Carex huancabambica (Cyperaceae), a new species from the Peruvian and Ecuadorian Andes

161 Carex huancabambica (Cyperaceae), a new species from the Peruvian and Ecuadorian Andes Luis González-Gallego1, Carmen Benítez-Benítez2, Anton A. Reznicek3, Asunción Cano4, Nora H. Oleas5, Santiago Martín-Bravo1, Pedro Jiménez-Mejías1 1 Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain 2 Área de Botánica, Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Seville, Spain 3 University of Michigan Herbarium, Ann Arbor, MI, USA 4 Laboratorio de Florística, Departamento de Dicotiledóneas, Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima, Peru 5 Centro de Investigación de la Biodiversidad y Cambio Climático (BioCamb) e Ingeniería en Biodiversidad y Recursos Genéticos, Facultad de Ciencias de Medio Ambiente, Universidad Tecnológica Indoamérica, Quito, Ecuador Corresponding authors: Luis González-Gallego ([email protected]); Pedro Jiménez-Mejías ([email protected], [email protected]) Copyright: © Luis González-Gallego et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International – CC BY 4.0). Research Article Abstract The Huancabamba Depression in Neotropical South America, a natural barrier between the Northern and Central Andes, serves as a refuge for high levels of angiosperm diversity. However, this biodiversity remains understudied, especially in complex and species-rich genera, such as Carex L. (Cyperaceae). This genus is notably underrepresented in taxonomic and systematic research on the Neotropics. In this study, we employed an integrative systematic approach combining molecular and morphological data to elucidate the taxonomic status of several Carex populations from Ecuador and northern Peru, which exhibit morphological affinities with the sect. Porocystis Dumort. (Castanea Clade). We conducted a phylogenetic analysis using two nuclear (ITS and ETS) and one plastid (matK) DNA regions and carried out a detailed morphological comparison with Neotropical relatives within the section. Both phylogenetic and morphological results supported the systematic distinctiveness of the focal populations. As a result, we describe a new species, Carex huancabambica Gonz.Gallego & Jim.Mejías, sp. nov. and provide its taxonomic treatment. This study contributes to disentangling the biodiversity of the genus Carex in the Neotropics. Key words: Andes, Neotropics, new species, phylogenetics, Porocystis, South America, systematics, taxonomy Introduction The Neotropical Region harbours the richest plant diversity in the whole world, comprising approximately 90,000–110,000 species of seed plants, which represent around 37% of the world’s species (Antonelli and Sanmartín 2011). This region extends from central Mexico to northern Chile and central-western Argentina, covering the whole Central America, the majority of South America, the Antilles and South American Pacific Islands (Morrone 2014; Hermogenes De Mendonça and Ebach 2020). The remarkable levels of biodiversity of the Academic editor: Peter de Lange Received: 15 July 2025 Accepted: 6 September 2025 Published: 31 October 2025 Citation: González-Gallego L, BenítezBenítez C, Reznicek AA, Cano A, Oleas NH, Martín-Bravo S, Jiménez-Mejías P (2025) Carex huancabambica (Cyperaceae), a new species from the Peruvian and Ecuadorian Andes. PhytoKeys 265: 161–180. https://doi. org/10.3897/phytokeys.265.161909 PhytoKeys 265: 161–180 (2025) DOI: 10.3897/phytokeys.265.161909 162 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species Neotropics are reflected in the wide range of vegetation types, biomes and their underlying ecosystems. These include the tropical rainforests found in the Amazonian territories, the arid deserts expanding from northern Mexico, grass and tree savannahs, subtropical rainforests and subtropical dry forests, areas of Mediterranean-like vegetation along the Pacific coast and the montane forests and high-altitude grasslands of the Andes Mountain range (Antonelli and Sanmartín 2011). Within the South American Neotropics, the Andean cordilleras encompass the broadest range of biotic (e.g. interactions) and abiotic (e.g. temperature, rainfall, soil, topography) factors. This results in a great richness and diversity of flora distributed along an elevational gradient. The regionalisation of the tropical Andes comprises the Northern and Central Andes, extending