. Textbook of botany. Botany. THE BRACKEN FERN 109 135. Relatives of the Ferns: Water Fems. â With the true ferns, of which about four thousand species are kno^ii, and which include the brake and the others that have been mentioned, are grouped about eight hundred other species of plants whose relationship to the fems is more or less close. AH of these plants resemble true fems in the fact that their asexual generation is a large, highly de- veloped plant, their sexual gen- eration being small and incon- spicuous. The Ti-'ater ferns are a small group, living either on mud or on the surface of
. Textbook of botany. Botany. THE BRACKEN FERN 109 135. Relatives of the Ferns: Water Fems. â With the true ferns, of which about four thousand species are kno^ii, and which include the brake and the others that have been mentioned, are grouped about eight hundred other species of plants whose relationship to the fems is more or less close. AH of these plants resemble true fems in the fact that their asexual generation is a large, highly de- veloped plant, their sexual gen- eration being small and incon- spicuous. The Ti-'ater ferns are a small group, living either on mud or on the surface of bodies of water. Their spore sacs are formed inside a hard, nut-like structure. The spores are of two kinds : one kind, which is small, develops into a small male plant that bears antherozoids; and the /'X â ^\'.: other kind, much larger, develops r~ ^ \r â , fiG. 60. â Marsilea, one of mto a female plant that produces the water fems. This plant eggs. lives in verj- wet places, usually 136. Horse-tails. âThese, like on-mud the stem creeping along ' the surface. Growing on the the brake, have an underground lower part of the left-hand leaf stem. The stem sends up erect are two nut-like bodies. It is branches, whose appearance gives ^ ^^^^ '^"' "-^^ ^P°^^ °^ ^^ ' '^'^ ° plant are borne. the plant its name. The lea^'es are very small scales which grow in circles upon the branch; the branch is green, and its cells manufacture most of the plant's carbohydrate food. The upright branches have a hard, rough surface, and some of the larger species are called "scouring rushes," from the use to which they were formerly put. The spore sacs are borne on leaves of a special form which are crowded together at the upper end. 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 Allen, Charles E.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1917
