A PHYTOCOENOLOGICAL STUDY ON THE EMERGENT VEGETATION IN FUTOU LAKE Ⅱ. THE STRUCTURE OF COM. NELUMBO NUCIFERA

The structure of Com. Nelumbo nucifera was analysed in detail. The community was a polydominant one, characterised by its rich flora and growth-form, and had well developed emergent, leaves-floating and submersed vegetation strata. The dominant species showed obvious alternation, especially Potamogeton crispus, Hydrilla verticillata and Ceratophyllum demersum in the submersed stratum. We think the main reason for this phenomenon is their different autecological characters. The distributions of different populations showed zonation. In addition, the leaves, flowers and fruits of N. nucifera showed patterns which could be attributed to the branching features of its rhizom system. The vertical structure was also described, three vegetation strata(emergent, leaves-floating, submersed) could be distinguished in most area of the community. Owing to the growth pattern of the parvopotamids and the water level, a microstratification was developed in the submersed stratum.