villous waterclover

Marsilea villosa Kaulf.

Marsilea villosa, known as villous waterclover, is a fern species native to Oʻahu, Molokaʻi, and Niʻihau in Hawaii. It thrives in low elevation dry forests and shrublands, where it forms ephemeral pools during periodic flooding. The plant relies on standing water to open its sporocarps and release spores, allowing sperm to fertilize ova. New plants establish after the water recedes, and sporocarps form when the soil reaches a specific dryness. The leaves of M. villosa resemble a four-leaf clover, a characteristic shared with other members of the genus Marsilea.

Description

Marsilea villosa belongs to the family Marsileaceae and was first described in 1824 by Kaulf. It is adapted to seasonal wet and dry cycles, with its reproductive cycle dependent on these environmental conditions. The species is endemic to Hawaii and is an important part of its native ecosystems. Its common names include ʻihiʻihi in Hawaiian and villous waterclover in English.