. Nature and development of plants. Botany. DEVELOPMENT OF PLANTS 205 at different levels in the plant world and in groups in no wise connected. We have noted the same state of sexuality in some of the motile green algae, i. e., in Chlamydomonas and in non- motile forms as Hydrodictyon and Ulothrix, and now again in Ectocarpus although these plants are widely separated as far as relationship is concerned and exhibit a marked variation in the development of the plant body. It is also frequently to be noted that plants may get along very well indeed with only a sexual or an asexual method of rep
. Nature and development of plants. Botany. DEVELOPMENT OF PLANTS 205 at different levels in the plant world and in groups in no wise connected. We have noted the same state of sexuality in some of the motile green algae, i. e., in Chlamydomonas and in non- motile forms as Hydrodictyon and Ulothrix, and now again in Ectocarpus although these plants are widely separated as far as relationship is concerned and exhibit a marked variation in the development of the plant body. It is also frequently to be noted that plants may get along very well indeed with only a sexual or an asexual method of reproduction. (b) The Coarser Brown Algae, the Kelps.—Under this head we may consider two groups, illustrated by the kelps and rock- weeds. The kelps are related to Ectocarpus and include the largest and most highly organized forms of all the algae. Indeed some of these forms are quite comparable in size with our shrubs and trees. The Laminarias (Fig. 120, A) of our Atlantic coast. Fig. 120. Three of the larger brown algae: A, Laminaria. B. Lessonia. C, Macrocystis. have stalked blades ten to twenty feet long. The great bladder kelps of the Pacific, Nereocystis and Macrocystis, attain great dimensions, the latter genus reaching a length of 500 to 900 feet and Lessonia with trunk-like stems and leaf-like segments forms veritable submerged forests in the Antarctic Ocean (Fig. 120, B, C). These highly organized plants, however, do not show any advance in sexual reproduction over the simplest form noted in Ectocarpus. Much attention has been directed to the kelps. 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 Curtis, Carlton Clarence, 1864-1945. New York, H. Holt
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