ON AQUATIC VEGETATION OF THE LAKE JINGPO

Jinpo lake is located in Ning An County of Heilongjiang Province( 44°N, 129°E) at an elevation of 350 metres. It covers an area of about 300 km2. The maximum water depth of the lake is about 60 m., the transparency ranges 1.7—2.5 m., and ph ranges 6—6.5. Annually, the mean highest water temperature is about 23℃ in July-August, while the lowest, about 1.5℃ in Junuary. This lake is rich in aquatic plantts, which are mainly distributed in the southern and western parts of the lake. Based on a field observation on the life-form and the domination of the species 3 types and 12 communities are determined as follows:1. Erect types :(1) Artemisia selengensis Community.(2) Phragmites communis Community.(3) Zizania caduciflora Community.(4) Alisma orientalie + Sagittaria trifolia Community.(5) Eleocharis kamtschatica Community.(6) Calamagrostis epigejos + Miscanths sacchariflorus Community.(7) Carex humida + Carex rhynchophysa Community.2. Leaf-floating types :(1) Polygonum amphibium Community.(2) Trapa manshurica Community.(3) Nymphoids peltatum Community.3. Submerged types :(1) Potamogeton malaianus + P. tepperi Community.(2) Hippuris vulgaris Community.The changeable water depth in the lake is thought to have a. great influence upon the sccession of community, about which a discussion is given in the present paper.