181 



eral stems in a cluster ascending from a common center, and 

 while of little importance in holding the sand they frequently 

 collect considerable quantities about their bases. 



No attempts have been made toward controlling the move- 

 ment of the sand and rendering it available for agricultural 

 purposes, but much could be accomplished in that direction. 

 Hedges have been planted in some places, and thickets of plum- 

 trees have been allowed to grow between cultivated fields and 

 sand-hills. The Lombardy poplar (PL XX., Fig.l) might be used 

 with good results, as it thrives on the sand and spreads rapidly 

 by its long underground roots. 



List of the Plants Observed. * 



PoLYPODIACEiE. 



Pteridium aquilinum (L.) Kuhn. 



Equisetace.e. 

 Equisetum, arvense L. 

 Equisetum robustum A. Br. 



Gr AMINES. 



Andropogon seoparius Michx. 

 Andropogon furcatus Muhl. 

 Sorghastrum avenaceum (Michx.) Nash. 

 Paspalum setaceum Michx. 

 Syntherisma Miformis (L.) Nash. 

 Panicurn cognatum Schultes. 

 Panicurn virgatum L. 

 Panicurn sp.f 



Chmtochloa viridis (L. ) Scribn. 

 Cenchrus tribuloid.es L. 



* Only those species of spermatophytes and pteridophytes which grow on the 

 sand prairies or in the black-jack forest proper, without a covering of leaf-mold, have 

 been included in this list. Some additional species have been reported by Patterson 

 ('76) and McDonald ('00). The nomenclature followed is essentially that of Britton's 

 Manual. 



t Abundant on the bunch-grass prairies and of sparing occurrence in t lie black- 

 jack; conspicuous and well marked by the dense tufts with the crowded, almost fas- 

 tigiate, ascending leaves. The primary panicle fruits in July, and the spikelets have 

 nearly all fallen off when the secondary panicles appear, in the middle of August. 

 The specific identity of the plant is in doubt. 



