| Family | Scientific Name | Common Name | Habitat | Distribution | Image |
|---|---|---|---|---|---|
| Isoetaceae | Isoetaceae | Quillwort Family, Merlin's-grass Family | |||
| Isoetaceae | Isoetes | Quillwort, Merlin's-grass |  (c) Cressler, Alan M. | ||
| Isoetaceae | Isoetes ×altonharvillii | ||||
| Isoetaceae | Isoetes ×brittonii | ||||
| Isoetaceae | Isoetes ×bruntonii | Virginia | |||
| Isoetaceae | Isoetes ×carltaylorii | ||||
| Isoetaceae | Isoetes ×dodgei | ||||
| Isoetaceae | Isoetes ×eatonii | ||||
| Isoetaceae | Isoetes ×fairbrothersii | ||||
| Isoetaceae | Isoetes ×robusta | ||||
| Isoetaceae | Isoetes appalachiana | Appalachian Quillwort | Seepages, small woodland streams, ephemeral wetlands, backwaters. | N. New Jersey and Pennsylvania south to ne. Florida, s. Alabama, and ne. Mississippi. See McAvoy (2021) for its occurrence in Delaware. |  (c) Spaulding, Dan - CC-BY-NC, permission granted to NCBG |
| Isoetaceae | Isoetes boomii | Boom's Quillwort | Shallow water of slow-moving streams. | Known from Georgia, Alabama, and Florida. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes butleri | Butler's Quillwort | Seepage areas on calcareous glades, sometimes also in seepage on non-calcareous rocks. | Kentucky, Illinois, Missouri and e. Kansas south to e. Texas and c. and nc. Texas; disjunct eastwards in sc. Kentucky, c. Tennessee, n. Georgia and n. and c. Alabama. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes chapmanii | Chapman’s Florida Quillwort | Springs, stream bottoms, river bottoms, ditches. | Florida Panhandle. | |
| Isoetaceae | Isoetes echinospora | Spiny-spore Quillwort | In acid lakes, ponds, and rivers (submerged to emersed), tidal mud flats. | Circumboreal, in North America from Greenland, Newfoundland and Labrador (Labrador), and Alaska south to Delaware, n. Ohio, Michigan, Wisconsin, Colorado, and California. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes engelmannii | Usually in permanent water bodies with active current. |  (c) Cressler, Alan M. | ||
| Isoetaceae | Isoetes flaccida | Winged Florida Quillwort | Springs, stream bottoms, strand swamps, river bottoms, ditches. | S. Georgia and se. Alabama south to s. Florida. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes georgiana | Georgia Quillwort | Streams. | Known only from Georgia (Colquitt, Dodge, Irwin, Tift, Turner, and Worth counties). |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes graniticola | Granite flatrocks. | Endemic to ec. Alabama and adjacent Georgia. |  (c) Cressler, Alan M. | |
| Isoetaceae | Isoetes hyemalis | Wintergreen Quillwort | Blackwater streams and sandy streambanks. | E. Virginia (Accomack County; McAvoy 2021) and sc. Virginia south through e. and c. North Carolina to Georgia, Alabama, and Florida Panhandle (Nelson 2000), in the Coastal Plain and lower Piedmont. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes junciformis | Rush Quillwort | Ephemeral wetland swales in bottomland hardwood swamps. | In sw. Georgia Coastal Plain (Tift and probably Calhoun counties, Georgia). |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes lacustris ssp. macrospora | Lake Quillwort | Submerged in lakes and permanent streams. | Apparently extirpated from the historic locality in Virginia. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes louisianensis | Louisiana Quillwort | Small streams, braided swamps, seepage areas. | S. Alabama, Mississippi, and Louisiana. Reported for Georgia by Duncan & Kartesz (1981); this species is extremely unlikely in Georgia and is treated as rejected for that state. |  (c) McFarland, Will - CC-BY |
| Isoetaceae | Isoetes mattaponica | Mattaponi River Quillwort | Tidal rivers. | Apparently endemic to freshwater tidal marshes along rivers flowing into the Chesapeake Bay (such as the Chickahominy, Pamunkey, and Mappaponi). |  © Lytton John Musselman |
