. high macrophyte standing crops (Brenner et al. 1990). Many Florida 

 lakes have high nutrient concentrations because of edaphic reasons 

 or anthropogenic loading (Canfield and Hoyer 1988), and this also 

 stimulates macrophyte production. 



Macrophyte Growth Forms 



Macrophyte species are often grouped into growth-form 

 categories that describe whether or not the plants are rooted in 

 sediments and whether they grow laterally in the water or erect and 

 out of the water. Submerged macrophytes are those typically rooted 

 in sediments, growing completely under the water and usually 

 flexible due to a lack of rigid cellular tissue. Myriophyllum 

 heterophyllum Michx., Utricularia purpurea Walt, and Ceratophyllum 

 demersum L. are three examples of submerged taxa native to Florida, 

 while another common taxon, Hydrilla verticillata Royle is an 

 introduced exotic that has proliferated widely. Many submerged 

 ' taxa, when growing in dense stands, are regarded as nuisance species 

 that have a negative effect on lake recreational uses (Brenner et al. 

 1990). 



Floating-leaved plants can be divided into two categories 

 depending on whether they are rooted in sediments or not. Rooted 

 floating-leaved plants derive most of their nutrients from the 

 sediments (Carignan and Kalff 1980) and often have large peltate 

 leaves growing at the surface where they have access to sunlight and 

 atmospheric CO2 for photosynthesis. Common examples of these taxa 

 found in Florida are Nymphaea spp. (water-lily), Nelumbo lutea 

 (Willd.) Pers. (American lotus), Nuphar luteum (L.) Sibth. & Smith 



