162 IN LOWER FLORIDA WILDS 



lis in the American tropics but is feebly repre- 

 sented with us. When covered with its great 

 heads of white blossoms it is one of our finest 

 ornamentals. Besides this there is the myrtle- 

 of-the-river (Calyptranthes zuzygium), Alvaradoa 

 amorphoides, a few other trees, and a variety of 

 herbaceous plants, including a number of ferns. A 

 lovely Cuban vine (Ipomcea fuchsioides) with large 

 crimson flowers scrambles over the rocks and 

 sometimes the low trees and shrubs. The seeds 

 of all these may have drifted in and gained a foot- 

 hold on the rocky ridge at a time when the great 

 brackish swamp lying to the southeast of Home- 

 stead was wholly under water and before the final 

 elevation of the Upper Keys. 



It is possible that our streams, short and narrow 

 as they are, sometimes act as barriers to north or 

 south migration of certain of our plants. Cera- 

 tiola ericoides and Bejaria racemosa, two large 

 shrubs common in the northern part of the State, 

 extend to Little River but do not occur south of 

 it; nor does the laurel oak which has a somewhat 

 similar distribution. An appreciable number of 

 tropical plants do not pass north of the Miami 

 River, such as Lysiloma bahamensis, Drypetes 



