GEOGRAPHY OF CENTRAL FLORIDA 211

 As in the jack-pine and spruce forests of the far north, but unlike anything else in or near Florida, fire sweeps through the scrub about once in the life-time of a pine tree and kills the pines, which however soon come up again from seed. Sometimes two crops of pine of different ages can be seen close together (fig. 31).
 Scrub vegetation indicates very.poor soil, which is usually left uncultivated, but it is utilized along the east coast, as noted in the chapter on soils.
 Cypress ponds (fig. 24). These are a characteristic feature of the pine-barren portions of the coastal plain from North Carolina to eastern Louisiana, and they extend south in Florida to Palm Beach County and the "Big Cypress" of Lee County. There seems to be nothing similar in any other country on earth. In the area under consideration they are very abundant in the flawoods regions (except in the pebble phosphate country), rare, in the lake region, and practically unknown in the others. In northern Florida and neighboring states they usually contain more or less slash pine (Plins Elioffii) or sometimes black gum, but south of Flagler County the pines rarely enter the ponds, and there is commonly a treeless strip a few yards wide around each pond, where the soil is a little too dry for cypress and too wet for the common slash pine of the peninsula (P. Caribaea). In size the, ponds may range from one to a hundred acres or so, and the water may be as much as three feet deep in the larger ones in wet seasons and disappear entirely in dry seasons. The amount of seasonal fluctuation is indicated roughly by the height of the enlarged bases of the trees.
 The pond cypress (Taxodium ascendens, or imbricarium) is usually almost the only tree. Sometimes it grows so densely as to exclude nearly all other woody plants, and sometimes the cypresses are farther apart and there is a dense undergrowth of mostly evergreen shrubs and a few vines, making an approach to the bay type of vegetation. Air-plants of three or four species are often abundant on the trunks and limbs of the cypresses, making a very striking picture. In the shallow water below are a number of herbs almost confined to such situations. A list of characteristic cypress pond plants for the whole State was published in the Third Annual Report (pages 262-263), and that would not require much modification to fit central Florida alone.