Isoetes louisianensis Thieret

Louisiana Quillwort

Herb

Perennial

Vascular

Louisiana Quillwort is a native seedless vascular plant in the Quillwort family (Isoetaceae). It is native to Alabama, Mississippi, and Louisiana. It Alabama it is known to occur in two counties in southwest Alabama. It grows in shallow water and low muddy areas near streams. Louisiana Quillwort is a perennial from a corm (a fleshy underground stem). The corm is globose in outline and two-lobed. Roots are produced from the base of the corm and leaves (microphylls) from the upper portion. The leaves are spirally arranged, hollow, and transversely septate. The leaves are linear and taper gradually to a pointed tip. Leaves are glabrous and bright green in color. Some leaves contain sporangia at their base. These leaves are known as sporophylls. The sporangium is covered by a flap of tissue called a velum. The velum covers less than half of the sporangium. Louisiana Quillwort is heterosporous—producing two kinds of spores. Megaspores are larger and white in color. The surface of the megaspore is cristate with thick ridges. Smaller spores known as microspores are brown in color with a spinulose surface. Louisiana Quillwort was listed as an Endangered Species by the US Fish and Wildlife Service on October 28, 1992. In Alabama, it is listed as a S1 species (typically 5 or fewer occurrences, very few remaining individuals, acres, or miles of stream, or some factor of its biology making it especially vulnerable in the state), and globally it is listed as a G2 species (imperiled globally because of rarity (6 - 20 occurrences, or few remaining acres, or miles of stream) or very vulnerable to extinction throughout its range because of other factors).--A. Diamond

Listed as <a href="https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=S00T">Federally Endangered</a> as of 28 Oct 1992.</a>

Native Endangered-US S1 (State Rank) G2 (Global Rank)

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