Hakone Stonewort (Chara globularis var. hakonensis)
The Hakone Stonewort was described in 1965, originally as a full species, this freshwater alga was endemic to Lake Ashi, also known as Ashi-no-ko, a crater lake in the Hakone area of the Kanagawa Prefecture on the island of Honshu, Japan.
This alga apparently disappeared due to water pollution which lead to a decrease of sunlight, which again lead to the dieback of the algae meadows.
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The species was apparently locally known as Hakone-syazikumo.
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edited: 14.09.2019