TRANSACTIONS OF WAGNER 



VEGETATION OF SOUTH FLORIDA 



stead, it reaches a height of 2 to 3 m. and on the keys of Florida, as on Big 

 Pine Key, it becomes a good-sized tree. This variation in size is attributed to 

 the influence of the low night temperature in winter and the occasional frost. 

 That these factors, which influence the height of the silver palm, and its 

 northern range, are also active as limiting factors in the distribution of many 

 tropic species is probably true, but in the absence of experimental data, it is 

 perhaps better to advance this view of climatic influence as a provisional 

 hypothesis. 



LONG-LEAF PINE (PINUS PALUSTRIS MILL.) FORMATION 



This formation south of the 27 30' north latitude is a continuation, or 

 southern lobe, of an extensive region called in Harper's report on peat the 

 South Florida Flatwoods ; and in the Tenth Census Report on Cotton Produc- 

 tion by Dr. Eugene A. Smith (VI: 200 (1880) with map opposite page 187) 

 the Long-leaf Pine Region. This region consists of rolling pineland and pine 

 flats, or flatwoods. The rolling pinelands occupy rolling, or gently undulating 

 country sufficiently elevated to secure good drainage. The whole area thus 

 included is about 15,120 square miles. The pine flats, or flatwoods region, 

 follows the direction of the coast margining the rolling pineland by a strip of 

 country of greater, or less width, where the land is low, flat, or badly drained. 

 This region embraces an area about 11,250 square miles in extent. Beside 

 this belt, there is a tract of elevated, flat, wet land on the divide between the 

 Atlantic Ocean and the Gulf of Mexico, which comprises another 2,280 square 

 miles, making for the flatwoods region a total of 13,530 square miles, so that 

 altogether the long-leaf pine, Pinus palustris Mill., covers 15,120+13,530= 

 28,650 square miles of country. 



As far as this vast region of pineland concerns this monograph, it is 

 comprised in the counties of Polk, Manatee, DeSoto and Lee. The more or 

 less sandy soil of the flatwoods is usually underlaid by a clay substratum, or a 

 densely packed sand, which is impervious, and this together with the flat sur- 

 face prevents proper drainage, so that swamps are associated with flatwoods. 

 Throughout the long-leaf pine region, pine barrens occupy the poorer classes 

 of soil. The growth upon these is mostly long-leaf pine, black-jack oak, 

 scrubby oaks of other species. In the flat pine barrens saw-palmetto and 

 gallberry bushes are common. "While the undergrowth of shrubs in the 



