f^ 



1902] THE ECOLOGY OF THE DELAWARE COAST 295 



[c] Swamps and meadows. — The swamps found between the 

 two series of dunes are undrained for at least part of the year, 

 the history of Silver lake being a good example of what prob- 

 ably takes place in the majority of lakes and swamps of this 

 region. During winter storms the sea comes in through open- 

 ings in the outer ridge and floods the lake until its boundaries 

 extend around the low dunes in its vicinity. During the summer 

 months the lake margin retreats, leaving wet soil, and sometimes 

 water standing in the depressions. This drying process nearly 

 converts Silver lake itself into a swamp, very little open water 

 being visible, an increase only occurring at times of unusually 

 high storm tides and during showers. The first event occurs 

 but rarely, and the amount contributed by the second method is 

 not sufficient to supply the loss occasioned by evaporation 

 during the hot dry days. 



Around the edge of Silver lake grows Scirpus americanus {S, 

 p2i?fge?is), the growth being much more luxuriant at the north 

 end, where the water is fresh. In places also occur Cyperus 

 ferox, C, diandrus elongatiis, and ^. Nuttallii. At the south end of . 

 the lake, where the main entrance from the sea lies, were found 

 such strand forms as Polygonum maritbmimy Do?idia americana 

 [Suaeda li?iearis), and Atriplex hastata {^A. patuliim hastatuni) ; 

 while at the northern end the formations show a tendency toward 

 fresh-water forms, passing from a swamp to a wet meadow and 



+ 



thence to drier conditions. Here we find such forms as Scirpus 

 amertca?iuSy Hydrocotyle umhellata , Hypericum canadense, Cassia 

 nictita?is, Pluchea catnphorata, Li?ium virginianum, Li?iaria ca7ia- 

 densisj Ftiirena sqiiarrosa, Xyris flextiosa, becoming gradually 

 replaced by Spa7'iina patens [S, ju?icea) , Ambrosia artemisiaejolia, 

 Solidago sempervirens, Erechtites hicracifolia, Giiaphalium purpureum, 

 Erigero7i ramosus (^. strigosus), Carex silicea (^. strannnea monil- 

 tformis), Junais te?i2iis, Fimbristylis castanea, and Scirpus subtermi- 

 7ialis terrestris. Xauthiiim sp., Molhigo verticillata, and other more 

 xerophytic forms appear on low elevations and toward the dunes. 

 West of the lake lies a small meadow worthy of mention 

 because it holds a plant assemblage not seen elsewhere, although 



