. Fundamentals of botany. Botany. LIFE HISTORY OF A FERN 159 spores may be formed; a sorus will consist of fuUy lOO sporangia, usually more; 20 is a moderate estimate of the sori on an average pinna; there may be fully so fertile pinnas on one well-developed leaf, and a strong plant would bear 10 fertile leaves. 48 X 100 X 20 X 50 X 10 = 48,000,000. The output of spores on a strong plant in the single season wiU thus, on a moderate estimate, approach the enormous number of fifty millions"- 148. TjT)es of Sporophylls.—In many ferns the leaves serve both vegetative and reproductive function
. Fundamentals of botany. Botany. LIFE HISTORY OF A FERN 159 spores may be formed; a sorus will consist of fuUy lOO sporangia, usually more; 20 is a moderate estimate of the sori on an average pinna; there may be fully so fertile pinnas on one well-developed leaf, and a strong plant would bear 10 fertile leaves. 48 X 100 X 20 X 50 X 10 = 48,000,000. The output of spores on a strong plant in the single season wiU thus, on a moderate estimate, approach the enormous number of fifty millions"- 148. TjT)es of Sporophylls.—In many ferns the leaves serve both vegetative and reproductive functions in about. Fig. 119.—The cinnamon fern [Osmunda cinnamomea), showing foliage leaves and sporophylls. equal degree, as in the case of Polypodium mentioned above. In some species, however, there are two kinds of leaves—one devoted entirely to vegetative functions, and another to the reproductive, or spore-producing function (Fig. 119); between these two extremes aU grades of trans- ition are found (Fig. 120). But however widely the sporo-. 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