approximately 35 degrees of latitude from the north of the Sierra Nevada de Santa Marta (Colombia) and the Sierra Nevada de Mérida (Venezuela) to the northernmost regions of Salta and Jujuy in Argentina (Luteyn and Churchill 2000). The limit between the northern and the central parts of the cordilleras is given by the Huancabamba Depression (see below). The distinction between these two regions arises from differences in both abiotic and biotic factors, including, for example, the tectonic style – belonging to the northern and central volcanic zones, respectively – and the uplift history, inferred through paleoelevation estimates, based on modern climatic and geological indicators (Gregory-Wodzicki 2000). These differences are reflected in the current variation of the biodiversity found in both sides of the cordilleras and help delimit the northern and central regions of the Andes Mountains (Gregory-Wodzicki 2000; Weigend 2002). The Huancabamba Depression, located in northern Peru and southern Ecuador, constitutes the lowest elevational zone (2,145 m at Abra de Porculla, Peru) in the entire Andean cordilleras and is recognised as a distinct phytogeographical region: the Amotape–Huancabamba Zone, that separates the Northern Andes from the Central Andes through the Río Chamaya and Río Marañón river systems (Berry 1982; Weigend 2002). This lower area constitutes a gap among high altitude Andean habitats and produces an important biogeographic turnover between the Northern and Central Andes. Conversely, this region serves as a convergence zone for taxa from both the Northern and Central Andes, acting as the southernmost range limit for northern taxa and the northernmost for southern taxa. The fragmented habitat and ecologically diverse ecosystems found in the Huancabamba Depression appear to have triggered speciation processes, as is reflected in the high plant species diversity and endemicity (Weigend 2002). For instance, species of Nasa Weigend (Loasaceae Juss.) occur in numbers six to eight times greater than in surrounding areas (Weigend 2002). These characteristics explain its consideration as a distinct biogeographical region and a major biodiversity hotspot, hosting approximately 318 endemic species of angiosperms (Weigend 2002). Carex L. (Cyperaceae Juss.), with over 2,000 species, is the second most diverse genus of monocots after Bulbophyllum Thouars (Orchidaceae Juss.) and ranks among the five most species-rich genera of angiosperms (POWO 2025). It has a cosmopolitan distribution, with presence across all continents, except Antarctica, though it is largely absent from lowlands in tropical latitudes (POWO 2025). While Carex species predominantly inhabit wet environments in cold-temperate zones of the Northern Hemisphere (boreo-temperate regions), 163 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species they are also found, to a lesser extent, in temperate areas of the Southern Hemisphere (Ball and Reznicek 2003; Martín-Bravo et al. 2019; Benítez-Benítez et al. 2021). In these southern regions, the genus has histori cally been underrepresented in taxonomic and systematic studies. Approximately 200 species of Carex have been described as native to South America, most of which are endemic to the continent (Morales-Alonso et al. 2024). In contrast to the extensive floristic treatments available for the genus in the Northern Hemisphere (e.g. Carex in the former USSR, Egorova (1999); Flora of North America, Ball and Reznicek (2003); Flora of China, Dai et al. (2010)), the South American species and clades have traditionally remained largely understudied, with only a few recent integrative taxonomic efforts addressing this knowledge gap (Jiménez-Mejías et al. 2020, 2021; Muñoz-Schüler et al. 2023; Morales-Alonso et al. 2024). Among the causes of this scenario are the limited accessi bility of herbaria and digitisation of collections (which hinder taxo nomic revisions or new descriptions), as well as the lack of regional taxonomic experts (Morales-Alonso et al. 2024). Within the subgenus Carex, the predominantly American Castanea Clade comprises over 60 species, some of which are pending taxonomic re-evaluation. With only 40 species sampled in molecular phylogenetic studies to date (Roalson et al. 2021), the sectional delimitation of the clade remains unclear due to significant morphological