Morphological characteristics and biomass allocation were examined for two species ofTyphain a small pond.Typha latifoliadiffered fromT. angustifoliain having shorter leaf height, wider leaves, greater leaf surface area, greater allocation to leaves, greater number of smaller rhizomes, greater allocation to vegetative reproduction, smaller allocation to sexual reproduction, and fewer number of flowering plants. For both species, those plants growing in deeper water had taller leaves, a greater allocation to leaves, and a decreased allocation to sexual and vegetative reproduction. Previous studies of these populations have demonstrated that these two species are segregated according to water depth withT. latifoliabeing competitively superior in shallow water (less than 15 cm) butT. angustifoliahaving the potential to grow in deeper water thanT. latifolia. Results from this study indicate thatT. latifoliais competitively superior in shallow water because of its greater leaf surface area but thatT. angustifolia's tall, narrow leaves and large rhizome storage permit it to grow in deeper water thanT. latifolia. The greater amount of sexual reproduction inT. angustifoliais correlated with its more restricted distribution and fugitive nature.