974 



MINNESOTA BOTANICAL STUDIES. 



ment and indicate a former higher level of the lake. Back 

 strand may be defined as elevated beach formation rising at the 

 rear of the mid- strand. It is always characterized by a much 

 higher per cent, of humus in the soil, consequently by soil of a 

 darker color, although in many cases the difference is slight. 

 Yet even back strand composed apparently of pure sand will 

 upon comparison with the mid- strand or front strand appear dis- 

 tinctly darker in color. Consequently it becomes the abode of 

 those plants which have more of a thermophytic or nitrophytic 

 character. Yet if the sand be still the principal constituent of 

 the soil as is ordinarily the case a peculiar grouping of plants, 

 sometimes reminding one directly of the sand dune formations, 

 arises. A list of plants of the back strand is here appended, 

 taken from observations on Oak point. 



Back strand Group at Oak Point. 



Dryopteris spinulosa. 

 Equisetum arvense. 

 Juniperus communis. 

 Picea mariana. 

 Pinus divaricata. 



strobus. 



resinosa. • 



Taxus minor. 

 Agrostis alba. 

 Alopecurus geniculatus. 

 Calamagrostis canadensis. 

 Polygonatuni commutatum. 

 Smilax herbacea. 

 Vagnera stellata. 

 Populus balsami fera. 

 Populus deltoidea. 

 Populus tremuloides . 

 Comandra umbellata. 

 Polygonum erectum. 

 Silene antirhina. 

 Ranunculus pennsylvanicus. 

 Arabis brachycarpa. 



Cerasus virgiuiana. 

 Rosa woodsii. 

 Rubus strigosus. 

 Rhus glabra. 

 Rhus radicans. 

 Celastrus scandens. 

 Parthenocissus quinquefolia. 

 Vitis vulpiua. 

 Cornus baUeyi. 

 Arctostapbylos uva-ursi. 

 Fraxinus americana. 

 Apocynum cannabinum. 

 .Lycopus sinuatus, 

 3Ientha canadensis. 

 Scutellaria galericlata. 



lateriflora. 



Stachys palustris. 

 Galium trifidum. 

 Campanula rotundifolia. 

 Erigeron ramosus. 

 Hieracium scabrum. 

 Solidago juncea. 



Another example of back strand, quite clearly distinguished 

 from the country behind it, was examined at Sandy beach, and 

 the list of its dominant plants is appended. 



