270 



The common watercross (Koripa nasturtium L.) was abundant in 

 (luarry B, having been carried in l)y tlie little stream from the north. Its 

 spread, however, was very slow, seemingly dependent on the amount of 

 surface soil carried in by tlie stream, since it did not thrive in the lime- 

 stone soil. 



A few plants of the button bush (Cephalanthus occidentalis L.) were 

 found around Ihe pond in ([uany ('. 



Fig. 4. 



A summary gives the following conclusions: ilj the lirst plants are 

 the algae in great variety and abundance. (2) A very few lichens. (3) A 

 few mosses. (4) Equisetum very rare; the soil not suited to its growth. 

 (5) Typical hydrophyte societies in the ponds, the Typha latifolia being 

 most conspicuoiis. The ponds slowly encroached upon by the sedges and 

 grasses: These plants form a soil for the many dicotyledons wliicli are 



