Contribution
Pelucha trifida – a case study in Asteraceae-Asteroideae on the value of stylar characters analysed in detail
Erbar, Claudia
Plant Diversity and Evolution Volume 132 No. 1 (2020), p. 57 - 86
publié: Mar 26, 2020
publication en ligne: Jan 21, 2020
manuscrit accepté: Jul 12, 2019
manuscrit reçu: May 28, 2019
DOI: 10.1127/pde/2019/0132-0089
ArtNo. ESP145013201002, Prix: 29.00 €
Abstract
The monospecific genus Pelucha (endemic to the Mexican islands in the Gulf of California and the nearby coast of Baja California) has been assigned to Inuleae (Inulinae or Plucheinae) or, more recently, to Heliantheae/Helenieae. Both affiliations were justified by style characters (“inuloid” versus “asteroid” arrangement of stigmatic papillae, i.e. marginal stigmatic bands confluent apically or separate throughout), although the style were never imaged in a paper. To eliminate these inconsistencies concerning in particular the arrangement of the stigmatic papillae, this paper deals with the style morphology of Pelucha in detail, studied by SEM and histological sections. The style of Pelucha trifida is assigned to the Mutisia-style type (acute stylar branches covered by stylar hairs extending halfway down their length and stigmatic tissue arranged in two marginal bands that become confluent apically). This style type of Pelucha that otherwise is not found within the “Heliantheae alliance” is in agreement with other features (pollen grains, absence of phytomelanin deposition) and supports an intermediate position between Inuleae and the phytomelanic fruit clade (PF clade sensu Panero & Croizat 2016) within the “Heliantheae alliance”.
Mots-clefs
Pelucha • Asteraceae • style morphology • SEM, histology • secondary pollen presentation