Isoetes

plant genus

Also known as: Isoëtes

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Last updated

July 22, 2026

Quick Summary

Isoetes, also known as quillworts, are a genus of about 250 species of seedless vascular plants belonging to the order Isoetales. These plants are typically aquatic or semi-aquatic, found in cooler regions of North America and Eurasia.1

Quillworts are characterized by their grassy, spikelike leaves that grow from a corm-like base. Each leaf base contains a large sporangium, where spores are produced. Many quillwort species are endangered due to habitat loss and pollution.1

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lycophyte
Annotated classification
…many years the species of Isoetes were difficult to distinguish, but, since the discovery that frequent hybridization was obscuring the differences between species, they are more clearly understood; Isoetes includes about 250 species in swampy, cooler parts of the world. †Order Pleuromeiales Extinct unbranched plants, with subterranean, rootlike rhizophores; heterosporous;…
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…many years the species of Isoetes were difficult to distinguish, but, since the discovery that frequent hybridization was obscuring the differences between species, they are more clearly understood; Isoetes includes about 250 species in swampy, cooler parts of the world. †Order Pleuromeiales Extinct unbranched plants, with subterranean, rootlike rhizophores; heterosporous;…
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