41 



and drainage must be rapid and thorough. The lc;wer margin 

 of the association shows an obvious correlation in space with the 

 drainage system, and is probably determincfl physiologically by 

 the water relation of the plants. 



The ground cover is a close, heavy, matted sod, four to six 

 inches thick, composed apparently of five dominant species of 

 grasses, and, near the end of the dry season in March, a dull 

 grayish green in color. One species only still retained the old 

 culms and inflorescences, but the latter were so badly shattered 

 that we were unable to recognize even the tribe to which it 

 belonged. All the species have matted narrow leaves, and some 

 of them are decidedly pubescent, indicating the xerophytic 

 conditions under which they live during the dry season. 



The secondary species are (in March, at least) exceedingly 

 few in number and show little indication of any vegetative activ- 

 ity. Their usual height is about a foot. The commonest 

 species, Anaphalis brevifolia, has a few spreading branches 

 and is closely gray-pubescent. The association is speckled with 

 them in every direction, and reminds one of the appearance of 

 similar gray plants in the short-grass association of the x\merican 

 prairies. 



Most of the secondary species were completely unrecognizable 

 at the time of our visit. The few that could be identified 

 included the melastome Osbeckia Walkeri, Vernonia Wightiana, 

 the rubiad Heydotis verticillaris , simulating in habit a diminutive 

 yucca, and Pteris aquilina. In general, the composites and 

 melastomes seemed to be most abundantly represented. At the 

 lower margin of the association, an occasional plant of the pros- 

 trate creeping Lycopodium carolinianum appeared, and a few 

 other plants belonging properly to the next association. 



At the bottom of the valleys lies the second association, 

 which may be termed conveniently the wet grassland. It is 

 narrow or wide, depending on the contour of the valley; some- 

 times interrupted, where the drainage has eroded a vertical-sided 

 gorge, sometimes extending in a narrow line up the hills almost 

 to the forest margin, or spreading out below over areas a hundred 

 feet or more wide. Here, again, the dominant species are grasses, 



