Excerpts from Jim Conrad's
from the the July 21, 2008 Newsletter, after a visit to Land
Between The Lakes National Recreation Area in western Kentucky:
Farther offshore beyond the mats of algae the water's surface of the entire little inlet, a couple of acres large, was carpeted with pondweed, as shown above.
That's probably American Pondweed, POTAMOGETON NODOSUS, a native and coast-to-coast aquatic that, as in the picture, sometimes grows so thickly in shallow water that swimming or boating through it becomes difficult or impossible. For wildlife, however, it's wonderful stuff, providing basic structure for entire ecosystems in which fish, waterfowl and shorebirds are conspicuous. In the picture, the dark, slender items poking up from the water are fruiting spikes, each globular thing on the spike being a drupelike fruit containing a single seed. Below the carpet of leaves floating flatly on the water's surface each plant bears more slender submersed leaves.
Pondweeds are different enough from other flowering plants to be placed in their own family, the Pondweed Family, or Potamogetonaceae. Embracing about 80 species, the genus Potamogeton has the distinction of being the largest genus of truly aquatic seed plants of temperate regions. Weakley's Flora of the Carolinas lists about 21 species just for that area.