| Isoetaceae | Isoetes melanopoda ssp. melanopoda | Blackfoot Quillwort | Floodplains. | S. Indiana, Illinois, and Missouri south to ne. Louisiana; probably represented eastward to c. Tennessee and s. Mississippi (the available material ambiguous) (Brunton & Britton 2006). |  (c) Soteropoulos, Diana - CC-BY-NC, permission granted to NCBG |
| Isoetaceae | Isoetes melanopoda ssp. silvatica | Eastern Blackfoot Quillwort | Clay soils in low woods, seeps on sandstone or granitic rocks, in NJ in clay-based depressions on Cape May. | Virginia south (in the Piedmont and Coastal Plain) to sw. Georgia, sc. Alabama, and s. Mississippi; disjunct in s. New Jersey. |  (c) Fleming, Gary P. |
| Isoetaceae | Isoetes melanospora | Black-spored Quillwort | In pools on granite flatrocks. | Endemic to Georgia. Material previously attributed here from Forty Acre Rock, South Carolina, is a new species. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes microvela | Banks of rivers in the outer Coastal Plain. | Endemic to e. North Carolina. |  © Richard LeBlond | |
| Isoetaceae | Isoetes mississippiensis | Mississippi Quillwort | Submersed in sluggish Coastal Plain streams. | Endemic to s. Mississippi. |  (c) Alford, Mac |
| Isoetaceae | Isoetes piedmontana | Piedmont Quillwort | In seepage on or near granitic flatrocks, rarely on sandstone (Altamaha Grit and Ridge and Valley). | Virginia south and west to ec. and n. Alabama; material in c. Texas has been placed here, but is likely to warrant description as a separate taxon (see Isoetes species 4). |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes riparia var. reticulata | Reticulate Shore Quillwort | Tidal areas. | District of Columbia to Virginia. | |
| Isoetaceae | Isoetes riparia var. riparia | Shore Quillwort | Shores. | Isoetes riparia is extirpated from most of its historic localities. | |
| Isoetaceae | Isoetes saccharata | Tidal waters, lakes. | Delaware to Virginia. | ||
| Isoetaceae | Isoetes septentrionalis | Northern Shore Quillwort | Freshwater ponds and shores. | Maine, Québec, and Ontario south to n. New Jersey and se. and c. Pennsylvania. |  (c) Lacroix-Carignan, Étienne - CC0 |
| Isoetaceae | Isoetes species 1 | Pools on granite flatrocks. | Forty Acre Rock, Lancaster County, South Carolina. |  (c) Julie, Tuttle - C, permission granted to NCBG | |
| Isoetaceae | Isoetes species 2 | Snow's Quillwort | On Altamaha grit sandstone. | Coastal Plain of Georgia. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes species 3 | Tidal marshes. | |||
| Isoetaceae | Isoetes tegetiformans | Merlin's-grass | In shallow pools on granite flatrocks. | Endemic to a few granite flatrocks in ec. Georgia (notably Heggies Rock), near the South Carolina line. |  (c) Cressler, Alan M. |
| Isoetaceae | Isoetes tennesseensis | Tennessee Quillwort | Rocky river shoals. | Endemic to Polk County, Tennessee, near the North Carolina-Georgia state line, in the Hiwassee River. | |
| Isoetaceae | Isoetes texana | Texas Quillwort, Tejas Quillwort | Alkaline ponds in wet prairie interdune swales. | Endemic to Coastal Plain of Texas (Aransas and Calhoun counties). | |
| Isoetaceae | Isoetes tuckermanii | Tuckerman's Quillwort | Shores, freshwater tidal marshes. | Nova Scotia south to n. New Jersey (reports of this species further south are apparently in error). |  (c) Steven, Daniel - C, permission granted to NCBG |
| Isoetaceae | Isoetes valida | Mountain Quillwort, Carolina Quillwort | Bogs (growing in Sphagnum), pools, ponds, and seeps. | C. Pennsylvania to s. Alabama. Reports from Mississippi are false, based on I. mississippiensis. Reported for Bell County, Kentucky (Krakowiak & Irick 2025). | (c) Cressler, Alan M. |
| Isoetaceae | Isoetes virginica | Virginia Quillwort | In woodland streams, intermittent streams, and diffuse streamhead wet forests. | Virginia to South Carolina. |  (c) Fleming, Gary P. |