Abstract: Eleutherococcus senticosus , an important shrub under broad2leaved Korean pine and its seconday forests , has been declining since 1970’s , due to its effective therapeutic function in traditional Chinese medicine. So E. senticosus has been listed as vulnerable species in Plant Red Data Book of Chinese Rare and Endangered Plants (1992) . In this paper , the external and innate factors restricting the sustenace and expansion of E. senticosus populations were studied by field investigation , long-term observation and experimental ecology. Results showed that excessive excavation was the main external factor. The innate factors included high proportion of fruitless plants , few seed production , poor seed quality , weak disperse power , the phonomena of innate dormant seed and autotoxicity. Therefore , the vegetative reproduction has become the main approach for the sustenane of existing populations. But vegetative reproduction may result in decline of genetic diversity , thus cause the decrease in its resistance to variable environments. Under the co-action of the above factors , Eleutherococcus senticosus populations may reduce further , and their endangerment degree may increase.

Key words: aquatic higher plants, threatened species, classified standard, inland waters, sea area