Isoetes echinospora Durieu (= Isoetes tenella Léman )
spiny-spored quillwort

Family: Isoetaceae
plant plant leaf base with sporangium Megaspores

The genus Isoetes is easy to recognize, but the distinctions between species are more challenging. Fortunately we have only two species in Wisconsin, of the 24 species reported for North America. The most reliable means of identifying the species of Isoetes requires observation of the megaspores with a microscope. Megaspores of I. echinospora are covered with numerous spines, and are easily distinguished from the curving ridges of I. lacustris megaspores.

I. echinospora grows on lake beds, usually completely submersed in the water and often overlooked. The water must be reasonably clear to allow Isoetes to grow on the lake bed and most known locations are of oligotrophic lakes (i.e. of low productivity) with slightly acid water. If there is activity in the near shore area, such as boat launches, or swimming beaches there will usually be plants of Isoetes uprooted by the activity and washed up on shore. It ranges from Alaska across northern Canada to Newfoundland, south to California, Idaho and Montana in the west and northern Minnesota to Michigan and New Jersey in the east. In Wisconsin it appears limited to the northern counties.

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