Wolffiella floridana in Western Pennsylvania

The large number of reservoirs, artificial lakes, and farm ponds created in recent years has increased tremendously the number of situations open to invasion by aquatic plant species. Many hydrophytes are widely dispersed and local irregularities in distribution may simply reflect the presence or absence of bodies of water within the area. Other species are not so wide-spread and their restricted distribution is not easily explained. It is, to be expected, however, that many aquatic plants now showing discontinuous distributions will gradually extend their present ranges into newly-created bodies of water.