heterogeneity. Traditional classification attempts (Hermann 1974; Ball and Reznicek 2003) recognised various sections within the Castanea Clade, the majority of which have been retrieved as polyphyletic in the latest phylogenetic framework classifications (Roalson et al. 2021). Nearly half of the species of the clade are comprised within sects Longicaules Mack. ex Reznicek and Porocystis Dumort. These two sections, along with the monospecific sect. Hirtifoliae Reznicek comprising North American C. hirtifolia Mack., represent the only monophyletic groups currently recognised within the clade (Roalson et al. 2021). In North America, Mexico and Central America, Carex sect. Porocystis sensu stricto (sect. Porocystis hereafter) has been considered in Hermann’s (1974) revision of the genus in Mexico and Central America, the monographic treatment of the section in these regions by Reznicek and González-Elizondo (2001) and Flora of North America (Ball and Reznicek 2003). Species in this section are primarily native to North America, although some of them extend into the Neotropical regions of Mexico, Guatemala and South America and one species is also present in Eurasia (C. pallescens L.). They are morphologically commonly characterised by pubescent leaves and culms, as well as by mostly gynae candrous terminal spikes and utricles often pubescent, but some variation in these characters is still observed among the species comprised within the section. To date, the Neotropical members of sect. Porocystis consist of four species and three subspecies (totalling seven taxa), clearly delimited both by clear-cut diagnostic morphological characters and by largely non-overlapping distribution ranges (Reznicek and Wheeler 1993; Reznicek and González-Elizondo 2001; Table 1; Fig. 1). Most taxa are distributed in North and Central America (Mexico and Guatemala) and the knowledge of the South American representatives of this section remains restricted to two species: the Venezuelan endemic C. tovarensis, and C. boliviensis, the type subsp. boliviensis remarkably disjunct between Mexico and the Andes (Table 1; Fig. 1). These taxa typically inhabit montane to alpine wet to moist environments, mostly in open habitats. 164 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species In this study, we examined the taxonomic identity of several populations of a Carex taxon from northern South America that are morphologically assignable to sect. Porocystis. The specimens of study were collected from a number of localities in Ecuador (Provinces of Azuay, Carchi, Imbabura, Loja and Pichincha), as well as in northern Peru (Departments of Cajamarca and Piura) within the Amotape–Huancabamba Zone, immediately north of the northernmost limit of C. boliviensis in South America. Using morphological comparisons with closely-related taxa, combined with DNA-based phylogenetic analyses, we assessed whether these populations constitute a new species and determined their phylogenetic placement within the section. Accordingly, we proceed to describe it as Carex huancabambica Gonz.Gallego & Jim.Mejías. Materials and methods Molecular sampling For the phylogenetic analyses conducted in this study, we included 27 acce ssions belonging to selected taxa from the different sections included by Roalson et al. (2021) within the Castanea Clade (Suppl. material 1). As outgroup, we included C. elliottii from the Hirta Clade, a group closely related to the Castanea Clade (Roalson et al. 2021). These sequences were retrieved from previous Carex phylogenetic studies (Jiménez-Mejías et al. 2016; Martín-Bravo et al. 2019). To complete our sampling, we generated new sequence data from three populations of C. huancabambica, two specimens of C. boliviensis from Argentina and one from Peru and one specimen of C. complanata subsp. tropicalis from Guatemala (Suppl. material 1). The C. huancabambica material used for the molecular Table 1. Distribution range, habitat and altitude occupied by the Neotropical representatives of Carex sect. Porocystis. The newly described C. huancabambica is included for comparison. Data extracted from Reznicek and Wheeler (1993), and Reznicek and González-Elizondo (2001). Species Carex angustispica Reznicek & S.González Carex boliviensis Van Heurck & Müll.Arg. Carex complanata Torr. & Hook. Carex huancabambica Gonz.Gallego & Jim.Mejías Carex tovarensis