94 



Cassia Chamaechrista 

 Sporoboliis cryptandriis 

 Oenothera rhomhipetala 

 Croton glandiilosus, 



var. septcntrionalis 

 Buphorbia Gcyeri 

 Froelichia florid ana 

 Tephrosia virginiana 

 Cy perns iiliculinis 

 Cydoloma atriplicifolinm 

 Festnca octo flora 

 Polanisia graveolens 

 Helianthns lenticularis 

 Hedeovia hispid a 



Euphorbia corollata 

 Mollugo verticiUata 

 PolygoncUa articulata 

 Crotonopsis linearis 

 Linaria canadensis 

 Cristatella Jamesii 

 Monavda punctata 

 Lcpidiuni virginicuni 

 Lcspcdcza cap it at a 

 Strophostylcs hclvola 

 Apocynuui cannabinuin, 

 var. hypericifolium 

 Scntellaria parvnla 



The majority of these 31 species are annuals, and appear also 

 as interstitials in the bunch-grass and Paniciim pseudopubesccns as- 

 sociations. One, Apocynuni cannabinnni, var. hypericifolium, is a 

 perennial, but behaves as an interstitial in this habitat. Its occurrence 

 was noted but once. The three true perennials, Buphorbia corollata, 

 Lespedeza capitata, and Tephrosia z'irginiana, and the one bunch- 

 grass, Sporoboliis cryptandrns, are all more numerous on the de- 

 posits or in other associations, and their presence here is either casual 

 or else indicative of a succession by the deposit association. 



But one species, Aristida tubcrcnlosa, is equally common over 

 the four areas studied. Scarcely a blowout was observed which did 

 not have hundreds of plants of this slender grass growing on the lee 

 slope. The other leading species are more local in their distribution. 

 Diodia teres is particularly characteristic of the Hanover area, is 

 also common, but local, in the Havana area, but was not observed 

 in the other two areas. The Oquawka blowouts are marked especially 

 by C oniniclina virginica and Paspahun sctaceuni, while Ccnchrus caro- 

 linianns is most abundant in the Havana area. 



Excluding the Dixon area, in which there is comparatively little 

 blowing sand, from 17 to 22 of the 31 species occur in each area. 

 Within each area the flora varies from one blowout to another, and 

 a comparatively small portion of the flora appears in any one. Not- 

 withstanding this great local variation between stations, there is no 

 evidence that more than one association exists. The different com- 

 binations of species represent merely alternations in the structure of 

 the association, which are not definite enough to demand classification 

 or description as separate consocies. 



