ECOLOGICAL CROSS SECTION OF THE MISSISSIPPI. 



175 



canescens 



are 



development till late summer. While several, such as 

 Capsella Bursa-pastoris^ Tri folium repens and Achillea Mille- 

 folium produce flowers during the spring months, chiefly an- 

 nual species are to be found in bloom at this time. The drier 

 places are occupied by Viola Rafinesqidij Plantago virginica 

 and Antennaria plantaginifolia. Where the ground is very 

 moist one flnds Myosurus minimus. Other species now ap- 

 pearing and flowering are Lepidium virginicuvi^ Sisymbrium 



Helianthemum canadense, Cerastium viscosum^ 

 Polygala verticillata and Androsace occidentalis . Rosettes 

 of fall-blooming species bjgin to develop, such as those of 

 Lactuca Scariola, L. Scariola integrata, and VerhascumBlattaria, 

 Plantago patagonica aristata^ P. pusilla and P. RugelH 

 frequent. Rumex Acetosella occurs everywhere as do rosettes 

 of Rumex ohtudfolius. Allium cernuum sometimes covers 

 large patches. To these, the summer months add Sisym- 

 brium officinale^ Hypericum maculatum, several Leguminosac, 

 especially Cassia Chamaecrista, Lespedeza capitata, Psoralea 

 tenuiflora and Stylosanthes elatiovy Diodia teres, Apocynum 

 androsaemifolium, Asclepias tuber osa and A. verticillata j 

 Physalis angulata, Isanthus caeruleus and Sisyrinchium an- 

 ceps. Abutilon Avicennae, Datura Tatula, occasionally also 

 the white-flowered D. Stramonium and the brilliant red shoots 

 of Phytolacca decandra elevate themselves above the rest of 

 the vegetation as do the flower stalks of Oenothera biennis, 

 0. biennis muricata, Verbascum Thapsus and V. Blattaria. 

 At this time too the Corapositae have reached and in some 

 cases passed their full rosette growth, though late summer 

 and early autumn find them at their zenith. Species of 

 Helianthus, H. grosse-serratuSj H, laeti/lorus, H, mollis, 

 Heliopsis laevis and H. scabra, together with Cnicus arvensis 

 (rare) and C pumilus, Erigeron canadensis, Lactuca Scariola, 

 L. Scariola integrata and Silphium terebinthinaceum are the 



first to flower. They are followed by the Asters, A. novae- 

 angliae, A. oblongifolius, A. patens and A. sagittifolius , and 

 these in their turn by the goldenrods of which Solidago cana- 

 densis, S. nemoralis and S. petiolaris are the most common, 

 S, serotina being less common here and S. speciosa rare. 

 Aster sagittifolius is the last to flower during November, 



