Louisiana quillwort (Isoetes louisianensis)
Where Listed: WHEREVER FOUND
Isoetes louisianensis is a small, semi-aquatic, facultative evergreen plant with spirally-arranged leaves (sporophylls) arising from a globose, two-lobed corm. The pliant, hollow leaves are transversely septate and measure 2-3 mm (0.12 in.) wide and up to 40 cm (16.0 in.) long. Spore-containing structures (sporangia) are embedded in the pale, broadened bases of the leaves. Kral (1983) has suggested that aquatic quillwort leaves may vary in length depending upon water depth.
- States/US Territories in which the Louisiana quillwort, Wherever found is known to or is believed to occur: Alabama , Louisiana , Mississippi
- US Counties in which the Louisiana quillwort, Wherever found is known to or is believed to occur: View All
|Status||Date Listed||Lead Region||Where Listed|
|1992-10-28||Southeast Region (Region 4)||Wherever found|
» Federal Register Documents
|Date||Title||Plan Action Status||Plan Status|
|1996-09-30||Louisiana Quillwort||View Implementation Progress||Final|
|Date||Citation Page||Title||Document Type|
|1995-09-27||60 FR 49854 49855||Notice of Availability of a Draft Recovery Plan for the Louisiana Quillwort Fern for Review and Comment||
|2010-04-09||75 FR 18233 18234||5-Year Status Reviews of 10 Southeastern Species; Notice of initiation of reviews; request for information||
|2012-06-20||Louisiana quillwort (Isoetes louisianensis) 5-year Review: Summary and Evaluation|
» Critical Habitat
No critical habitat rules have been published for the Louisiana quillwort.
» Conservation Plans
No conservation plans have been created for Louisiana quillwort.
» Life History
Key morphological features that differentiate Isoetes taxa are megaspore ornamentation, texture, and size, and length of the velum (a membranous flap of tissue covering the sporangium). Megaspores are white and reticulate-cristate in texture with relatively thick proximal ridges; they measure 500 to 625 micrometers (approximately 0.02 in.) in diameter. Surface texture of the girdle (a narrow band along the distal side of the equatorial ridge encircling the megaspore) is obscure and not distinguishable from the overall texture of the spore. Microspores are light brown in mass and densely spinulose; they measure 25 to 35 micrometers (approximately 0.001 in.) in diameter. The velum in I. louisianensis covers less than one-half of the adaxial wall of the sporangium and the sporangial wall is brown-streaked. Biosystematic studies indicate that this species is a tetraploid (2n=44).
» Other Resources
NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.
ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.
FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.