Plectospira Myriandra, A Rediscovered Water Mold in Japanese Soil

One isolate of water mold from field soil in Shikoku Island, Japan, was Plectospira myriandra, rediscovered 59 years after its original description by Drechsler in 1927. During a survey of pythiaceous fungi in Japanese soils, an interesting fungus was isolated from a field in which bamboo had been grown in Nangoku City of Shikoku District (Island), Japan. This fungus was very similar to Aphanomcyes, but unlike Aphanomyces, it featured lobulate sporangia with uniseriate production of zoospores inside long evacuation tubes. Also, there were numerous antheridial elements per oogonium, and oospores and parthenospores borne in oogonia with and without antheridia, respectively. The morphology and taxonomy of the fungus identified as Plectospira myriandra Drechsler is described in this report. A preliminary report has been published (Watanabe, 1986).