Excerpt from Variation and Differentiation in Ceratophyllum Ceratophyllum is in many respects a very favorable form for the study of such problems as those outlined. It usually occurs in great abundance wherever it is found at all, and, being a widely distributed plant, can easily be obtained from a variety of habitats. Furthermore, the individual plant attains to a large size, which is very important for work on intra-individual variability. The plant is comparatively simple in structure and presents characters easily capable of quantitative deter mination. It would, in fact, be almost ideal for an investigation of this kind were it not for the fact that, as will be shown later in the paper, the differences produced in the form of the plant by different environ ments are not very marked. Ceratophyllum appears to be a much less plastic form than many of the land plants. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.