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Isoetes baodongii Y. F. Gu, Y. H. Yan & Yi J. Lu (Isoetaceae) is here described as a newly discovered, rare and endangered species of quillwort from eastern China. It has a basic diploid chromosome count of 2n = 22. Isoetes baodongii is similar to I. sinensis T. C. Palmer in its overall appearance and was previously misidentified as such. It differs from I. sinensis in its chromosome number and in megaspore ornamentation. In I. baodongii, both the proximal surface and distal surface of the megaspore are echinato-cristate, whereas in I. sinensis the proximal surface is echinate and the distal surface echinato-cristate. Microspores of I. baodongii have echinate ornamentation.

Isoetes jarmaniae sp. nov. is described as a new lycophyte endemic to Tasmania, Australia, where it is confined to peat-bound karstic wetlands in several river valleys in the south-west wilderness. While seemingly morphologically closest to I. drummondii, this quillwort has features that are globally uncommon in Isoetes and unknown in other Australasian taxa. Most notable are its markedly flattened, strongly recurved leaves and disproportionately large sporangium ligules that are more suggestive of South American than Australian taxa. As well, the exceptionally thin and wide (alate) megaspore equatorial ridge is swollen at suture intersections, presenting a slightly triangular shape suggestive of the Indian taxon I. udupiensis. The microspores of I. jarmaniae exhibit exceptionally, perhaps uniquely, fine-papillate ornamentation. An original key placing I. jarmaniae in context with the other Tasmanian Isoetes species is provided. This diminutive, apparently diploid species is evidently maintaining a self-sustaining population within a regionally unique habitat and small geographic range.

Establishing the geographical distribution limits of species may provide not only data to understand their range of adaptation to conservation proposals but also records of the dynamics in the vegetation across the time. Here we report the southernmost limit of the occurrence of Isoetes panamensis Maxon & C.V. Morton within a relict of the Cerrado in Paraná, Brazil. This find highlights the importance of fieldwork in relicts of the Cerrado to enhance the knowledge about the flora of Paraná and the vegetational dynamic of the Cerrado in the past.

Heterosporous sporangia discovered in Isoetes pantii Goswami & Arya are known as heterosporangia. Heterosporangia produce thousands of alete, monolete and trilete microspores and a few dozen megaspores. This trait is inherent within the genome of I pantii because plants collected from a location in South Gujarat also exhibit this feature. Additionally, initial collections and followup studies since 1966 have been consistently showing two types of megaspores within the heterosporangia. While microspores and megaspores develop in each and every hetrosporangium, additional unusual megaspores, variable in shape and size (180-220 micron), do not occur in all heterosporangia of all plants. These spores closely resembling fossil ancestral spores are being now termed as “Chalonospores”. Thus, a living spore genus Chalonospora is being named and defined as a spore discovered in a living plant which recall fossil ancestry of the genus but are never found in any other extant species of the genus. Since Chalanospores also originate from spore mother cells, as other microspores and megaspores do, this indicates that spore mother cells found in heterosporangia are genetically variable in expressions. Quite likely, a few megaspore mother cells must be possessing gene combinations with “revitalized relic DNA sequences”. As different types of chalonospres have been observed, variable gene combinations must be representing sporadic expressions of different lycopods of the vast geological past. Germination studies prove that these spores are endowed with different genetic make-up, as the gametophyte produced on soil culture produce unique single cell rhizoids with spiny outer layer. This apparent genomic reshuffle is related with frequently encountered chromosome breaks, translocations and irregular presence of 2n=36 –to 39 chromosomes in such plants. However, Isoetes pantii plants possess 2n=48 chromosomes with X-Y mechanism. No other species in the world flora of the genus has exhibited sex chromosomal mechanism and possessed n=12 chromosome series. With greater probability this appears plausible to imagine that naturally imposed chromosomal aberrations have rejuvenated genes which might have been regular expressions within the genome of some of the lycopods of Carboniferous and thereafter

In many cases over the years the diversity of Isoetes in India has been defined by inconsistent morphological analyses and questionable data. This has resulted in substantial confusion, dramaticall...

