Abstract
The basal position of the small American genus Microtea within the core Caryophyllales was suggested only recently in accordance with molecular phylogeny. However, the specific relationships within the genus were not traced. The results of our phylogenetic analysis based on the matK chloroplast gene suggest the monophyly of Microtea, and Ancistrocarpus and other related genera should be included in it. Microtea is divided into two major sister clades: clade A consisting of M.glochidiata, M.maypurensis and M.tenuifolia, and clade B comprising M.debilis, M.sulcicaulis, M.scabrida, M.celosioides, and M.papillosa. The nrDNA dataset (ITS), although containing only a limited number of accessions, shows the same species number in clade A, and the remaining species studied (M.debilis, M.scabrida and M.celosioides) form clade B. Subgeneric status is assigned to clades A and B corresponding with the names Microteasubgen.Ancistrocarpus subgen. nov. and Microteasubgen.Microtea, respectively. The diagnostic characters at the subgeneric level are as follows: length of pedicels, number of flowers at each node, number of stamens and styles. A multivariate analysis of 13 distinguishing morphological characters supports the results of phylogenetic analysis. All species have similar pericarp and seed ultrasculpture and anatomy, and they share the reticulate pericarp surface (independent of presence or absence of finger-shaped outgrowths on its surface) and rugose or slightly alveolate seed ultrasculpture. On the basis of morphological characters, we accept 10 Microtea species. A checklist includes a new diagnostic key, morphological descriptions and distribution patterns of each species. Galeniacelosioides is the oldest legitimate name available for the plants previously known as Microteapaniculata, for which the combination Microteacelosioides is validated here. The neotypes of Galeniacelosioides and Microteasprengelii were designated from the collections of Prinz Wied at BR. The name M.foliosa is discussed and finally synonymized with M.scabrida. The lectotypes of Ancistrocarpusmaypurensis (≡Microteamaypurensis), Microteadebilisvar.ovata (=M.debilis), M.glochidiata, M.maypurensisvar.angustifolia (=M.tenuifolia), M.glochidiataf.lanceolata (=M.maypurensis), M.longebracteata (=M.celosioides), M.paniculatavar.latifolia (=M.scabrida), M.portoricensis, M.scabrida, M.sulcicaulis, and Potamophilaparviflora (=M.maypurensis) are designated. Microteasulcicaulis is reported for the first time as native to Bolivia, and M.maypurensis is reported from Indonesia (Java), where it is found as an alien plant with an unclear invasion status.
Highlights
The genus Microtea Sw. was described by Swartz (1788) with one species, M. debilis Sw., native to the Lesser Antilles
Microtea is divided into two major sister clades: clade A consisting of M. glochidiata, M. maypurensis and M. tenuifolia, and clade B comprising M. debilis, M. sulcicaulis, M. scabrida, M. celosioides, and M. papillosa
Further new generic and species names were mostly based on the same reproductive characters (Roemer and Schultes 1820, Schrank 1821, Link 1821), but none of the genera allied to Microtea have been commonly accepted, and currently Microtea has been considered a single genus that includes all closely related taxa (e.g., Steudel 1841, Moquin-Tandon 1849, Urban 1885, Walter 1909, Rohwer 1993, Marchioretto and de Siqueira 1998)
Summary
The genus Microtea Sw. was described by Swartz (1788) with one species, M. debilis Sw., native to the Lesser Antilles (the Caribbean) The author placed it within the group “Pentandria–Digynia” due to the pentaphyllous perianth, five stamens, and two styles. According to the latest studies (Marchioretto and de Siqueira 1998, Hernández-Ledesma et al 2015), Microtea comprises 10–12 species distributed in Central and South America. They can be distinguished and classified by life history, presence of bracteoles by each flower, and morphology of the pericarp (e.g., Walter 1909, Marchioretto and de Siqueira 1998). Many important reproductive traits are still poorly studied in this genus, including the fruit and seed anatomy that has been depicted schematically only for M. debilis (Melikian 1993)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
