Latest Articles from PhytoKeys Latest 6 Articles from PhytoKeys https://phytokeys.pensoft.net/ Fri, 29 Mar 2024 08:02:18 +0200 Pensoft FeedCreator https://phytokeys.pensoft.net/i/logo.jpg Latest Articles from PhytoKeys https://phytokeys.pensoft.net/ Taxonomic dissection based on molecular evidence of the Eriosyce curvispina complex (Cactaceae): identifying nine endemic species from Central Chile https://phytokeys.pensoft.net/article/107403/ PhytoKeys 237: 117-139

DOI: 10.3897/phytokeys.237.107403

Authors: Helmut E. Walter, Arón Cádiz-Véliz, Beatriz M. Meriño, Heidy M. Villalobos-Barrantes, Pablo C. Guerrero

Abstract: Chile’s distinctive flora, geographical isolation, and complex topography collectively contribute to a notable endemic species diversity, particularly within central regions identified as critical areas for biodiversity conservation. The cactus genus Eriosyce, as currently circumscribed, encompasses seven sections, with Eriosyce sect. Horridocatus presenting a notably complex species group. This study investigates the E. curvispina complex, a member of the Notocacteae tribe common in central Chile, by incorporating new populations and examining phylogenetic relationships using four plastid and one nuclear molecular marker. The phylogenetic analysis of sampled individuals identified nine independent lineages, each warranting recognition at the species rank. Despite minimal morphological differences among taxa, morphological characters were utilized to support and stabilize the DNA-based phylogenetic hypothesis. The results highlight the high taxonomic diversity in these cactus lineages and have implications for the classification of the E. curvispina complex, including new combinations and proposals of conservation status.

HTML

XML

PDF

]]>
Research Article Mon, 22 Jan 2024 16:36:50 +0200
Phylogenetic relationships in Coryphantha and implications on Pelecyphora and Escobaria (Cacteae, Cactoideae, Cactaceae) https://phytokeys.pensoft.net/article/75739/ PhytoKeys 188: 115-165

DOI: 10.3897/phytokeys.188.75739

Authors: Daniel Sánchez, Balbina Vázquez-Benítez, Monserrat Vázquez-Sánchez, David Aquino, Salvador Arias

Abstract: The genus Coryphantha includes plants with globose to cylindrical stems bearing furrowed tubercles, flowers arising at the apex, and seeds with flattened testa cells. Coryphantha is the second richest genus in the tribe Cacteae. Nevertheless, the genus lacks a phylogenetic framework. The limits of Coryphantha with its sister genus Escobaria and the infrageneric classification of Coryphantha have not been evaluated in a phylogenetic study. In this study we analyzed five chloroplast regions (matK, rbcL, psbA-trnH, rpl16, and trnL-F) using Bayesian phylogenetic analysis. We included 44 species of Coryphantha and 43 additional species of the tribe Cacteae. Our results support the monophyly of Coryphantha by excluding C. macromeris. Escobaria + Pelecyphora + C. macromeris are corroborated as the sister group of Coryphantha. Within Coryphantha our phylogenetic analyses recovered two main clades containing seven subclades, and we propose to recognize those as two subgenera and seven sections, respectively. Also, a new delimitation of Pelecyphora including C. macromeris and all species previously included in Escobaria is proposed. To accommodate this new delimitation 25 new combinations are proposed. The seven subclades recovered within Coryphantha are morphologically and geographically congruent, and partially agree with the traditional classification of this genus.

HTML

XML

PDF

]]>
Research Article Fri, 21 Jan 2022 10:48:45 +0200
Evaluating the monophyly of Mammillaria series Supertextae (Cactaceae) https://phytokeys.pensoft.net/article/62915/ PhytoKeys 177: 25-42

DOI: 10.3897/phytokeys.177.62915

Authors: Cristian R. Cervantes, Silvia Hinojosa-Alvarez, Ana Wegier, Ulises Rosas, Salvador Arias

Abstract: Mammillaria (Cactaceae) taxonomy has been historically problematic due to the morphological variability and sympatry of the species. This has led to several proposals for infrageneric classification, including subgeneric, section and series categories. Mammillaria ser. Supertextae is one of 15 series and is made up of a variable set of species that are mainly distributed in southern Mexico and Central America. However, the phylogenetic relationships within M. ser. Supertextae and its relationship to other Mammillaria taxa are far from fully understood. Here we attempt to elucidate these relationships using complete terminal sampling and newly obtained chloroplast marker sequences and comparing them to Mammillaria species sequences from GenBank. Our phylogenetic analyses showed that M. ser. Supertextae comprises a well-supported monophyletic group that diverged approximately 2.1 Mya and has M. ser. Polyacanthae as its sister group; however, relationships within M. ser. Supertextae remain unresolved. The topology obtained within M. ser. Supertextae must also be interpreted under the distribution shared by these taxa, but it is difficult to differentiate ancestral polymorphisms from possible introgression, given the short time elapsed and the markers used. Our results show that the infrageneric units of M. haageana and M. albilanata can be considered independent evolutionary units. We also suggest that the relationship between M. haageana and M. albilanata is convoluted because their distribution overlaps (mainly towards southern Mexico), with genetic differences that possibly indicate they represent more than two taxonomic entities. One possible explanation is that there could still be gene flow between these taxa, and we might be witnessing an ongoing speciation process.