The hybrid between diploid Isoetes echinospora and tetraploid I. laurentiana is reported from six sites along the St. Lawrence River near Quebec City. Morphological characteristics and distinguishing features are identified, and the binomial I. ×blondeaui, hyb. nov. is proposed. All occurrences are in biogeographically significant freshwater tidal marsh habitat. The hybrid is expected to occur in small numbers within most large I. laurentiana populations.

Isoetes brochonii has possibly been subject to more taxonomic designations over the last century than any other European quillwort and most commonly has been put into synonymy with the widespread I...

A second population of the diploid Isoetes santacruzensis is reported. This extends the range of that newly described endemic of granite outcrop pools by approximately 100 kms southward into central Bolivia from its type location. Another distinct taxon has been detected in the vicinity of the new I. santacruzensis population. The morphology of probably tetraploid I. afloramientorum sp. nov. is described. A cluster of distinct taxa comparable to similar complexes seen in North America, Australia and northern Brazil may be present on Bolivian granite outcrops. There is an urgent need for field investigation of this unique and important habitat to determine the contemporary status and protection requirements of its rare and possibly endangered flora.

The Isoetes engelmannii complex of eastern North America consists of 30 taxa including 13 named species. Nine of the 17 hybrids within the complex (the largest group of Isoetes hybrids in the world) have been formally described. Those named hybrids are reviewed here in light of recent additions to and enhancements of the morphological and cytological evidence employed in their original description. The pedigree of three of these, I. ×brittonii, I. ×bruntonii and I. ×carltaylorii, is updated and clarified. Formal descriptions are proposed for two additional taxa: I. ×fernaldii, hyb. nov. (I. engelmannii × I. hyemalis) and I. ×karenae, hyb. nov. (I. appalachiana × engelmannii). The potential for a further eight hybrid combinations to occur in the wild is also addressed.

A new species of the genus Calamaria Boie, 1827, Calamaria arcanasp. nov., is described based on a single male specimen collected from Mt. Dadongshan, Guangdong, southern China. The new species can be distinguished from all known congeners by the significant genetic divergence in the mitochondrial cytochrome-b gene fragment (p-distance ≥ 13.9%), and morphologically by the combination of the following characters: (1) ten modified maxillary teeth; (2) four supralabials, second and third supralabials entering orbit; (3) preocular present; (4) mental not touching anterior chin shields; (5) six scales and shields surrounding the paraparietal; (6) 170 ventral scales; (7) 22 paired subcaudals; (8) tail not gradually tapering, abruptly tapering at the tip; (9) dorsal scales reduced to five rows above last subcaudal at tail; (10) dorsum of body and tail brownish; (11) dark collar on nuchal region absent; (12) two outermost dorsal scale rows light yellow with upper margins partly dark pigmented; (13) ventral scales immaculate, without dark outermost corners and pigmentation anteriorly; and (14) absence of distinct dark longitudinal line or scattered spots on the underside of tail. Calamaria arcanasp. nov., represents the fifth species of the genus recorded in China. Following the IUCN Red List Categories and Criteria, we propose the new species to be listed as Data Deficient.

