A morphometric study of three closely related taxa in the European Isoetes velata complex

Abstract

Isoetes velata A. Braun is an amphibious plant with Mediterranean and Ibero‐Atlantic distribution, showing marked morphological variability. Within the same geographical area, closely related restricted‐range taxa are also present, including I. velata ssp. asturicense (restricted to mountainous areas of the north‐west Iberian Peninsula) and I. boryana (restricted to the southern French Atlantic coast). These related taxa have unclear taxonomy and are both threatened. We performed a morphometric study of specimens of the three taxa. Our results suggest that I. velata ssp. asturicense is better considered as a distinct species, I. asturicense Laínz (Laínz), distinguishable from the other two taxa by mean megaspore length (N ≥ 30) < 360 µm. In contrast, our results do not support consideration of I. boryana as a separate species, and we here propose that this taxon be considered as a variety, I. velata A. Braun var. boryana M.I. Romero & C. Real stat. nov. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 148, 459–464.

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

“…1). The microspore of I. boryana shown in Romero & Real (2005) is different, however, from the microspore of I. longissima (the two are shown side by side in the same article). Prada & Rolleri (2005) found another character separating I. boryana from I. velata/longissima, i.e., the lack of intercellular pectic protuberances (IPP) in the cells of the translacunar diaphragms of the microphylls.…”

“…Some authors described the microspores of I. boryana as either smooth (Hy, 1894;Berthet & Lecocq, 1977;Rolleri & Prada, 2007) or very minutely scabrid (Berthet & Lecoq, 1977;Jermy & Akeroyd, 1993) or sub-papillose (Rolleri & Prada, 2007). Prelli (2002) and Romero & Real (2005), however, reported echinate miscropores, similar to those of I. longissima. Our investigations found only non-echinate microspores (Fig.…”

“…Taxa from Spain, Italy and Greece have been studied by several authors in recent years (Prada, 1983;Romero & al. 2004;Romero & Real, 2005;Troia & Greuter, 2014, 2015b, and all the other names in those groups have already been typified.…”

“…The taxonomic status of I. boryana, a species of great conservation concern, is especially unclear. It is uncertain if it is a "good species" (as reported in the "Habitats" Directive, and by other sources such as Christenhusz & Raab-Straube, 2013) or a synonym of other species (as suggested by, e.g., Prelli, 2002, andReal, 2005).…”

Habitat differentiation and geographic separation of Isoetes velata populations in central Iberian Peninsula

“…Based on morphometric differences together with other distinguishing characteristics as habitat, Romero & Real (2005) have suggested that I. asturicense (Laínz) Laínz should be considered as separate species of I. velata. In this work, megaspore characteristics and habitat attributes in Isoetes populations from the western Iberian Peninsula, where both I. velata susbp.…”