72 Lloyd and Tracy: The insular Flora 



In the basins one 



Hy 



drjcotyle being the most constant element. The plant has pros- 

 trate buried stems and only the leaves and inflorescences appear 

 above the surface. The petioles are vertically placed and the pel- 

 tate leaf-blades are also strictly vertical, although no orientation 

 was observed. Mollugo verticillata is to be found here also. 



In the second place the surface may be raised locally into 

 dunes of usually inconsiderable size. The dune formers are the 

 grasses on the one hand [Panicum repens and P. halopliihtm) and 

 chiefly two perennials, Iva imbricata and Serenoa serrulata, which 

 here grow in symmetrical cespitose clumps and gradually collect 

 about their bases a dune upon which they raise themselves above 

 the general level, and so become raised upon a pedestal of sand. 

 For this reason the name pedestal dune appears to be appropriate 

 to this dune form. The absence of strong continuous winds may 

 account for the ability of these plants to act in this manner. 



Extending between the elevations and depressions are more or 

 less level reaches where a number of plants grow whose form does 

 not favor the accumulation of sand about them, plants namely 

 which do not tend to produce a network of stems, such for ex- 

 ample as some sedges (Scirpus Americanos, Cyperus cylindriais). 

 There occur also a kw small plants of the radiant type and some 

 -asses (Diodia teres, Sesuvium, Syntherisma fimbriating S. fiH- 

 rms, Cenchrus incertus, C. tribuloides, Euphorbia cordifolia). 

 rhysahs angustjfolia is also frequently met with. 



The second type of sand plain referred to above may be desig- 

 nated as the open, grass plain, characterized as it is by a plant 

 covering of a large number of herbaceous species of low stature 

 among which the grasses greatly predominate. Some of the 

 grasses however, are of large size, Chaetochloa magna and Uniola 

 pamculata for example. The other prominent feature is effected by 

 a heavy growth of slender vines {Vigna glabra, Clitoria mariana), 

 sometimes so dense as to cover the other vegetation out of 

 sight, and covering considerable area. On the whole the condi- 

 tions m this type of sand plain are decidedly mesophytic as com- 

 pared with the beaches and other formations here described, 

 because of the dense covering of plants and because also of the 

 much less salt content of the soil. Two species of Commelwa, 



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