HTML

XML

PDF

]]>
Research Article Wed, 28 Apr 2021 10:26:21 +0300
Phylogenetics of Leptocereus (Cactaceae) on Hispaniola: clarifying species limits in the L. weingartianus complex and a new species from the Sierra de Bahoruco https://phytokeys.pensoft.net/article/59497/ PhytoKeys 172: 17-37

DOI: 10.3897/phytokeys.172.59497

Authors: Lucas C. Majure, Yuley Encarnación, Teodoro Clase, Brígido Peguero, Kelly Ho, Duniel Barrios

Abstract: The Antillean genus Leptocereus represents an in-situ radiation among the Greater and Lesser Antilles of 19 currently recognized species. Extensive fieldwork carried out in the Dominican Republic over recent years has revealed that the species limits of Leptocereus of Hispaniola are more complex than previously thought. There are four currently recognized species that occur on the island, L. demissus, L. paniculatus, L. undulosus and L. weingartianus. We evaluate species limits in this group based on DNA sequence data and phylogenetic analysis, morphological characters and a survey of herbarium specimens from across Hispaniola. Based on our analyses, it is clear that at least five species occur on the island of Hispaniola, with the new species from Sierra de Bahoruco, L. velozianus, described here. We provide an identification key, distribution maps and photographic plates for all species on Hispaniola based on our own fieldwork and the study of herbarium specimens. The description of yet another species of Leptocereus on Hispaniola reiterates the importance of the poorly studied, but yet biodiverse, seasonally dry tropical forest in the Antilles.

HTML

XML

PDF

]]>
Research Article Fri, 29 Jan 2021 13:42:58 +0200
Systematic relevance of pollen morphology in tribe Hylocereeae (Cactaceae) https://phytokeys.pensoft.net/article/35842/ PhytoKeys 128: 121-140

DOI: 10.3897/phytokeys.128.35842

Authors: Catalina Ruiz-Domínguez, Andrew P. Vovides, Victoria Sosa

Abstract: Hylocereeae is one of the nine tribes in the subfamily Cactoideae (Cactaceae), for which the limits and recognition of genera have been controversial. Essentially, this group comprises epiphytic and hemiepiphytic genera with stems modified as climbing structures. The aim of this paper is to examine pollen attributes in representative species of genera of Hylocereeae, focusing on Selenicereus whose current circumscription comprises Hylocereus and three Weberocereus species, to find whether significant potentially apomorphic and/or autapomorphic systematic characters can be discovered. Utilizing SEM and light microscopy, 25 pollen characters were observed and measured. Tribe Hylocereeae is stenopalynous, with pollen grains isopolar and radially symmetrical monads, mostly tricolpate, except in Kimnachia, Pseudoripsalis and Weberocereus, whose pollen grains are pantocolpate. Seven attributes (five qualitative and two continuous) exhibited useful variation and were coded. The character of brevicolpate pollen grains was shared by Kimnachia ramulosa and Pseudorhipsalis amazonica. Convex quadrangular outline in the polar view was shared by Weberocereus tunilla and S. glaber. The absence of spinules on the exine was shared by S. minutiflorus and S. stenopterus. The largest pollen grain, found in Selenicereus megalanthus, might be correlated with polyploidy. Selenicereus is the taxon with the highest variation in pollen attributes, including species with an exine with or without spinules and variable polar area index and shape (subprolate or oblate-spheroidal).

HTML

XML

PDF

]]>
Research Article Mon, 19 Aug 2019 11:19:01 +0300
Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae https://phytokeys.pensoft.net/article/26856/ PhytoKeys 111: 31-59

DOI: 10.3897/phytokeys.111.26856

Authors: Mario Daniel Vargas-Luna, Patricia Hernández-Ledesma, Lucas Charles Majure, Raúl Puente-Martínez, Héctor Manuel Hernández Macías, Rolando Tenoch Bárcenas Luna

Abstract: Molecular phylogenetic studies of the six currently accepted species in the genus Echinocactus have partially clarified certain aspects of its phylogeny. Most of the studies lack a complete sampling of Echinocactus and are based only in one source of data. Phylogenetic uncertainties in Echinocactus, such as the recognition of Homalocephala as a different genus from Echinocactus, the exclusion of E. grusonii or the affinities of E. polycephalus, are here resolved. Phylogenetic relationships of Echinocactus were reconstructed with a maximum parsimony, a maximum likelihood and a Bayesian approach including 42 morphological characters, four chloroplast markers (atpB-rbcL, trnH-psbA, trnL-trnF and trnK/matK) and two nuclear genes. The utility of these two nuclear regions related to the betalain cycles (DODA and 5GT) are explored and discussed in relation to their potential as phylogenetic markers. Concatenated analyses with morphological and molecular data sets, plus 13 indels (2847 characters and 26 taxa), show general agreement with previous independent phylogenetic proposals but with strong support in order to propose the recognition of a reduced Echinocactus and the recognition of Homalocephala at the generic level. These results recovered a polyphyletic Echinocactus as currently defined. The here-named HEA clade, recovers the species of Homalocephala, Echinocacuts and Astrophytum as a monophyletic group with strong internal support. The Homalocephala (H. texensis, H. parryi and H. polycephala), was recovered as sister to the Echinocactus clade (E. platyacanthus and E. horizonthalonius), plus the Astrophytum clade. Consequently, we propose here to recognise a monophyletic Echinocactus and a monophyletic Homalocephala as two distinct genera with their own molecular and morphological synapomorphies. The evolution of some morphological characters supporting these clades are discussed, the necessary new taxonomic combinations for Homalocephala are proposed and an identification key for the genera, the species and the subspecies of the HEA clade are presented.

HTML

XML

PDF

]]>
Research Article Tue, 13 Nov 2018 12:09:43 +0200