The Neotropical Croton sect. Geiseleria (Euphorbiaceae): Classification Update, Phylogenetic Framework, and Seven New Species from South America

Abstract

A revised assessment of Croton L. sect. Geiseleria (A. Gray) Baill. is provided. The section as now circumscribed includes 84 species ranging across warm areas of the Americas. A nuclear ITS phylogeny of 150 accessions from 83 species and a chloroplast trnL-F phylogeny of 89 accessions from 65 species were generated to confirm correct phylogenetic placement of the species and to determine if any species previously included in the section should now be excluded. Seven new species are described, and we present a taxonomic synopsis that lists all currently accepted species along with their synonyms, distributions, and pertinent comments. We also recognize four subsections within Croton sect. Geiseleria and list their corresponding species. Based on both morphological and molecular criteria, we now recognize C. lagunillae Croizat as a distinct species, rather than as a variety of C. guildingii Griseb. (now treated as C. suavis Kunth), and we treat C. ramillatus Croizat var. magniglandulifer V. W. Steinm. as a species, C. magniglandulifer (V. W. Steinm.) B. W. van Ee. We also exclude C. tetradenius Baill. from Croton sect. Geiseleria (A. Gray) Baill. along with related species such as C. pulegiodorus Baill. and C. leptobotryus Müll. Arg., which are either members of Croton sect. Adenophylli Griseb. or else may merit new sectional status. We also exclude C. waltherioides Urb., although it is not clear to which section of Croton it belongs.

Croton restingae sp. nov. (Euphorbiaceae), a new species of section Adenophylli from the state of Rio de Janeiro, Brazil, and its phylogenetic relationships

“…We included a newly generated ITS sequence of the new species in a molecular dataset with 38 species of Croton: 27 in section Adenophylli, five in section Cyclostigma Griseb., and three (C. tetradenius Baill., C. pulegiodorus Baill. and C. chimboracensis P.E.Berry & Riina) with uncertain sectional placement, but frequently allied to section Adenophylli in previous studies (Riina et al 2021;. As outgroups within Croton, we included C. cupreatus Croizat, C. argenteus L. and C. sampatik Müll.Arg.…”

Antimicrobial Activity the Essential Oil from Croton pluriglandulosus Carn. Leaves against Microorganisms of Clinical Interest

“…It has many trichomes on the leaves, latex, and acropeculiar glands. In Brazil, it is predominantly found in regions with the caatinga biome [14] Given the phytotherapeutic and microbial potential of species belonging to the Croton genus, the present work aimed to understand and determine the activity and mechanisms of action of the essential oil extracted from the leaves of Croton pluriglandulosus (CpOE) Carn.-Torres & Riina, which is poorly studied regarding the control of microorganisms in planktonic and biofilm form.…”

Bahiana, a new Euphorbiaceae (Acalyphoideae) genus from seasonally dry forest in northeastern Brazil, corroborated by molecular and morphological evidence

“…(Zhou & al., 2017) from the Yuanjiang dry‐hot valley in Yunnan, China. Many species from these ecosystems have also been recently described (e.g., Mateo‐Ramírez & Riina, 2020; Moreira & al., 2020; Haevermans & Hetterscheid, 2021; Riina & al., 2021; Montero‐Muñoz & al., 2022). This is evidence of the importance of the SDTF biome for Euphorbiaceae diversity and the need to intensify conservation and sampling efforts in this region.…”