. Fundamentals of botany. Botany. CALAMITES AND LYCOPODS 373 gametophytes may ultimately produce antheridia, and the male ones, archegonia. It is of interest to note that some of the fossil relatives of the modern horsetails were heterosporus. The structure of the spores is unusual in that they bear four ribbon-like appendages {elaters), formed from the outer wall, and closely coiled around the spores (Fig. 267).. Fig. 269.—Equisetum palustre. Portion of a male prothallus, bearing antherida; a, b, c, three antheridia in successive stages of development; a, empty; sp, escaping sperms and sperm-
. Fundamentals of botany. Botany. CALAMITES AND LYCOPODS 373 gametophytes may ultimately produce antheridia, and the male ones, archegonia. It is of interest to note that some of the fossil relatives of the modern horsetails were heterosporus. The structure of the spores is unusual in that they bear four ribbon-like appendages {elaters), formed from the outer wall, and closely coiled around the spores (Fig. 267).. Fig. 269.—Equisetum palustre. Portion of a male prothallus, bearing antherida; a, b, c, three antheridia in successive stages of development; a, empty; sp, escaping sperms and sperm-mother-cells; c, antheridium not yet opened; d, initial stage in the development of an antheridium. X about 70. (After Sadebeck.) These appendages uncoil in dry air and recoil with moisture, with a sharp, snapping motion, thus rolling the spores about. The distribution of the spores is accomplished when they are ripe, by the opening of the dry walls of the sporangia. The shrinking of the walls gradually forces out the spores, and by the uncoiling and snapping of the elaters the spores become entangled and held fast to each other in little fiocculent masses. Thus the complete. 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 Gager, C. Stuart (Charles Stuart), 1872-1943. Philadelphia, P. Blakiston's son & co.
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Keywords: ., bookauthorgag, bookcentury1900, bookdecade1910, booksubjectbotany
