332 Annals of the Carnegie Museum. 



the shelter of driftwood. The society becomes quite conspicuous 

 during the time of blooming of the Lathyrus, when the ends of the 

 branches assume a more or less upright position. The plant blooms 

 continuously from early June to late August or September. 



The Solidago nemoralis society, together with the Aster ericoides 

 society, characterize the autumnal aspect in the lakeward half of the 

 habitat of the formation. These societies are usually associated with 

 the Panicum-Arteviisia consocies. There is often a distinct zonation 

 in the distribution oi Xht Solidago nemoralis, it forming a rather broad 

 band just outside of the zone of cottonwoods, the latter forming the 

 outer boundary of the lagoon vegetation. The only plausible explana- 

 tion suggesting itself is that there may be more suitable conditions of 

 moisture at these places, although the surface of the sand-plain is 

 usually at the same elevation as farther back in the Paniaivi- Artemisia 

 habitat. 



Secondary Species of the Fanictifu- Artemisia Formation. — 



Euphorbia polygonifolia, Onagra biennis^ 



Gnaphaliiimpolycephalum, Onagra Oakesiana, 



Cenchrus caroliniamis, Lupinus perennis, 



Cypa-ns Sclnueinitzii, Polygala verticillata, 



Cy penis Ji licit Im is, Moehringia lateriflora^ 



Arenaria serpyllifolia, Panicum Scribnerianiim, 



Asclepias Syriaca, Lithospermum Gmelini, 



Salix syrticola, Fragaria virginiana, 



Prunus p'umila, Psilocybe ammophilus, 



Geaster hygrometricus, Marasmius sp. 



The distribution of the secondary species among the different con- 

 socies is mainly as follows, most of the species exhibiting a preference 

 for some one particular consocies : 



In the Pafiicujn- Artemisia consocies — 



Euphorbia polygonifolia, Gnaphaliian polycephalum, 



Onagra biennis, Cenchrus caroliniamis, 



Onagra Oakesiana, Cyperus Sclnveinitzii, 



Polygala verticillata, Moehringia lateriflora, 



Arenaria serpyllifolia, Salix syrticola, 



Prunus pumila. 



