382 IN LOiVER FLORIDA WILDS 



the most constant vigilance on the part of the cul- 

 tivator can keep them from taking full possession. 

 Their seeds, like those of most weeds, germinate 

 during damp weather by merely being in contact 

 with the surface of the soil, in fact if they are 

 buried a couple of inches they will not grow. So 

 omnipresent are these pests about our homes that 

 they seem to be an example of the "survival of the 

 unfit." One of the sumacs {Rhus obtusifolia) is 

 often seen as a shrub in the pineland and along 

 the edges of hammocks, but in cultivated ground 

 it becomes a small tree, propagating itself rapidly 

 by underground runners and becoming not merely 

 a nuisance but a menace. The same is true of the 

 common and widely distributed woodbine {Ampe- 

 lopsis quinquefolia) and a grape {Vitis munson- 

 iana) both of which grow in the edge of hammocks 

 but are spreading alarmingly in tilled ground. 

 These are doubtless kept within bounds in a wild 

 state by forest fires. They bear fruit much more 

 abundantly where the other wild vegetation is 

 kept down, and the birds carry and drop their 

 seeds everywhere. 



There are several plants which are naturalized 

 here from the tropics that come up and flourish 



