268 



shoots have grown up six decimeters. Whether these logs will with- 

 stand the winter storms and, together with some wreckage near by, 

 originate another ridge remains to be seen. 



Another case of accidental vegetation on the lower beach is very 

 temporary in duration and extent. It occurs south of Kenosha, where 

 Lake Michigan is cutting into the prairie. Some prairie plants, nota- 

 bly loosestrife {Lythniiii alatuiii), are carried bodily from the prairie 

 and are occasionally left stranded with their root systems in the damp 

 sand of the lower beach. They remain living until washed away al- 

 together by a succeeding storm. 



The part of the lower beach which is devoid of plants comes next 

 into consideration. The area is bare because plants can not obtain a 

 footing there — and not because they will not grow there. The rea- 

 sons which are given briefly by Cowles (1899:114) and more fully 

 by Jennings (1909:310) are as follows: the alternate washing by 

 storm waves and the severe drying out under the sun, combined with 

 the washing about of the sand when submerged and its blowing 

 about when dry, prevent the establishment of any plants whose seeds 

 actually do germinate. After a rainy spell of two or three days' du- 

 ration, such as August 13-15, 1909, it is not at all a difficult task to 

 find, scattered over the slightly damp sand, seeds which have begun 

 to germinate. With the reappearance of the sun and the drying of 

 the surface sand, these partially germinated seeds dry up and are 

 blown about by the wind. That living forms, however, can maintain 

 themselves on this area is clearly shown by the industry of the turn- 

 stone {Arenaria iiifcrprcs), which, during its brief sojourn in this 

 region in the spring and fall migrations, is continually occupied in 

 ferreting out the small insects and other animals wiiich are found 

 under the pebbles. 



The junction of this area with the portion of the beach continually 

 washed jjy the waves is the location of the willow log and wreckage 

 previously mentioned. One piece of wreckage, a little over a meter 

 in length, projects somewhat over a decimeter into the air. The 

 ordinary waves just fall short of its lakeward side. On the landward 

 side, stretching southwestward, is a miniature dune of sand in which 

 are growing the following plants: Juiupcnis horizontalls — a single 

 healthy shoot, 3 cm. in length, growing next to the wreckage; Pni- 

 nns puinila (sand cherry) — a sprawling shrub; Poa coinprcssa (Eng- 

 lish blue-grass) — a few plants; Potcntilla anserina — one plant with 

 five radiating runners ; Bqnisctum arvcnse — a few plants ; a com- 

 posite which was so depauperate as to be unrecognizable; and a con- 

 volvulaceous plant, together with the exposed roots of Cdamovilfa 

 longifolia. A wagon track through the dune explains the planting of 



