. Lectures on the evolution of plants. Botany; Plants. 68 EVOLUTION OF PLANTS dition between these and the simplest types, like Ecto- carpus (Fig. 16). Among the most characteristic of these larger forms may be mentioned the great bladder-kelps of the Pacific (Macro- cystis, Nereocj'^stis) (Fig. 17), and the smaller Laminarias of the Atlantic. Many of the larger kelps grow where they are exposed to the full force of the heavy surf, and this ac- counts for the tough, leathery consistency of many of them, and the powerful hold- fasts or roots. An examination of the whole class shows that within
. Lectures on the evolution of plants. Botany; Plants. 68 EVOLUTION OF PLANTS dition between these and the simplest types, like Ecto- carpus (Fig. 16). Among the most characteristic of these larger forms may be mentioned the great bladder-kelps of the Pacific (Macro- cystis, Nereocj'^stis) (Fig. 17), and the smaller Laminarias of the Atlantic. Many of the larger kelps grow where they are exposed to the full force of the heavy surf, and this ac- counts for the tough, leathery consistency of many of them, and the powerful hold- fasts or roots. An examination of the whole class shows that within it there has been much such an evolution of the reproductive cells as we have seen in sev- eral groups of the green algse; but this is by no means paral- leled by the vegetative parts, as the largest, and, so far as the plant-body is- concerned, the most specialized Fig. 17. — A young plant of Nereocystis Lutkeana, one of the large kelps, much reduced, showing the holdfast, r, and the float, v, with the large leaves at Its summit; the fully grown plant may reach a length of a hun- dred feet or more; B, the simple uni- locular sporangia, sp, and sterile hairs, or paraphyses, par, much mag- 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 Campbell, Douglas Houghton, 1859-1953. New York, The Macmillan Co. , London, Macmillan & Co. , Ltd.
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Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