Isoetes jarmaniae D.F.Brunt., G. Kantvilas & M. Garrett, sp. nov. (Figures 1, 4, 5, 6) Diagnosis:— A diminutive species restricted to alkaline seepage areas in Tasmanian buttongrass moorland and most similar to the larger Isoetes drummondii, from which it differs most conspicuously by its strongly recurved leaves, disproportionately large ligules and congested, boldly ornamented regulate-cristate to columnar, slightly triangular megaspores and finely papillate microspores. Type: — AUSTRALIA: Tasmania, Maxwell Valley near Lancelot Hill, 42°31’S 145°55’E, in alkaline pan, 190 m elevation, 26 April 1985, S. J. Jarman (holotype HO 314939!; isotype DFB! [fragment]). Description:— PLANTS: short (leaf rosette above corm en masse. Distribution and Habitat:— In coarse, peaty quartzite/ silica sand substrate in periodically inundated (flowing) seepage areas over limestone bedrock, with sparse associated vegetation; found only in southwestern Tasmania, Australia. Chromosome Number:— Inferred diploid (2 n =2x=22) by spore size conformity with cytologically confirmed diploid Tasmanian taxa: I. drummondii, I. elatior and I. gunnii (Marsden 1979, D.M. Britton pers. comm.). Etymology:— The epithet honours Dr. S. Jean Jarman of Hobart, Tasmania, who first collected this species and recognised it as unique. The vernacular name Limestone Quillwort is suggested, as per Tasmanian State Government (2021). Paratypes: — Tasmania: tributaries of the Giblin River, E of Lawson Range, 42°56’S 145°44’E, J. Jarman (HO 31378!); Maxwell Valley, 42°30’S 145°55’E, 190 m, 26April 1985, S. J. Jarman (HO 314082!); Maxwell River, 42°31’S 145°55’E, 200 m, 26 April 1985, M. J. Brown (HO 531819!); Middle Giblin River basin, 8 km NW of Mt Gaffney, 43°00’S 145°45’E, 30 m, 17 Feb. 1989, J. R. Croft 10114 & M. M. Richardson (AD, CANB, HO!); Alfhild Creek, Giblin River Valley, 43°03’S 145°43’E, Feb. 1989, L. Gilfedder (HO 114427!); Giblin River 43.0156°S 145.7467°E, M. Garrett s.n., 20 February 1994 (DFB!, OAC); Giblin River, 42°57’S 145°46’E, 20 m, 8 Jan 2005, G. Kantvilas & M. Garrett (HO 531818!); Giblin River valley, 42°56’S 145°45’E, 40 m, 18 Aug. 2016, M. Visoiu (HO 591035!); Maxwell River Valley, c. 700 m SW of Prince Rivulet, 42°29’S 145°55’E, 190 m, 12 Dec. 2017, M. F. de Salas 1915 (DFB (fragment)!, HO 590554!); Algonkian Rivulet valley, c. 800 m NW of junction with Ridge Creek, 42°27’S 145°57’E, 210 m, 12 Dec. 2017, M. F. de Salas 1903 (DFB (fragment)!, HO 590544!); Giblin Valley, c. 2.75 km SE of Pass Hill, 42°56’S 145°45’E, 40 m, 21 Mar 2018, M. F. de Salas 2005 (DFB (fragment)!, HO 593072!).

Isoetes amazonica and I. gardneriana were the first two species of the genus to be collected from Brazil. Isoetes amazonica was gathered by Richard Spruce in the Amazon basin near Santarém in the state of Pará in 1850. Isoetes gardneriana was collected by George Gardner in the current Dianópolis in Tocantins State in 1843. Despite being known for a long time by botanists, these species have not been recollected since then, which raised questions about their taxonomic recognition, current distribution ranges and conservation status. Fieldwork efforts led to the rediscovery of I. amazonica and I. gardneriana after 167 years. These collections enrich our understanding of their habitats and morphologies. We provide here re-descriptions for these species. Based on IUCN criteria, Isoetes amazonica and I. gardneriana should be assigned as data deficient (DD) and endangered (EN), respectively. The rediscovery of these species raises hopes that other areas in Amazon and Cerrado biomes harbour I. amazonica and I. gardneriana, respectively. This study will serve as a basis towards the conservation of these species.

Morphological, phytogeographic, ecological, preliminary genetic, and C-value evidence indicates that populations of Isoetes confined to freshwater tidal marsh habitats along the St. Lawrence River in Quebec, Canada, represent an undescribed endemic species, proposed here as Isoetes laurentiana sp. nov. The combination of short velum coverage (ca. 10%) over a plain (unstreaked) sporangium, broad (ca. 1.0 mm) erect leaves, small megaspores (ca. 459 μm) with more densely convoluted-reticulate, almost echinate ornamentation, and its occurrence within an exceptional habitat, readily distinguish I. laurentiana from I. tuckermanii A.Braun with which it was formerly combined. Isoetes laurentiana is one of a series of endemic taxa of the floristically extraordinary St. Lawrence River estuary. Some populations of I. laurentiana are immense; in cultivation it demonstrates the capacity for prolific production of new individuals, which is presumably necessary to sustain such local abundance. Isoetes laurentiana is of national and global phytogeographic significance, but is not considered to represent a species at risk according to standards from the International Union for Conservation of Nature.

