Home >> Papers-from-the-department-of-marine-bio-volume-11 >> 3 Effect Of Temperature to Germ Cell Origin In Vertebrates >> Bush and Long Keys

Bush and Long Keys

island, pool, plants, key and western

BUSH AND LONG KEYS.

The general map of the Tortugas shows that these keys lie slightly west of Garden Key; they are very irregular and are merely narrow strips of sand and ridges of broken corals. During the winter season of 1911-12 the two keys were united by land connections due to storms, so that the outline is now that shown in the distributional map given here. The western end seems to have been the longest elevated out of the sea and supports the most vegetation. The eastern end, however, has tc bear the brunt of the storms and the waves driven in by the prevailing winds, and it is perhaps for this reason that the vegetation is more scant.

Lansing and Millspaugh omitted treating this key as being "so low as to be awash during heavy weather and on this account void of vege tation." If these conditions obtained then the keys must have been built up within a year or two after Lansing's survey, since stem meas urements on some of the Suriana and Tournefortia bushes on this key show them to be almost 12 years old by comparison with plants of the same species from other keys. At any rate, the flora of the island is quite varied and well scattered. Singular as it may seem, it is on this island that more young plants of the red mangrove were found than on any other island in the Tortugas. The south shore has many small seedlings and in a landlocked tidal pool there is quite a clump of older mangroves, which are perhaps 3 or 4 years old and seem to be in a flourishing condition (see plate 6). This pool also contains a con siderable school of small fish and some crabs.

This key is the main nesting-place in the Tortugas for that beautiful and graceful little sea bird, the least tern. All along the beach near the young mangrove plants one stumbles suddenly upon the pairs of speckled eggs, which are very difficult to see as they lie on the bare coral sand. Later the downy chicks are just as difficult to perceive, for at the approach of a stranger they instantly become motionless balls of gray fluff. These least terns are the only birds nesting on the island.

The western shore terminates in a long and narrow northern and a broader and more rounded southern arm. Cakile and Cenehrue incertus grow along the beach at scattered intervals. Back of this and stretching east to the tidal pool is a thick aggregation of Uniola, Tournefortia, Ira, and a little Suriana. East of the pool is a sparse growth of A triplex, Sesuvium, Ipomcea, Calcite, and Alternanthera. South of the pool and in a line with the highest tide-levels are the young Rhizophora seedlings. These seedlings and those about the pool were sufficient to furnish the author with material for physiological work during two seasons at the laboratory and a large number are still left. From the middle of this island to the narrow tidal gut separating the eastern from the western island there is again a mixture of Uniola, Tournefortia, Cenchrus, Atripkx, Sesuvium, and a little &amok. North of the portion across the inlet there is an association similar to this latter group, with the addition of Cyperus brunneus and Chamanyce in large amount.

Following the curve of the western island as it bends south, the vege tation as plotted on the map is very sparse. It is this shore which gets the full sweep of the wind and waves from the northwest. The surface here is mostly heaps of coarsely broken corals and shells, and the plants it supports are a few Sesuvium clumps, Suriana and Tourne fortia bushes, and Cakile. The Suriana is seen only on the leeward side in the more sheltered coves of the shore. In concluding the observa tion on these islands one can only state, in the light of Lansing's survey, which records them as barely emerged from the sea, that all the above vegetation must have appeared on them in the 12 years that have passed since 1904.