STUDIES ON AQUATIC VASCULAR PLANTS IN HUAMA LAKE IN EAST HUBEI——Ⅱ. THE AQUATIC VEGETATION

The Huama Lake is one of the Hubei Jianghan-Lakes. It covers an area of about 27.5km². There are abundant aquatic vascular plants in the lake, and 20 species of them are dominant. According to our investigation on the lake and the dominance, the degree of gathering, biomass, life form, layer and habitat of aquatic vascular plants, we cut aquatic vegetation types as follows: 1)Carex spp. Ass.2)Polygonum lapathifolium+Alternanthe a philoxeroides Ass.3)Zizania caduoiflora Ass.4)Spirodela polyrhiza Ass.5)Nelumbo nucifera Ass.6)Euvyale ferox-Vallisneria spivalis+Myriophyllum vertioiuatum Ass.7)Nymphoides peltatum Ass.8)Nymphoides indica Ass.9)Trapa spp. Ass.10)Trapa spp. Potamogeton orispus+Vallisneria spiralis+Najas spp. Ass.11)Najas spp. Ass.12)Vallisnevia spiralis Ass.13)Ottelia alismoides Ass.14)Potamogeton malaianus Ass.15)Ceratophyllum demersum+Myriophyllum verticillatum+Potamogeton crispus+Vallisneria spiralis Ass.The dominant plant associations are Trapa spp. Ass., Ceratophyllum demersum+Myriophyllum verticillatum+Potamogeton crispus+Vallisn eria spiralis Ass. and Potamogeton malaianus Ass. These associations are composed of 82 species and 2 varieties of aquatic vascular plants.The distribution of aquatic vegetations in the lake exhibits irregular zonations and can be classified into four vegetation zones from the edge to the centre of the lake: hygrophyte vegetation, emergent vegetation, submorsed vegetation and floating attaehed vegetation.