Hammocks and Everglades of Florida. 275 



him of home while species of Ludwiga, Utricularia, etc., will 

 also a])pear as old friends. 



When the Everglades aie submerged the danger from 

 freezing is absent; indeed when the water is high even the ad- 

 j« ining pine lands are to some extent protected from frost. Usu- 

 ally, however, the winter is the season for low water so that it 

 happen, that very severe frosts strike the Everglades. Hence 

 it is that strictly tropical forms are largely lacking. 



Here and there where the land is a little elevated, so as not 

 to be so subject to inundation, we find the so-called "islands" 

 covered with a dense growth of trees. The smallest of these 

 islands mav not contain over four or five trees, semi-aquatic in 

 nature, such as Magnolia glauca, Anona glabra, several species of 

 .Sa/i.x:,etc. The larger of these islands may contain a portion that 

 lies permanently above inundation and such portions are usually 

 occupied by true hammocks, bordered, where occasional flood- 

 ing takes place, by a margin of the trees just mentioned. Next 

 to these, where the ground is submerged most of the time, 

 begins the true glade formation. It Is true that there are a 

 few large islands which contain not only hammock but also pine 

 woods. As one glances across the Everglades in some places 

 but few of the islands can be seen, while in other places they 

 are numerous and fairly close together. The ground is not per- 

 fectly level but at more or less frequent intervals are depressed 

 water courses which usually remained filled with water even 

 A^hen most of the area is dry. In these swales the "sawgrass" 

 Cladium effusum, abounds, often growing as tall as a man on 

 horseback. 



The water is clear and abounding in fish, and is, probably 

 on this account, remarkably free from mosquitoes. It is only 

 near the islands, where may be found pools where they may 

 breed, that these pests are really bad. 



These three types of plant formation (not using this word 

 necessarily in its strict ecological signification), hammock, 

 pine land and glade, stand in need of careful ecological investi- 

 gations by precise methods. The writer has outlined 

 conditions as they appear to an observer who has made no 

 instrumental observations to confirm his theories. It is highly 

 desirable that the following problems be studied caiefully: 



