Distribution Status and Causation of Endangerment of Isoetes sinesis Palmer in Zhejiang Province

Isoetes sinensis Palmer (Isoetaceae) is an endangered swampy perennial.Seven wild populations were recorded in Zhejiang Province, but only two sub-populations were found in Songyang County,Zhejiang Province in this investigation.Habitat destruction and water pollution were considered two main causation of local extinction of this species.The total area of this two sub-populations were less than 1000 m² and they were in endangered status.Their communities would be substituted by land communities in the process of vegetation succession.Some measures of conservation for this two sub-populations that should be taken were suggested.