ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 163 



During the summer the climbers become evident, Meni- 

 spermum canadense and Ampelopsis quinque folia especially, 

 while long and slender, almost etiolated shoots of Humulus 

 Lupuhis are frequently met with, as are shoots of Smilax 

 herhacea and S, hispida. Among the herbaceous plants 

 which during the summer are chiefly in evidence must be 

 mentioned Anemone virginiana. Cerastium nutans and (7. 

 viscosum^ already present in spring, persist throughout the 

 summer and autumn. Oxalis cymosa, readily distinguished 

 from 0. stricta by its greater stature, dense pubescence of the 

 stem, its runners, the greater number of flowers in the in- 

 florescence and the failure of the pedicel with the ripening 

 fruit to bend at a sharp angle, makes its appearance during 

 the early summer months. Several Leguminosae occur, 

 chiefly Am/phicarpaea monoica, A. Pitcheri^ Desmodium cus- 

 pidatiim, D. marilandicum and D. rotundijoliumj Lespedeza 

 reticulata and L. violacea. Here and there the graceful stalks 

 of Eryngium yuccaejolium, which occurs in patches, can be 

 seen. Antennaria plantaginijolia, now as wtII as earlier, is 

 in evidence wherever the most adverse conditions prevail. 

 Other Compositae w^hich make their appearance about this 

 time are Actinomeris squarrosa, Cnicus altismnuSj Elephanio- 

 pus carolinianuSy Echinacea purpurea, Helianthus occidentalis, 

 Heliopds laevis^ Lactuca ludoviciana, Prenanthes racemosa, and 

 Verbesina helianthaides , Apocynum cannabinum forms patches 

 here and there. Asclepias purpurascens is represented by 

 isolated individuals. Also in evidence are Echino spermum 

 virginicumy Gerardia tenuifolia^ Phryma lepiostachya^ Man- 

 arda fistulosa, Scutellaria versicolor^ Phytolacca dccandra, 

 Polygonum virginicum, Acalypha virginica and the omnipres- 

 ent Euphorbia Preslii. Frequent is Tradescantia virginica. 

 J uncus tenuis covers the paths. Among the grasses ^5- 

 prella Hystrix, several species of Muhlenbergia, Panicum 

 pliforme and JJniola latijolia are the principal representa- 

 tives. Several ferns have made their appearance by this 

 time, especially Adiantum pedatum, Aspidium acrostichoides 

 and Woodsia obtusa. Pteris aquilina forms large patches. 



The approach of fall is heralded by the blooming of numer- 

 ous Compositae. Of these the more important are, besides 



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