Reznicek & G.A.Wheeler subsp. boliviensis subsp. occidentalis Reznicek & S.González subsp. tropicalis Reznicek & S.González Distribution range Oaxaca (SW Mexico), with isolated occurrences in Querétaro (NE Mexico) Disjunct in Mexico and the Andes, in Sierra Madre Oriental (C Mexico) and Transvolcanic Belt (S Mexico) and from N Peru to N Argentina Sierra Madre Occidental, from S Chihuahua to Guerrero (NW to SW Mexico) CentralAmerican Cordillera, in Chiapas (SE Mexico) and Guatemala N Andes, in N Peru and Ecuador, in the neighbouring regions around the Huancabamba Depression and north of it Coastal range of northern Venezuela Habitat Subalpine open mesic habitats, including high-altitude grasslands, and open scrublands and pine forest Subalpine to alpine moist and mesic open habitats, including grasslands, meadows and open scrublands Montane to subalpine moist habitats in meadows and open pine and oak forest Montane moist habitats in open scrublands and pine – oak forests Montane to subalpine moist habitats, in meadows, grasslands and open forests Montane open moist habitats, including high-altitude grasslands, and open scrublands Altitude (m) 2,800–3,000 2,700–4,100 (2,000–) 2,500– 3,200 1,600–2,800 2,900–3,900 2,000–2,300 165 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species sampling were collected by the last two authors of this paper in two fieldwork campaigns in Peru and Ecuador. The vouchers were deposited at HUTI, UPOS and USM herbaria. Herbarium acronyms follow Thiers (2025). Molecular phylogenetic study Phylogenetic relationships were reconstructed using three DNA barcoding regions commonly used in Carex phylogenetics at subgeneric and sectional levels: the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS), Figure 1. Distribution map representing the Neotropical species of Carex sect. Porocystis. Occurrence data (Suppl. material 2; Sanz-Arnal et al. 2025a, b) includes the studied specimens of Carex huancabambica sp. nov. (field collections and herbaria specimens examined, deposited at HUTI, QCA, QCNE, UPOS and USM). 166 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species the nrDNA external transcribed spacer (ETS) and the chloroplast DNA (cpDNA) maturase K (matK) gene. DNA extraction and sequence amplification followed Benítez-Benítez et al. (2021). All PCR products were sequenced externally by Macrogen (Madrid, Spain). Sequence chromatograms for each sample and marker were manually reviewed and processed using Geneious v.11.0.1 (Biomatters Ltd., Auckland, New Zealand; https://www.geneious.com). For each DNA region, an aligned matrix was constructed that included both the newly-obtained sequences and those retrieved from previous studies on Carex (Jiménez-Mejías et al. 2016; Martín-Bravo et al. 2019). First, the alignments were performed automatically using Muscle (Edgar 2004) and subsequently reviewed and edited manually. Informative insertions and deletions (indels) were manually coded in each matrix as additional binary characters. To determine the best-fit model of nucleotide substitution for each DNA region, we used jModelTest 2 2.1.10 v.20160303 (Darriba et al. 2012) following the Akaike Information Criterion (AIC; Nylander et al. (2004)). A singleton matrix was constructed selecting, for each taxon, the sequence with the least missing data per DNA region, resulting in a singleton dataset comprising 31 accessions. However, for C. boliviensis and C. huancabambica, multiple sequences were sampled and included in the matrix to maximise the phylogenetic resolution in the involved branches. In total, 24 species were included in our phylogeny of the Castanea Clade, plus the outgroup sequence. Phylogenetic reconstructions were performed using Bayesian Inference (BI) and Maximum Likelihood (ML) methods. Bayesian analyses were performed using MrBayes 3.2.7a (Ronquist et al. 2012), employing four simultaneous Markov Chain Monte Carlo chains run for five million generations, with trees sampled every 100 generations to estimate the posterior probability distribution. ML analyses were conducted using RAxML v.8.2.10 (Stamatakis 2014), with 100 bootstrap replicates. All analyses were run in CIPRES Science Gateway (Miller et al. 2015). Bayesian trees were visualised using FigTree v.1.4.4 (Rambaut 2008) and ML trees by using TreeGraph 2.15.0–887 beta (Stöver and Müller 2010). Clade support was