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. Some botanists split the genus, separating two South American species into the genus Stylites, although molecular data place these species among other species of Isoetes, so that Stylites does not warrant taxonomic recognition. 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 lacustris, the lake quillwort or Merlin's grass, is a boreal quillwort native on both sides of the northern Atlantic Ocean. Synonyms include Isoetes hieroglyphica.
Isoetaceae is a family including living quillworts (Isoetes) and comparable extinct herbaceous lycopsids (Tomiostrobus).
Alsophila jimeneziana, synonym Cyathea crassa, is a species of tree fern endemic to the Dominican Republic. Little is known about this rare tree fern.
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 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.
Parablechnum ambiguum, synonym Blechnum ambiguum, is a species of fern in the family Blechnaceae. growing on wet rocks in eastern Australia, often seen near waterfalls. It is common around Sydney.
Crepidomanes intricatum, synonym Trichomanes intricatum, is known as the weft fern. The genus Crepidomanes is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not by some other sources. As of October 2019, Plants of the World Online sank the genus into a broadly defined Trichomanes, treating this species as Trichomanes intricatum.
Stegnogramma pilosa, synonym Thelypteris pilosa, is a fern species in the family Thelypteridaceae. It is closely related to Stegnogramma burksiorum ; the two have been treated as a species complex. Stegnogramma pilosa is native to Mexico, Guatemala and Honduras.
Parablechnum minus, synonym Blechnum minus, is a small fern growing in moist situations in a variety of habitats in eastern Australia. It is often seen by streams.
Doodia maxima, also known as the giant rasp fern, occurs in moist open forests in eastern Australia. It was considered to be a natural hybrid. Some sources place the species in the genus Blechnum, others, including the Pteridophyte Phylogeny Group classification of 2016, place it in Doodia.
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.
Lomaridium contiguum, synonym Blechnum contiguum, is a fern in the family Blechnaceae. The specific epithet refers to the contiguous lobes of the fronds.
Parablechnum howeanum, synonym Blechnum howeanum, is a fern in the family Blechnaceae. The specific epithet refers to the locality to which it is endemic.
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.
Diploblechnum fraseri, synonym Blechnum fraseri, known commonly as the miniature tree fern and by its Māori name maukurangi, is a species of fern in the family Blechnaceae native to New Zealand, Malesia and Taiwan.
Pseudolycopodiella caroliniana, known as slender bog club-moss, is a species of lycophyte in the family Lycopodiaceae. The genus Pseudolycopodiella is accepted in the Flora of North America and the Pteridophyte Phylogeny Group classification of 2016, but not in other classifications, which submerge the genus in Lycopodiella. The species has a discontinuous distribution, being native to the eastern United States and to parts of eastern Asia.
Mickelopteris is a genus of ferns in the subfamily Cheilanthoideae of the family Pteridaceae with a single species Mickelopteris cordata. Synonyms include Parahemionitis cordata and Hemionitis cordataRoxb. ex Hook. & Grev. The species is native to south-eastern Asia, from India to Taiwan and the Philippines.
