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Loggerhead Key

plants, trees, suriana, hymenocallis and islands

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LOGGERHEAD KEY.

This is the largest of the Tortugas group and also the highest above sea-level and according to tradition it had in earlier times the largest stand of trees. Old fishermen (and the report was current in the times of the older light-house keepers) state that 75 or 80 years ago this island, as well as Garden Key and others of the group, supported a large stand of old white buttonwood trees, Conocarpus erectus L. These were largely cut down by fishermen, who occasionally camped for perhaps several weeks or months in the Tortugas; fires also are said to have had their share in devastating this old silvan flora. The central group of very old and large buttonwood trees in the parade-ground of Fort Jefferson on Garden Key is the only remnant of this supposed aboriginal silvan flora.

The booby, a kind of gannet, is said to have inhabited these islands, but has disappeared with the passing of the trees. Old fishermen relate that men, armed with clubs, would stealthily creep into the groves of buttonwood at night and kill perhaps hundreds of these birds out of pure wantonness, as they had little or no economic value. The same wanton spirit which eradicated the Conocarpus groves and the "boobies" in these islands has been shown by the people of the region in regard to the manatee, which is now nearly extinct in these waters; the large green and loggerhead tortoises are also fast disappear ing, due to a custom of eating the eggs and killing the females. During the breeding-season of 1916 not over 6 females were reported in these islands as coming in to lay, and two of these were killed after laying and the entire settings of eggs taken, whereas even ten years ago it is said that as many as a dozen females came up on the beach in one night to lay on Loggerhead Key.

The vegetation of Loggerhead is remarkably free from the common tropical weeds when compared, for example, with Garden Key. This is probably because this island has never, since its first permanent occupation 75 years ago, been brought into frequent contact with the mainland by ships, men, or Animals, except for a few months shortly after the Civil War, when a quarantine camp was established for the marines brought over from Fort Jefferson during an epidemic of yellow fever. The only permanent residents now are the keepers of the light house; while the monthly call from Key West of the cutter of the Light House Establishment, which rarely lasts over 2 hours at Loggerhead Key, does not seem to have served for the introduction of homovectant plants.

A glance at the distributional map of Loggerhead will show that two of the four associations mentioned above are represented in the island, the Suriana community predominating and the Opuntia association supplementing it. A photograph taken from the top of the light-house

shows the vegetation to be distributed in sharply defined areas follow ing irregular outlines. It is supposed that some of the central areas now occupied by the Opuntia formation (see plate 3) was cleared of the dense growth of Suriana by the marines and soldiers who camped there during the epidemic of yellow fever mentioned above, but the irregular outline and the isolated patches of Opuntia among the Suriana show that other agencies than man have helped to clear portions of the island.

As remarked before, the Suriana does not withstand a drenching of sea-water very successfully, the tomentum of the leaves holding the water until its toxic effect is produced on the leaf-tissue. The great hurricanes of the past must undoubtedly have had their share in cutting out some of the swathes in the Suriana community. In the list of species and on the map also some large introduced plants appear, which add conspicuous features to the landscape and perhaps have an influence on the native flora by producing shade and conserving water, etc. Examples of these are the coconut palms, the Casuarina trees, the papaws, and the figs planted about the building and gardens of the light-house and laboratory; others are the Hymenocallis, the oleanders and Hibiscus, Thespesia, aloes, yuccas, Pedilanthus, and Asparagus. All of these, but more particularly the coconuts, papaws, casuarinas, and Hymenocallis, have been liberally planted about the laboratory grounds. A noticeable effect of these introduced plants was the increase in the number of plants and the size and vigor of the foliage in Boerhaavia viscosa when it grew under these trees or tangled among the Hymenocallis plants along a concrete walk leading to the wind pump shed at the laboratory. Another example was seen in the greater luxuriance of Chamesyce and Ipomea, when growing near the slight shade thrown by the coconuts, the newer shoots of Ipowea being more slender and tender than when growing in their accustomed habitat on the beach in fierce sunlight. These introduced plants, with the excep tion of the Cocos and Hymenocallis, have been brought in and planted by the Director of the Laboratory and have (plate 4) maintained themselves fairly well in such a difficult environment, although only Casuarina has reproduced and seeded in. This Australian plant seems to thrive remarkably in these islands. The Hibiscus about holds its footing when planted, but Thespesia and Carica seem to decline if not watered artificially.

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