Enlarged bases of certain trees growing in swamps are very familiar to botanists and naturalists. The spectacular buttresses of cypress offer classical examples of such responses to water. Ordinarily, however, a cypress buttress is not seen in its entirety for the greater part of it is masked by the water, especially in the deeper lakes and ponds. The form, therefore, that the bases assume from the water level downward, unless the water is unusually calm and clear, can only be conjectured by the explorer boating about casually during high-water periods. The prolonged drouths of 1927 and 1931 gave the senior author excellent opportunities to explore dry-footed a number of ponds and lakes in middle northern Florida. Figures 1, 2, and 3 show three distinctive types of buttresses developed by pond cypress, Taxodium ascendens Brongn., when growing in as many different habitats.The first type is very low, wide, and truncated. Harper has described ('02) and published photographs ('OS) taken in Coffee County, Georgia, of bases so flat that one can walk around the tree on them. He associates thesl: with shallow water of rather constant level. Mattoon ('15) also illustrates this type of "low broad base" and correlates it with shallow, non-alluvial swamps. The second type of buttress is plainly conical. In conversation with the senior author, Harper has stated that this form is associated with habitats which fluctuate actively and over a considerable range of depth. The third type appearing like gigantic bottles, previously described by Kurz ('30), is found in ponds or lakes attaining much greater depths than either the habitats of the shallow or conical-based trees.All three of the foregoing types suggest the influence of water level fluctuation in fashioning them; but they hardly indicated, much less proved, the importance of a second factor in buttress development. The junior author's studies of Reelfoot Lake make quite certain the nature of the second factor. Reelfoot Lake, lying just east of the Mississippi in northwestern Tennessee, was formed by land subsidence during the famous New Madrid earthquake of 1811-12. Fuller ('12) has given a comprehensive report on this geological phenomenon. Nelson ('24) gives an admirable popular account of the history of Reelfoot Lake. The catastrophic subsidence referred to above
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