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FREE INSTITUTE OF SCIENCE 
VEGETATION OF SOUTH FLORIDA 
117 
It will be noted that five of the species enumerated above have been placed 
as both water and animal distributed. With abundance of water, as in times 
of inundation, they are carried by water currents; with a less amount, or no 
water at all, they are probably carried by animals. A consideration of four 
of these plants follows. The saw-grass, Cladium effusum, has obovoid achenes, 
somewhat corky at the summit. The buttonbush, Cephalanthus occidentalis, 
has small fruits at length splitting from the base upward into two to four 
closed, one-seeded portions. The false loosestrife, Isnardia natans, has a many- 
seeded capsule, while the mermaid-weed, Proserpinaca platycarpa, has a bony, 
three-angled, three-seeded, nut-like fruit. Where the water is in motion, these 
plants, along with Sagittaria lancifolia, undoubtedly have their fruits distributed 
by water currents, and perhaps they have been carried from banana hole to 
banana hole in seasons when the pineland was flooded with water, or they have 
fallen to the mud of these shallow water pools and have been carried away 
incased in the mud on the feet, beaks, and feathers of ducks, herons, swal- 
lows, and other frequenters of such wet places. 
HAMMOCK VEGETATION 
The examination of the vegetation of the banana holes has suggested the 
possible origin of the hammocks which form such a conspicuous element in 
the landscapes of South Florida. The moisture content of the soil plays a 
most important part in the distribution of the plants. The typic everglade 
species are aquatic plants; the typic pineland species grow in extremely dry 
soil during the dry season, while the vegetation of the banana holes and 
hammocks is decidedly mesophytic, but the character of the hammock is 
conditioned upon the water content of the soil. We can distinguish, therefore, 
two kinds of hammocks, viz., high hammocks (Plate V, Fig. 2) and low ham- 
mocks (Plate VI, Fig. 2). The high hammocks are found under the conditions 
of soil and surface described in the foregoing paragraph. The low hammocks 
are those which occur along the margins of many lakes and streams (Plate VI, 
Fig. 1) and in some of the low swampy areas not connected. with any running 
water or lakes. These low hammocks appear to have generally more sandy 
soil than the high hammocks. 