considered strong at probability (PP) values greater than 0.8 and bootstrap support (BS) values greater than 60%. Morphological study We examined representative material from the Neotropical members of Carex sect. Porocystis that were recovered in our phylogenies as closely related to C. huancabambica (see Results: Molecular and phylogenetic study). This included the collected specimens of C. huancabambica from Peru and Ecuador (Suppl. material 2), as well as herbarium specimens from the newly-described species and herbarium specimens of C. boliviensis (Suppl. material 2) and of C. angustispica (Suppl. material 2). Material from the sampled populations of C. huancabambica (Suppl. material 2) was carefully examined for its description and compared with all morphologically close and phylogenetically related Neotropical species of sect. Porocystis (see Results: Molecular and phylogenetic study). The selection of diagnostic characters and morphological comparisons among species were based on both specialised literature on sect. Porocystis (Reznicek and González-Elizondo 2001) and herbarium specimens examined 167 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species (Suppl. material 2). Measurements under 1 cm were taken using a binocular micrometer (Nikon SMZ645), except for macromorphological characters that were measured with a standard 30 cm ruler. Results Molecular and phylogenetic study The topology of the combined tree mostly agrees with that obtained from the nrDNA and cpDNA individual trees. For greater clarity, we describe the topology of the concatenated tree (Fig. 2). Our phylogenetic reconstruction shows a well-supported monophyletic group (PP = 1, BS < 60%), which is structured into two major subclades. The first subclade, which is moderately supported (PP < 0.8, BS = 70%), includes C. californica, C. pallescens and C. torreyi. The second subclade is strongly supported (PP = 1, BS = 100%) and corresponds to the rest of the included taxa of the Castanea Clade. Carex caeligena and C. anisostachys (PP = 1, BS = 66%) form a sister group to a larger, well-supported subclade (PP = 0.97, BS < 60%) that includes the focal Neotropical taxa of this study. In this subclade in particular, C. huancabambica yielded a supported monophyletic group with C. boliviensis and C. angustispica. The tree topology supported the recognition of C. huancabambica as a distinct species, recovered in a well-supported clade (PP = 1; BS = 92%). The only included sample of the Mexican C. angustispica was recovered as unresolved, whereas both Mexican and South American samples of the two C. boliviensis subspecies were recovered intermingled forming a monophyletic group (PP = 0.99, BS < 60%). The other Neotropical representatives of the group, C. complanata subsp. tropicalis and C. tovarensis, were excluded from that clade. Both samples of Carex complanata (subsp. complanata and subsp. tropicalis) formed a well-supported clade (PP = 1; BS = 76%). Carex tovarensis, on the other hand, was recovered in a well-supported clade with North American C. swanii (PP = 1; BS = 68%). Morphological study The detailed morphological examination and comparison of the diagnostic characters of C. huancabambica (Figs 3, 5A–J), C. boliviensis (Figs 4A, 5K–O) and C. angustispica (Figs 4B, 5P–T) revealed notable morphological affinities among the three taxa, but also clear differences in both qualitative and quantitative characters (Table 2). Discussion Sources of phylogenetic and morphological evidence support the systematic distinctiveness of the studied Peruvian and Ecuadorian sect. Porocystis populations, validating the recognition of C. huancabambica as a new species (Figs 2, 3, 5A–J). The greatest morphological affinities of these populations are observed with sect. Porocystis representatives C. boliviensis and C. angustispica according to the keys available in Reznicek and González-Elizondo (2001). However, clear-cut morphological differences between these taxa are also depicted (shape and indumentum of utricle and shape of achene; see Table 2). The distinctiveness is further supported by 168 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species variation in geographic distribution and elevation (Table 1; Fig. 1). The molecular phylogeny also supported C. huancabambica as a different species from C. boliviensis and C. angustispica (Fig. 