Sunday, December 15, 2019

The Mosquito Fern

There is something to be said for going to the same place more than once and with different people. Recently I went to the Newman Wetlands Center in Hampton, GA for the annual holiday party for the Georgia Botanical Society. We have used that location for several years now and I wondered if I’d learn anything new by going there. Of course the fellowship of fellow native plant enthusiasts is always worth the trip, so I went.

After a wonderful potluck lunch and brief meeting, the group headed out into a beautiful day for a walk along the boardwalks. Birds were singing and we found plenty of plants to talk about, including a long and lively discussion about cherrybark oak (Quercus pagoda). Those of us who had been there before had plenty to share with new folks, including this uncommon species of oak whose leaves were scattered over a wide area.

As we passed over a stretch of water, clumps of a tiny, burgundy-tinted aquatic plant were very evident. While the bright green parrot feather (non-native) was very noticeable, this new-to-me plant needed to be present in abundance to be appreciated. And present in abundance is exactly how it gets its name: mosquito fern (Azolla cristata).

According to my research, when it is widespread, it is so thick as to deter the development of mosquitoes in what is otherwise still or slow moving water. It is described as a small aquatic nitrogen-fixing fern. In addition, it is described as an annual! What a unique plant.

Mosquito fern (Azolla sp.) covering several feet

While we assumed the species we found is native, the Georgia fern book indicates that we would need a microscope to be sure: “The minute male spores of Azolla species join to form jellylike masses with protruding arrow-like hairs, called glochidia. Species identification is based on details of the glochidia and requires a microscope for examination. As fertile plants are rarely found, species identification is usually difficult.”

What a fun find and it's always time well spent when you're with plant folks!

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