The genus Isoetes (Isoetaceae): a provisional checklist of the accepted and unresolved taxa

Abstract

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%. Distribution mapping of the accepted species indicates that South America is the center of diversity for Isoetes and species diversity is the highest in temperate regions. Many of the species on this list are rare and have limited ranges. The list of taxa can be used to initiate floristic studies and conservation efforts in keeping with the target goals of the Global Strategy for Plant Conservation.

Clarifying the nomenclature of some Euro‐Mediterranean quillworts (Isoetes, Isoetaceae): Indicator species and species of conservation concern

“…SEM spore images are presented and commented upon whenever appropriate. Troia & al., 2016). The main distinguishing character shared by all of these taxa is the megaspore ornamentation.…”

Isoetes nana, a new species from the coastal mountains of southeastern Brazil

“…The genus is distributed worldwide and comprises approximately 250 species (Troia et al 2016). In South America, Isoetes is represented by 64 species (Troia et al 2016).…”

“…The genus is distributed worldwide and comprises approximately 250 species (Troia et al 2016). In South America, Isoetes is represented by 64 species (Troia et al 2016). The coastal mountains of southeastern Brazil represent one of the major centres of diversity and endemism in South America (Prado et al 2015).…”

Isoetes mississippiensis: A new quillwort from Mississippi, USA

“…Isoetes (Isoetaceae) is a cosmopolitan genus of heterosporous lycophytes containing 200–300 species (Hickey et al 2003; Troia et al 2016). Lycophytes have an extensive fossil record dating from the Devonian and a morphology so conserved that members of the genus Isoetes are recognized in the Triassic (Pigg 2001).…”

“…Lycophytes have an extensive fossil record dating from the Devonian and a morphology so conserved that members of the genus Isoetes are recognized in the Triassic (Pigg 2001). Extant species are widely distributed from the tropics to the sub-arctic (Troia et al 2016). They range in habitat from evergreen aquatics to seasonal terrestrials.…”