Isoetes dubsiisp. nov. and I. santacruzensissp. nov., two new species from lowland areas in South America, are described, illustrated and compared to similar species. Isoetes dubsii can be distinguished from other species of the Brazilian Pantanal wetlands by a set of characters including leaves that are long, flexuous and trigonal in transverse section, tri-lobate stems, rudimentary velum, pustulate megaspores of 310‒390 µm diameter and laesurae of the megaspore at least four times wider than high. Isoetes santacruzensis has flexuous, filiform leaves, 0.4–0.8 mm wide at mid length and reaching up to 15 cm long, black or reddish-black sporangia, sclerified phyllopodia and sparsely verrucate megaspores of 320‒390 µm in diameter. We also include a key for species from the Brazilian Pantanal wetlands and Bolivia and spore images for all species that are discussed. Isoetes dubsii and I. santacruzensis are only known from their type localities and they may deserve special attention concerning their conservation status. However, based on our current knowledge on these species and according to IUCN Red List criteria, they are assessed here as data deficient (DD).

Isoetes L. is a nearly cosmopolitan rhizomorphic lycopsid genus fundamental to disentangling plant evolution because of its singular position in the Plantae kingdom. A threatened Amazonian species recently described is I. cangae, inhabiting an oligotrophic upland lake over an iron-rich region facing substantial environmental alterations. In this study, we aim to optimize a reproduction protocol that can assist in the conservation efforts of Isoetes species in tropical areas. We observed an average of 126 megaspores or 318,000 microspores per sporangia in field-collected plants. We obtained an elevated percentage of sporelings (63%) from an in vitro mixed culture of mega- and microspores. In addition, we recovered a large number of sporelings around adult plants after cultivating them over quartzite sand and distilled water. The megaspore nutrient reserve ensured longstanding sporeling growth and development in these environmental conditions. However, the sporeling growth rate increased when they were planted over their original lake sediments or over an organic substrate, with nonsignificant differences between the substrates. An increase in temperature also increased the sporeling growth rate. Together with the very low sporeling mortality, these results suggest that I. cangae is a resilient species able to grow and colonize environments with low trophic characteristics with a range of substrates and temperature regimes. The protocols established in this study could be useful for the ex situ propagation and growth of a large number of sporelings, representing critical steps towards the population rescue and conservation of tropical Isoetes species.

1) Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres. 2) Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina. 3) To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species was carried out to describe its genetic distinctness, physical and chemical requirements and companion species. 4) The phylogenetic position of I. sabatina was investigated by applying standard DNA barcoding methods. Simultaneously, during summer 2019, the physical and chemical features of water and sediments of the I. sabatina population and five small Alpine lakes colonized by Isoëtes echinospora – a supposed close relative – were characterized. These data were then compared with the available data on the trophic requirements of the target obligate aquatic Isoëtes, together with Isoëtes lacustris and Isoëtes malinverniana. 5) The present survey confirmed the taxonomic and ecological distinctness of I. sabatina – providing the first evidence of genetic differentiation from I. echinospora. Isoëtes sabatina grows in waters with temperature, conductivity and total alkalinity up to 30°C, 561 μS cm−1 and 3.45 meq L−1, respectively. 6) The edaphic requirements of I. sabatina confirm its outstanding conservation value, and this study offers a basic understanding of how to prevent its extinction. Now, all possible actions must be taken immediately to save this species.

