67 



collect under the bunches, aiding in the soil formation, and even the 

 narrow strips between the bunches are frequently covered with dead 

 leaves. On the small open spots are mats of Antennaria sp. and 

 Selaginella rupcstris, often growing" together, and as the Selaginella 

 dies out in the middle of the mats a brownish moss comes in. The 

 result is that there is absolutely no chance for the sand to blow and 

 humus can form rapidly. The surface sand is dark brown in color, 

 somewhat loamy in texture, and partially coherent because of the 

 mass of rootlets in it. This condition continues to a depth exceed- 

 ing ten inches (25 cm.). Of the grasses mentioned, Panicuin 

 pseiidopuhescens, often so abundant in the consocies, is cpiite scarce, 

 because of the absence of flat bare sand areas on which its decumbent 

 bunches may spread. Boutdoua hirsuta is also scarce for the same 

 reason. It grows in small tufts two to four inches (5-10 cm.) high 

 on the mats of Sclagiiicllo. The presence of Panicuin Scribuerianum 

 is of interest, since it occurs only in the densest growth of bunch- 

 grass. Thirty-one secondary species occur in various degrees of 

 frequency. Ten quadrats of four square meters each were examined, 

 and the numeral following" each plant name indicates the number 

 of quadrats in which the species occurred. Eleven species, without 

 numbers, did not appear in the quadrats, but were found elsewhere 

 in the consocies. The secondary species are as follows. 



Perennials : 

 Bqiiisctiim hycuiale, 



var. 'uitcnncdiuvi (2) 

 ?oa pratensis 



Pctalostcinuni purpurcuni (i) 

 Tephrosia z'irginiana (4) 

 Polygala polygama 

 Biiphorbia coroUata (4) 

 Viola pcdata ( i ) 

 Callirh e f riang ulata ( 7 ) 

 Lithospennuin Gmelini (2) 



Mats: 



Selaginella rupcstris (8) 

 Opuntia Rafincsqim (i) 



Interstitials : 

 Fcstuca octoflora 

 Chenopodium album 

 Arabis lyrata (i) 



Acerates viridiflora, var. 



lanccolata ( 1 ) 

 Physalis virginiana 

 Aster sericens ( i ) 

 Aster linariifolius (8) 

 Aster sp. 



Hclianthus scabcrrimus 

 Coreopsis palmata (2) 

 Artemisia caudata (i) 



Antennaria sp. (6) 



Hedeo ma h isp id a 

 Linaria canadensis 

 Specularia perfoliata 



(0) 



