 |
| Plate 49.--Classification: SYSTEM Lacustrine, SUBSYSTEM Littoral, CLASS Emergent Wetland, SUBCLASS Nonpersistent, DOMINANCE TYPE Juncus militaris, WATER REGIME Semipermanently Flooded, WATER CHEMISTRY Fresh-Circumneutral, SOIL Mineral. Subordinate plants include common threesquare (Scirpus americanus) and pickerelweed (Pontederia cordata). During the spring, emergent vegetation is not evident at this site, and waves break on the gravel shore visible in the foreground. (Washington County, Rhode Island; July 1977; Photo by F. C. Golet) |
 |
| Plate 50.--Classification: SYSTEM Palustrine, CLASS Unconsolidated Bottom, SUBCLASS Sand, WATER REGIME Intermittently Exposed, WATER CHEMISTRY Fresh-Alkaline. Rushes (Juncus spp.), spike rush (Eleocharis sp.), and smartweed (Polygonum sp.) grow in shallow water along the shore of this 0.4-ha (l-acre) pond which occupies a depression amidst sand dunes on the southern shore of Lake Michigan. (Indiana Dunes National Lakeshore, Porter County, Indiana; May 1985; Photo by F. C. Golet) |
 |
| Plate 51.--Classification: SYSTEM Palustrine, CLASS Unconsolidated Bottom, SUBCLASS Mud, WATER REGIME Permanently Flooded, WATER CHEMISTRY Fresh-Circumneutral, SPECIAL MODIFIER Impounded. This beaver pond is situated in the San Juan Mountains. (Gunnison County, Colorado; Photo by R. M. Hopper) |
 |
| Plate 52.--Classification: SYSTEM Palustrine, CLASS Unconsolidsted Bottom, SUBCLASS Mud, WATER REGIME Semipermanently Flooded, WATER CHEMISTRY Mesosaline, SOIL Mineral. This photo was taken during drouth conditions; the bottom is being invaded by pioneer species including summer cypress (Kochia scoparia), golden dock (Rumex maritimus), and goosefoot (Chenopodium glaucum). (Stutsman County, North Dakota; August 1961; Photo by R. E. Stewart) |