兵庫県三田市における絶滅危惧植物オクラコウホネ ( スイレン科) の分布, 生育環境と形態

抄録

Nuphar oguraense Miki (Nymphaeaceae) is endemic to southwestern Japan and one of the endangered water plant species .The habitat of this species in Sanda distric tis usually irrigation ponds. We surveyed 230 irrigatio nponds in Sanda City and found N. oguraense populations at 25 ponds. Other Nuphar species (AT .japonicum DC. and N. subintegerrimum (Casp. )Makino) were found in 19 ponds. N. oguraense was found to prefer oligotrophic ponds with low conductivity whose embankment is constructed by natural materials such as clay and rock.