Isoetes, commonly known as the quillworts, is a genus of lycopod. It is the only living genus in the family Isoetaceae and order Isoetales. There are currently 192 recognized species, with a cosmopolitan distribution mostly in aquatic habitats but with the individual species often scarce to rare. Species virtually identical to modern quillworts have existed since the Jurassic epoch, though the timing of the origin of modern Isoetes is subject to considerable uncertainty.
Isoetes louisianensis, the Louisiana quillwort, is a small, grass-like aquatic plant of the family Isoetaceae. It is "one of the rarest quillworts in North America." It occurs in only five locations in St. Tammany and Washington Parishes of Louisiana, as well as some spots in southern Mississippi and south-central Alabama. It is federally listed as an endangered species, partly due to its highly restricted range.
Jordan Pond is an oligotrophic tarn in Acadia National Park near the town of Bar Harbor, Maine. The pond covers 187 acres (76 ha) to a maximum depth of 150 feet (46 m) with a shoreline of 3.6 miles (5.8 km).
Lobelia dortmanna, Dortmann's cardinalflower or water lobelia, is a species of flowering plant in the bellflower family Campanulaceae. This stoloniferous herbaceous perennial aquatic plant with basal leaf-rosettes and flower stalks grows to 0.7–2 m (2.3–6.6 ft) tall. The flowers are 1–2 cm long, with a five-lobed white to pale pink or pale blue corolla, produced in groups of one to ten on an erect raceme held above the water surface. The fruit is a capsule 5–10 mm long and 3–5 mm wide, containing numerous small seeds.
Isoetes taiwanensis is a species of plant in the family Isoetaceae. It is endemic to Taiwan, and the only species of quillwort there. Isoetes taiwanensis can now only be found in Menghuan Pond in Yangmingshan National Park.
Isoetes engelmannii is a species of aquatic plant in the family Isoetaceae. It is referred to by the common names Engelmann's quillwort or Appalachian quillwort, and is the most widely distributed species of its genus in eastern North America. Its range extends from Ontario in the north, south to Florida and west Arkansas and Missouri. It can be found from April to October in temporary pools, bogs, marshes, stream edges, swamps and along wet roadsides.
Isoetes appalachiana, commonly known as the Appalachian quillwort, is an aquatic pteridophyte that is widely distributed in the eastern United States. It is most frequently encountered in wetlands at low to middle elevations of the Appalachian Mountains in Pennsylvania, though its range extends from there south to Florida and Alabama along the eastern slopes of the mountains. It is a tetraploid and is grouped in the Isoetes engelmannii complex.
Isoetes valida, commonly known as the strong quillwort or true quillwort, is an aquatic lycophyte native to eastern North America. It is found primarily in the Appalachian Mountains from Pennsylvania south to Alabama and Georgia. In addition, one collection of the plant was made in a railway ditch in Wilmington, Delaware in the 1860s, but this was most likely an accidental introduction.
Isoetes tegetiformans, commonly known as mat-forming quillwort or mat-forming Merlin's grass, is an aquatic lycophyte endemic to the U.S. state of Georgia. It grows exclusively in shallow, temporary pools on granite outcrops, often with only 2 cm of soil. Only 7 populations are known to exist, and three of these have been destroyed since the plant's discovery in 1976. The remaining populations are threatened with habitat destruction due to quarrying, though the species is protected under the U.S. Endangered Species Act. New leaves quickly sprout after fall and winter rains, but during the dry summer months these typically shrivel.
Isoetes melanospora, commonly known as black-spored quillwort or black-spored Merlin's grass, is a rare and endangered aquatic lycophyte endemic to the U.S. states of Georgia and South Carolina.
Isoetes eludens is an aquatic plant in the genus commonly known as quillwort that is native to the Kamiesberg Mountains in Namaqualand, South Africa. So far it is known to grow only in a single !gau (gnamma), a small temporary pool formed in a hollowed out area of granite rock. It has likely been growing in that region for millions of years, but was only discovered in 2007 and described in 2009. The specific epithet eludens refers to the fact that it eluded discovery, in spite of several searches in recent years in the area for new quillwort species.
Isoetes caroliniana, common name Carolina quillwort, is a wetlands plant native to the mountains of Tennessee, North Carolina, Virginia and West Virginia. It is an emergent plant found in lakes and bogs. It is closely related to I. georgiana but can be distinguished by its unpigmented sporangium wall.
Isoetes echinospora, also known as spiny quillwort, spiny-spored quillwort or spring quillwort is a species of quillwort in the Isoetaceae family, and is the most abundant species in Canada. It can be found in shallow aquatic environments from Labrador and Newfoundland to Alaska, and south to Pennsylvania, Wisconsin, Michigan, Colorado, and California. In Germany it is found in only two locations: the Feldsee and Lake Titisee, both in the High Black Forest.
Isoetes acadiensis, the Acadian quillwort is a species of quillwort in the Isoetaceae family described by Kott in 1981. It can be found along the shores of lakes, ponds, and rivers in Newfoundland, Nova Scotia, and New Brunswick, as well as in the American states Maine, Massachusetts, and New Hampshire. It has a similar distribution to that of I. tuckermanii. It bears 9 to 35 mostly recurved leaves, each 5–21 cm long. The leaves are usually dark green, though can occasionally be tinged with red. The sporangium can be up to five millimeters long and 3 millimeters in length, covered one sixth to one third by the velum. The spherical megaspores are 400-570 micrometers in diameter, and bear smooth ridges. The kidney shaped microspores are 25 to 30 micrometers long. It was originally believed to be a member of Isoetes hieroglyphica because of their similar megaspore structure.
Isoetes occidentalis, the western quillwort, is a species of quillwort in the family Isoetaceae. It can be found in aquatic habitats of coastal Alaska and British Columbia south to California and Colorado. It is frequently found on Vancouver Island and around the Fraser Valley region. It bears 10 to 30 or more rigid, dark green leaves, each 5 to 20 centimeters long. The velum covers one fourth to one third of the orbicular sporangium, which is 5 to 6 millimeters in diameter. The ligule is shaped like a shortened triangle. The white megaspores are 500 to 700 micrometers in diameter and bear sharp ridges and crests. The microspores are 36 to 43 micrometers long. Though the leaves seem to bear resemblance to those of I. lacustris, especially the occasionally occurring reddish base, I. occidentalis is a hexaploid and I. lacustris is a decaploid.
Isoetes beestonii is a species of isoetalan plant from the latest Permian of New South Wales and Queensland. Originally considered earliest Triassic, it is now known to be latest Permian in age, immediately before the Permian Triassic mass extinction. It has been suggested to be the earliest member of the genus Isoetes, which contains living quillworts, though it differs from living Isoetes in some aspects, with modern forms of Isoetes possibly emerging during the Jurassic.
Tomiostrobus is an extinct quillwort genus from the Early Triassic of Australia, China and Russia, which was especially widespread in the aftermath of Permian Triassic mass extinctions.
Yulen is a nature reserve in Pirin National Park, located in the homonymous mountain range in south-western Bulgaria. It is situated in Bansko Municipality, Blagoevgrad Province. Yulen was declared on 26 August 1994 to monitor the growth of alpine plant species without human influence, as well as to protect rare plant and animal species. It spans a territory of 3156 ha or 31.56 km2.
Isoetes melanopoda is a species of nonflowering vascular plant belonging to the quillworts in the family Isoetaceae. Its common names include: black-footed quillwort, midland quillwort, and prairie quillwort.
