Abstract: The anatomy structure traits suitable for long-distance hydrochory , of the seed of Myricaria laxiflora , an endemic riverain shrub , distributed along the Yangtze River from Chongqing to Yichang, were investigated . Results suggest that a mature seed, without endosperm, involves an erect embryo, and one layer of seed coat cells, outside of which is covered with a thick layer of lipid integument . The cells of hypocotyl and cotyledon array like longitudinal lines, and between the lines, an obvious linear gap can be seen. Sometimes, pits may appear in hypocotyl areas. In radicle areas, there are palisade cells and a lucuna which located above micropyle and formed via knockdown parenchyma cells . The central vascular strand goes through major part of embryo, and in the areas to where the central vascular strand can not extend, there exists a regional conducting system. The structural traits of seed facilitate species spreading but contrarily confine its efficacy. The results can provide biological foundations for ecological researches related to its population construction .

Key words: Myricaria laxiflora