Search results for "Isoetaceae"
showing 10 items of 15 documents
Clarifying the nomenclature of some Euro-Mediterranean quillworts ( Isoetes , Isoetaceae): Indicator species and species of conservation concern
2018
International audience; To stabilize the application of some names in the genus Isoetes in the Mediterranean biodiversity hotspot, we studied herbarium specimens and imaged spores with scanning electron microscopy, with special reference to those taxa in the I. lon‐gissima and I. histrix groups that were described from France, Algeria and Turkey, and are in need of a taxonomic revision. The following names are lectotypified: I. adspersa, I. boryana, I. delalandei, and I. viollaei. Holotypes of I. perralderiana and I. olympica were ascertained. We conclude that I. boryana (listed in the “Bern Convention” and in the European Union “Habitats” Directive) justifies consideration at species rank,…
The genus isoetes (Isoetaceae): A provisional checklist of the accepted and unresolved taxa
2016
Isoetes is a widely distributed lycophyte genus of at least 200 species occurring in diverse habitats. The species can be difficult to identify because Isoetes, with its apparent simplicity of form and conserved morphology, provides few diagnostic features to reliably distinguish its species. The last worldwide monograph, published nearly a century ago, listed 77 taxa. The first step in producing a flora or monograph of all known species of a genus is to compile a list of the acceptable species names. The list presented here is a compilation of 192 accepted names representing taxa from regions around the world: chromosome numbers were assigned to 101 of them, with polyploidy settled on 46.7…
Isoëtes sabatina (Isoëtaceae, Lycopodiopsida). Taxonomic distinctness and preliminary ecological insights
2021
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 wa…
The genus Isoëtes L. (Lycophyta, Isoëtaceae): Synthesis of karyological data
2001
Summary A synthesis of relevant karyological data regarding the genus Isoetes is given, with an up-to-date check list of chromosome numbers including 152 records referring to 67 taxa (62 species and 5 infraspecific taxa) and 16 hybrids. Total of different chromosome counts (considering two or more cytotypes for certain taxa, excluding hybrids) is 80. Probable base number is x = 11, even though x = 10 and x = 12 have been proposed for certain species. On the basis of data here summarized, the mean percentage of polyploidy is 61.2%; 31 taxa are diploids (38.8%), 28 are tetraploids (35.0%), 8 are hexaploids (10.0%), with a few species each which are tri-, penta-, octo-, deca- and dodeca-ploids…
Disentangling Isoetes setacea and removing threats to Isoetes echinospora
2015
The name Isoetes setacea has been applied to two different species, causing nomenclatural and taxonomic confusion. Some authors have rejected it on that account, yet it is currently used in a sense that is incompatible with its type. That type represents one of two similar species, I. echinospora and I. lacustris, which still today grow together at the type locality. An epitype is designated here, ensuring that I. setacea is sunk in synonymy under I. lacustris. A second name potentially threatening I. echinospora is I. tenella. It is currently regarded as a synonym of I. lacustris, but its type, a plate in Flora Danica, cannot be confidently identified, nor are there any specimens associate…
A conspectus of and key to GreekIsoetes(Isoetaceae), based on a reassessment of Haussknecht's gatherings of 1885
2015
The three Isoetes species recorded from Thessalia (Thessaly) in N Greece by Haussknecht, in 1899, under the names I. setacea, I. heldreichii, and I. phrygia, were reassessed using megaspore and microspore ornamentation in addition to macromorphological features. “Isoetes setacea” is not the SW European I. delilei to which the name I. setacea was generally misapplied, nor “I. echinospora” as it has been called due to a misunderstanding, but a so far undescribed species here named I. haussknechtii; it has not been found again in Haussknecht’s locality but has recently turned up in Peloponnisos and the E Aegean Islands. I. heldreichii, described from Haussknecht’s gathering, is apparently exti…
A critical conspectus of ItalianIsoetes(Isoetaceae)
2014
The work on the Isoetaceae account for the Critical Flora of Italy has resulted in a new, synonymic inventory of Italian Isoetes taxa, based on herbarium studies, observation by scanning electron microscopy and critical re-examination of the previously published works. Ten species are listed. The names I. longissima and I. gymnocarpa are restored as correct, to replace I. velata and I. subinermis, respectively. Eighteen lectotypes, one epitype and one neotype are designated. A dichotomous key to Italian taxa is provided.
Isoëtes sabatina (IsoëtaceaeLycopodiophyta), a new aquatic species from central Italy
2013
The new species Isoetes sabatina is described and illustrated. Morphological, anatomical, and ecological characters are given. It differs from the similar I. echinospora by several characters, such as megaspore ornamentation and size, microspore size, velum extension and form, and also for its ecology. A table showing the main differential characters of the new species compared with those of the other European aquatic species is presented. So far, the species is known from a single locality (Bracciano Lake, central Italy), having a peculiar ecology and within the Mediterranean bioclimate.
Morphological observations on the co-occurring geophytes Isoetes duriei Bory (Lycophyta, Isoetaceae) and Romulea columnae Sebast. et Mauri (Anthophyt…
2003
Some preliminary observations on the morphoplogy and leaf anatomy of two geophytes, Isoetes duriei and Romulea columnae, co-occurring in a Mediterranean temporary pond, have been reported. The species examined possess characters favourable to the survival of both flooded and arid conditions. The adaptive traits to flooding appear plastic in R. columnae, while I. duriei is “structurally” an aquatic plant. Evolutionary and ecological aspects are briefly discussed.
A contribution to the phylogeny and biogeography of the genus Isoetes (Isoetaceae, Lycopodiidae) in the Mediterranean region
2019
To better understand the phylogeny of Isoetes species in the Mediterranean region, sequences of the second intron of a LFY-like homolog were determined for six populations of three Mediterranean Isoetes species and analyzed with other LFY and ITS sequences of Euro-Mediterranean species available in GenBank. Nomenclature of selected species was updated according to recent literature. Investigations of voucher specimens from previously sequenced taxa revealed that a specimen of I. histrix from Crete, Greece used in several previous molecular studies is probably I. phrygia. Analysis of the limited LFY and ITS DNA sequence data presented here agrees with the organization of Mediterranean specie…