PRELIMINARY REPORT ON PEAT. 233
The salt marshes of northern Florida are not very extensive
-usually not more than a mile in width-and they differ very little from those of adjoining states. The following list of salt marsh plants is compiled from notes made along the coast in the vicinity of Fernandina, Mayport, New Smyrna, Titusville, Fort Myers, Punta Gorda, Cedar Keys, and Apalachicola.

SHRUBS
Avicennia nitida (black mangrove) Iva frutescens Laguncularia racemosa (white tnaiigrove or buttonwood)
HERBS
Spartina glabra (marsh grass) Juncus Roemerianus (rush) Batis maritima Salicornia ambigua

Lycium Carolinianum Baccharis halimifolia Conocarpus erectus (buttonwood) Baccharis angustifolia
Distichlis spicata? (a grass) Limonium Nashii Acrostichum aureum? (a fern)

North of latitude 290 the bulk of the salt marsh vegetation consists of the first two herbs named, the second usually in less salty situations than the first. Southward the mangroves and buttonwoods become more and more prevalent, until by the time latitude 260 is reached the marshes are completely replaced by mangrove swamps.
The following plants have been noticed in a mangrove swamp on Biscayne Bay near Lemon City, which is probably fairly typi.. cal of all such places in South Florida:

TREES
Rhizophora Mangle (red mangrove)
Conocarpus erectus (buttonwood)

WOO
Dalbergia Brownei
Acrostichum aureum? (a fern) Hymenocallis? (spider-lily)

Crescentia cucurbitina (calabash
tree)
Coccolobis uvifera (sea grape)

DY VINES
Rhabdadenia biflora
HERBS
Tillandsia Balbisiana (air-plant)

Salt marsh peat or muck contains too much mineral matter to be of any value for fuel, and it is usually very shallow besides. That of mangrove swamps is probably purer and deeper, on the average, though we have as yet little accurate information about it. (See analysis under miscellaneous No. 7.) In some parts of the world salt marshes are diked and ditched and thereby made available for cultivation, but this is an expensive process, profitable only where the population is dense enough to put high values on every class of land.