Despite an increase in studies involving lycophytes and ferns in recent years, Maranhão is still one of the northeastern states with a poorly known flora, mainly due to low sampling. For Chapada das Mesas National Park, a protected conservation unit in the Cerrado maranhense with phytophysiognomies that favor floristic diversity, there are no floristic studies about lycophytes. This study aimed to conduct the floristic inventory and taxonomic study of lycophytes in Chapada das Mesas National Park. Three collection expeditions, of three days each, were made between March 2017 and June 2018. Three families of lycophytes represented by three genera and six species were identified in the study area. The most diverse family was Selaginellaceae with four species: Selaginella conduplicata, S. erythropus (Mart.) Spring, S. radiata (Aubl.) Baker and S. simplex Baker. The other two families, Isoëtaceae and Lycopodiaceae, had one species each, Isoëtes sp. and Palhinhaea cernua (L.) Franco & Vasc. This study also reports two new record for the Brazilian Cerrado phytogeographic domain, S. conduplicate and S. radiata, of which the first is a new record for Maranhão State. Most specimens were found in riparian forest on rocky outcrops. Resumo: Embora as pesquisas envolvendo o estudo de licófitas e samambaias tenham crescido nos últimos anos, o Maranhão ainda é um dos Estados do Nordeste com sua flora menos conhecida em virtude, principalmente, da baixa amostragem. O Parque Nacional (PARNA) Chapada das Mesas, apesar de tratar-se de uma unidade de conservação protegida no Cerrado maranhense e abrigar fitofisionomias que são propícias à diversidade florística, ainda não possui estudos sobre a diversidade florística de licófitas. Este estudo teve como objetivo geral fazer um inventário e estudo florístico e taxonômico de licófitas para o PARNA Chapada das Mesas. Foram realizadas três expedições para coletas de material entre março 2017 e junho 2018 com duração de três dias cada. Na área de estudo foram identificadas as três famílias de licófitas representadas por três gêneros e seis espécies. A família com maior diversidade foi Selaginellaceae com quatro espécies Selaginella conduplicata, S. erythropus, S. radiata e S. simplex. As outras duas, Isoëtaceae e Lycopodiaceae com uma espécie cada, Isoëtes sp., e Palhinhaea cernua. Nesse estudo também são relatados dois novos registros para o domínio fitogeográfico do Cerrado, S. conduplicata e S. radiata, sendo a primeira um novo registro para o Estado do Maranhão. A maioria dos espécimes foi encontrada em ambientes de matas ciliares crescendo sobre afloramento rochoso.

A new umbellate ornamentation pattern is described in Isoetes megaspores based on scanning electron microscopy and thorough comparisons with sculptural patterns documented in lycophytes and ferns. The umbellate ornamentation is quite distinct from other vertically projected megaspore sculptural patterns (baculate, clavate, gemmulate, pustulate, tuberculate, saccate and verrucate). In addition, megaspore ornamentations described previously for I. dixitei as tuberculate or pustulate have now been corrected as umbellate. This species also possesses a rudimentary velum and internal pigmentation in sporangial wall which has not been reported in other Indian species of the genus. Further, this taxa has a range restricted to the Western Ghats and is confined to a higher elevational range than Indian species characterised by vertically projected megaspore surface ornamentation patterns.

Within the Lycopodiopsida, Lycopodiaceae is a medium-sized family of lycophytes in New Zealand with five genera and 11 indigenous species, and Isoetaceae is a small family with one genus and two species. Fourteen lectotypes are chosen for basionyms relevant to New Zealand – Isoetes alpina Kirk, Lycopodium australianum Herter, L. billardierei Spring, L. consimile Colenso, L. curvifolium Colenso, L. distans Colenso, L. drummondii Spring, L. lessonianum A.Rich., L. novozealandicum Colenso, L. sanguisorba Spring, L. serpentinum Kunze, L. varium var. gracile Kirk, L. varium var. polaris Kirk, and Phylloglossum drummondii Kunze. No type material has been found for Lycopodium decurrens Colenso, and the type for this remains undesignated. Lectotypes need to be chosen for all names at specific and subspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

The unique morphology of quillworts has received limited attention, and such studies have been limited to only a few species. Our extensive field work during the past two decades has revealed variation in the structures of the plant, including the rhizomorph, scales, phyllopodia, and abscission caps. Polarity of the axes of southeastern quillwort rhizomorphs varies from discoid (most species), to elongate, to upright with axis branching in several species. In species of intermittent streams, these branched rhizomorphs produce plantlets that break off in running water. Scales are tiny brown or black structures in alternating whorls with sporophylls (leaves). They are often overlooked and easily removed when rinsing specimens. Found in most southeastern terrestrial/amphibious species, scales are absent from aquatic species. Scales are distinct from phyllopodia, the sclerified bases of sporophylls, but intermediates between scales and phyllopodia occur. Not all species with scales have phyllopodia....