(1) The results showed that RHDV was the pantropic virus injuring most tissues and cells, but the main injured organ was liver, the principal target cells were hepatocytes and endothelial cells.

(2) The pantropic type is 22.9%, the north temperate type 17.4% and the East Asia one 17.0% at generic level. The temperate elements are slightly more than the tropical ones(237:230).

(3) The river's flora can be divided into 15 distribution types and 14 subtypes. Among them, Pantropic, North temperate, Old world temperate and E. asia are important types.

(4) Analysis of genera flora indicates the temperate component (50.0%) is slightly more than tropics component (45.5%), and the Pantropic component is the most.

(5) The areal-types of the dominant families was cosmopolitan distribution and pantropic distribution totalling 48 families, accounting for 85.2%.