Two populations of Pistia stratiotes L. in an unused aquaculture pond and a roadside drainage ditch were sampled monthly for 1.5 years to examine seasonal trends in leaf area, leaf and plant densities, leaf and root biomasses, and flowering. Biomasses and leaf areas were sharply depressed by winter cold, especially by subfreezing temperatures. Spring regrowth occurred by budding and the proliferation of small plants. From late spring through mid-summer, leaf size and plant biomass increased and plant density decreased; these variables did not change markedly between August and December. In both populations, flowering occurred synchronously during December, but no sexual reproduction was observed. Winter cold is a major determinant of growth patterns in south Florida, but local conditions are also important.
Measurements from the day of unfurling until subsidence into the water showed that leaves reached an average length of 15.3 cm after 2 weeks and declined towards the water at a rate of 2.9° day−1.
Two populations of Pistia stratiotes L. in an unused aquaculture pond and a roadside drainage ditch were sampled monthly for 1.5 years to examine seasonal trends in leaf area, leaf and plant densities, leaf and root biomasses, and flowering. Biomasses and leaf areas were sharply depressed by winter cold, especially by subfreezing temperatures. Spring regrowth occurred by budding and the proliferation of small plants. From late spring through mid-summer, leaf size and plant biomass increased and plant density decreased; these variables did not change markedly between August and December. In both populations, flowering occurred synchronously during December, but no sexual reproduction was observed. Winter cold is a major determinant of growth patterns in south Florida, but local conditions are also important.
Measurements from the day of unfurling until subsidence into the water showed that leaves reached an average length of 15.3 cm after 2 weeks and declined towards the water at a rate of 2.9° day−1.
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