2). Accordingly, we proceed to formally describe C. huancabambica. This discovery contributes to the taxonomic knowledge of the genus Carex in South America, enhancing our understanding of the understudied Neotropical representatives of the Castanea Clade and of sect. Porocystis, in particular. Figure 2. Bayesian phylogenetic tree obtained from the concatenation of nrDNA (ITS and ETS) and cpDNA (matK) sequences of species of the Castanea Clade including one tip per taxon and multiple tips per taxon for the focal populations, highlighted in grey. Both BI posterior probabilities (PP > 0.8) and ML bootstrap (BS > 60%) values are given above and below branches, respectively, for bold thick branches. The placement of Carex huancabambica sp. nov. is highlighted in red colour. Tip labels include the geographical origin of the specimen using TDWG level 3 region abbreviations (“botanical countries”; Brummitt (2001)) and the ID-specification of the specimen or voucher (Suppl. material 1). 68 92 69 76 68 100 1 66 70 Castanea Clade Focus group 0.004 C. aff. pinophila | MXE | spm00000284 C. angustispica | MXS | spm00000262 C. boliviensis subsp. boliviensis | PER1 | 136SMB21 C. complanata subsp. tropicalis | MXT | González10469 C. huancabambica | PER1 | 37PERPJM21 C. complanata subsp. complanata | TEX | spm00000782 C. tovarensis | VEN | Baruch28 C. californica | CAL | spm00001685 C. hirtifolia | QUE | spm00001475 C. roanensis | NCA | spm00001224 C. debilis | OKL | spm00000863 C. boliviensis subsp. boliviensis | MXS | González10532 C. huancabambica | PER2 | 73PERPJM21 C. aestivalis | PEN | spm00000681 C. torreyi | COL | spm00001708 C. swanii | ARK | spm00001304 C. venusta | MSI | spm00001372 C. boliviensis subsp. occidentalis | MXE | spm00000250 C. formosa | ILL | spm00001732 C. caeligena | MXE | spm00000264 C. anisostachys | MXT | spm00000258 C. boliviensis subsp. occidentalis | MXE | Reznicek12260 C. caroliniana | ALA | spm00000815 C. oxylepis | KTY | spm00001137 C. boliviensis subsp. boliviensis | AGE | 50GERP15 C. tenax | LOU | spm00001308 C. elliottii | FLA | spm00001916 C. pallescens | BRC | spm00002008 C. gynodynama | CAL | spm00001688 C. boliviensis subsp. boliviensis | AGW | 68GERP15 C. whitneyi | CAL | spm00001352 C. boliviensis subsp. boliviensis | MXC | spm00000255 C. arctata | WIS | spm00000731 C. huancabambica | ECU | 21ECU-AMA22 1 1 0.97 1 1 0.99 0.80 0.99 0.86 0.97 1 0.96 169 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species All nomenclatural and taxonomic decisions in this study follow the rules and recommendations of the International Code of Nomenclature for algae, fungi and plants (ICN; Turland et al. (2018)). Taxonomic treatment Carex huancabambica Gonz.Gallego & Jim.Mejías, sp. nov. urn:lsid:ipni.org:names:77369003-1 Figs 3, 5A–J Diagnosis. This species is superficially similar to C. boliviensis, from which it primarily differs by stiff short stems (wiry and flexuous in C. boliviensis), as well as by the utricle shape, broadly elliptical (ovate to narrowly elliptical in C. boliviensis). From the also closely-related C. angustispica, C. huancabambica differs in its smaller size, with culms from < 0.50 (subacaulescent) to 25 cm ((3–) Table 2. Comparison of the main diagnostic morphological characters among C. huancabambica, C. boliviensis and C. angustispica. Measurements for the first two were obtained following the procedures described in the Materials and Methods section, while data for C. angustispica were sourced from Reznicek and González-Elizondo (2001). C. huancabambica C. boliviensis C. angustispica subsp. boliviensis subsp. occidentalis Habit Erect, stiff culms Decumbent or prostrate, wiry and flexuous culms Robust, with erect culms, somewhat wiry and flexuous, arching or ± decumbent Erect, stiff culms Fertile culm length (cm) < 0.50 (subacaulescent) to 25 3–64 35–87 (3–) 10–65 Leaf length (cm) Up to 11 3.5–25 (2.5–) 5–28 Leaf indumentum Glabrous to ± pubescent on abaxial surface, especially proximally and along the margins and veins Pubescent basally or almost glabrous Basally pilose Inflorescence length (mm) 14–32 11–26 (–3.2) (1–) 25–61 8–45 Lateral spikes Pistillate, rarely staminate Pistillate or gynaecandrous Pistillate Terminal spike length (mm) 10.0–15.5 (6–) 8–17 (9–) 15–30 ca. 14 Spikes number (1–) 3–4 (1–) 2–4 2–4 (–5) Glume length (mm) 1.7–2.5 1.8–2.3 1.8–3.4 1.6–2.4 (–2.6) Glume