FREE INSTITUTE OF SCIENCE 



77 



VEGETATION OF SOUTH FLORIDA 



trees separated by labyrinthine channels of salt water, so perplexing in their 

 ramifications that no surveyor has even attempted to map their position. As 

 the mangrove trees are invading constantly fresh territory, these bays, which 

 probably existed when the earliest maps were made, have been invaded gradu- 

 ally until their original outline has become indefinite.* As bays, they no longer 

 exist, for a tree-top observation of Dr. John K. Small from the extreme western- 

 most everglade key failed to note the presence of any open water where 

 White Water Bay should be. As names on the map, they have been copied by 

 each compiler, so that no two maps agree as to the exact shore line of these 

 so-called bays. The probable correct character of them is shown on the phy to- 

 geographic map which accompanies this monograph. At least, the map is a 

 conservative representation of the geography of the southwest coast of the 

 peninsula. 



Low mangrove thickets extend up the Caloosahatchee River some distance 

 above Ft. Myers, where the river narrows just below Olga. Here in the river 

 are several islands with mangrove vegetation gradually blending with flat 

 areas covered with cat-tail, Typha angustifolia L. About here the red-man- 

 grove, Rhizophora mangle L., loses its hold in competition with river-bank 

 plants controlled by fresh water. The mouth of the Caloosahatchee River is 

 filled with low mangrove islands, and as previously mentioned low thickets of 

 these trees extend north as far as Tampa Bay. Along the protected bays 

 and lagoons formed by the outlying sand keys a dense fringe of mangroves is 

 found, which continues with but slight interruption to the southern end of 

 Charlotte Harbor.f 



Physiognomy of Mangrove Vegetation and Constituent Plants. Mangrove 

 vegetation seen from the water surface along which it is found appears as a 

 dark-green, dense thicket of low trees with rounded or spreading tops and with 

 numerous arched aerial roots, which grow downward into the shallow water, 

 or into the flat, muddy bottom where the water is relatively calm, as in lagoons, 

 inlets, bays, and estuaries. The soil, which is muddy, rarely rocky,J is flooded 

 with water either permanently or at high tide. As we have seen in the case of 

 the Miami and Caloosahatchee rivers, mangrove vegetation extends a consider- 

 able distance inland. The aerial prop roots of the red-mangrove are character- 



* Sanford, Samuel: Second Annual Report, Fla. State Geologic Survey: 194. 



t Cf. Heilprin, A.: Exploration on the West Coast of Florida, Proc. Wagner Free Institute 

 of Science, 1887. 



J Dr. Roland M. Harper has seen Rhizophora on the exposed rocky shore of Lower Matecumbe 

 Key, but its roots had a hard time in getting a foothold in the rock. 



