AbstractRanalisma rostratum (Alismataceae) is an endangered aquatic plant , and now there exists only one population in China. In its natural habitat , Huli marsh in Chaling , Hunan Province , the best growing plants were observed at microsites where the water depth is five to 10 cm , and the plants grow in emergent form. R. rostratum reproduces asexually or sexually , and recruitment of asexual propagules into population is a very importment way to maintain the natural population size. Although seed production does not appear to limit R. rostratum , restricted dispersal of propagules and seeds , low seed viability , low germinability , slow growth of seedlings under all conditions , and habitat loss due to agriculture appear to be more important reasons for the endangerment of this plant .