width (mm) 1.0–1.5 1.1–2 (–2.2) 1.3–1.7 Glume apex Obtuse, or acute to nearly acuminate Obtuse to acute Obtuse to acuminate Utricle length (mm) 2.0–2.8 2.2–3.2 (–3.4) 3.0–4.1 (–4.6) 2.1–2.8 Utricle width (mm) 1.0–1.4 1.4–1.75 1.2–1.5 Utricle shape Broadly elliptical to elliptical– obovate Narrowly elliptical to ovate Ovoid to obovoid Utricle indumentum Glabrous or loosely pilose on all its surface Glabrous Glabrous Achene length (mm) 1.5–1.9 1.6–2.2 2.0–2.6 1.4–1.8 Achene width (mm) 0.9–1.3 1.1–1.5 1.1–1.3 Achene shape Broadly elliptical to suborbicular Broadly elliptical to suborbicular Narrowly obovate to narrowly elliptical 176 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species Ethical statement No ethical statement was reported. Use of AI No use of AI was reported. Funding This study has been made possible by funding received by the Spanish Research Agency of the Ministry of Science and Innovation (Project DANZ, Ref. PID2020-113897GB-I00 to PJ-M and SM-B and Project CONSO, Ref. PID2023-147332NB-I00 to SM-B and PJ-M, and Ramón y Cajal postdoctoral funds to PJ-M). We acknowledge Universidad Pablo de Olavide for financial support granted to LG-G (B2 Grant for Research or Tutored Knowledge Transfer, VI Plan Propio de Investigación y Transferencia 2023–2026, Ref. PPI2403, 18.00.00.0005-541A-647). CB-B was supported by a Juan de la Cierva Postdoctoral Fellowship (JDC2022-048955-I) funded by the Ministry of Science, Innovation and Universities (MICIU/AEI/10.13039/501100011033) and European Union NextGenerationEU/PRTR. Author contributions LG-G carried out the laboratory work, performed the analyses and drafted the manuscript. CB-B performed phylogenetic analyses and drafted the manuscript. AR, AC, NO drafted the manuscript. SM-B collected plant material and drafted the manuscript. PJ-M conceived the idea, collected plant material and drafted the manuscript. All authors contributed to the writing of the final version. Author ORCIDs Luis González-Gallego https://orcid.org/0009-0006-1643-7292 Carmen Benítez-Benítez https://orcid.org/0000-0003-4956-0343 Anton A. Reznicek https://orcid.org/0000-0002-9467-6225 Asunción Cano https://orcid.org/0000-0002-5759-4650 Nora H. Oleas https://orcid.org/0000-0002-1948-4119 Santiago Martín-Bravo https://orcid.org/0000-0003-0626-0770 Pedro Jiménez-Mejías https://orcid.org/0000-0003-2815-4477 Data availability All of the data that support the findings of this study are available in the main text or Supplementary Information. References Antonelli A, Sanmartín I (2011) Why are there so many plant species in the Neotropics? 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Botanical Review 68(1): 38–54. https://doi.org/10.1663/0006 -8101(2002)068[0038:OOTBOT]2.0.CO;2 Supplementary material 1 List of sequenced specimens used for the phylogeny Authors: Luis González-Gallego, Carmen Benítez-Benítez, Anton A. Reznicek, Asunción Cano, Nora H. Oleas, Santiago Martín-Bravo, Pedro Jiménez-Mejías Data type: xlsx Explanation note: List of sequenced specimens used for the phylogeny (Fig. 2) with their accession numbers included, including the newly-sequenced material of the taxa of study, highlighted in bold and the previously published sequences (Jiménez-Mejías et al. 2016; Martín-Bravo et al. 2019). Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/phytokeys.265.161909.suppl1 180 PhytoKeys 265: 161–180 (2025), DOI: 10.3897/phytokeys.265.161909 Luis González-Gallego et al.: Carex huancabambica, a new Andean species Supplementary material 2 List of studied material used for the morphological part of the present study Authors: Luis González-Gallego, Carmen Benítez-Benítez, Anton A. Reznicek, Asunción Cano, Nora H. Oleas, Santiago Martín-Bravo, Pedro Jiménez-Mejías Data type: xlsx Explanation note: List of studied material used for the morphological part of the present study (Figs 3–5), including all the specimens with coordinate data (Sanz-Arnal et al. 2025a, b) used to build the distribution map of the Neotropical species of sect. Porocystis (Fig. 1). Information of taxon, authors, country (TDWG level 3 region abbreviations (“botanical countries”; Brummitt (2001)), locality of collection, herbarium and voucher number, collector and code of collector is included. Examined specimens are marked with !. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/phytokeys.265.161909.suppl2