaped appearance due to the large terminal strobili which some have. Lycopodium. — There are several hundred species of Lycopo- diums, and they are widely distributed, occurring in both hemi- spheres and from the torrid to the frigid zones. They prefer shady places and some are Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Martin, John N. (John Nathan), b. 1875. New York : John Wiley & Sons, Inc.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1919
