Duckweed

• Duckweed is the smallest of the lake weeds.Jupiterimages/Photos.com/Getty Images
  
  Duckweed (Lemna spp.) is the smallest of all aquatic weeds, measuring just 5/32 inch in width. Watermeal is the smallest of the duckweed varieties, measuring just 1/32 inch wide. This flowering weed produces seeds and a single root that extends beneath the surface of the pond. This weed can be identified by the leaf-like part of the plant that is round and flat in shape.
  
  Small amounts of this weed in a lake are not problematic but this plant is able to reproduce quickly until it covers the entire surface of the water. Severe infestations of this plant are problematic because it reduces the level of oxygen in the water and prevents sunlight from reaching the water. (See Reference 1)
  
  

Alligatorweed

• Alligatorweed (Alternanthera philoxeroides Martius) is an aquatic weed that can be found growing in lakes and nearby land. This weed can be identified by its branched formation and two leaves. This is a flowering plant that produces white flowers with five sepals. The stem of this plant reproduces, causing the rapid spread of the plant.
  
  Unfortunately, large infestations of this weed can make lakes difficult for watercraft to navigate and be detrimental to the lake wildlife due to its absorption of valuable nutrients and oxygen. Once this weed has been identified, biological and chemical control methods can be used to control the infestation.
  
  

Curly-Leaf Pondweed

• Curly-leaf pondweed (Potamogeton crispus) is more commonly referred to as curly cabbage or crisp pondweed. This aquatic weed matures to a height of 2 to 3 inches and a width of 1/2 inch. The stem of this plant produces branches with alternate, toothed leaves. This weed grows rapidly throughout the spring and flowers in June.
  
  Some growth is beneficial because many fish and birds feed on the seeds and buds produced by the plant, but overgrowth can be problematic and require chemical or biological control methods.
  
  

Muskgrass

• Muskgrass (Chara spp.) is a lake weed or algae that is greenish-gray in color and which stays submerged below the waterline. This nonflowering plant is cylindrical in form and produces nodes which each have between six and 16 branches growing from them. Muskgrass acts as a home to invertebrates, which are then fed upon by lake fish. The muskgrass itself is also food for many types of ducks and aquatic birds. While some presence of muskgrass can be healthy for the lake's ecosystem, too much can be harmful and require mechanical or chemical control.