81 



Andropogon scoparitts Tridens flavus 



Lcptoloina cognatujii Blymus canadensis 



Paniciini virgatuui Cypcrus Schzveinitmi 



Koeleria cristata Carcx Mtihlenbergii 

 Bouteloua hirsuta 



Others of this nature might be expected. Two other grasses, 

 Paspaluin sctaccuni and Sporoholus cryptandrus, may also occur. 

 They are pioneers, proper to the blowsand and indicative of the 

 probable future succession. 



The secondary species, aside from grasses, consist primarily of 

 perennials and interstitials. Correlated with the removal of the sand, 

 the number of species and individuals of the perennials is small, and 

 they are in general to be regarded as relics rather than proper mem- 

 bers of the association. The species observed are as follows : 

 Tradescantia rcflexa Accratcs viridiflora, var. 



Sisyrincliiiun sp. lauccolafa 



Baptisia bracteata Lithospcnmun Giuclini 



Tcphrosia virgimana Physalis rirgiiiiana 



Lespcdeza capitata Pciitstciiioti hirsutus 



Polygala polygaiiia Solidago nciuoraUs 



CaUirhoe trlangulata Aster linariifol'uis 



Viola pcdata Hclianthus scaberriiniis 



Ace rates viridiflora 



Of these Lcspcdc::a capitata is by far the most abundant, with 

 Hclianthus scaberriiniis and Lithospernuini Gnielini next in impor- 

 tance. Some of the others are represented in single stations, or even 

 by single individuals. 



But one instance was observed of the presence of a mat-plant as a 

 relic ; Opuntia RaHnesqiiii in the Havana area. This is due to the 

 fact that a bunch-grass association with a good development of mats 

 is far less subject to wind action, and consecjuently to succession by 

 the Panicuni pseudopubescens association. 



The exclusion of perennials and mats permits a correspondingly 

 larger representation of interstitial species. These come up from 

 seed late in spring and complete their whole cycle of development in 

 the season when the gentler winds and heavier rainfalls keep the sand 

 in a state of relative cjuiet. The chief species are g'iven in the fol- 

 lowing list : 



Aristida tuberculosa Polygala vcrticillata 



Festiica octoflora Croton glaiidulosus, var. 



Cyperus filicnhnis septentrionalis 



