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Reticulate evolution (RE), involving hybridization and related processes, generates network-like rather than strictly bifurcating relationships among lineages and can obscure phylogenetic relationships. Detecting ancient hybridization is particularly challenging, as genomic signals may erode over time. The Malvatheca clade (Malvaceae), marked by multiple paleopolyploidy events since it’s estimated origin 66 my, offers a useful model for examining RE. Its three subfamilies—Bombacoideae (with high chromosome numbers, mostly trees), Malvoideae (lower chromosome numbers, mostly herbs), and the recently described Matisioideae—show unresolved relationships, with several taxa of uncertain placement. We conducted a phylogenomic analysis of 69 Malvatheca species via complete plastomes, 35S rDNA cistrons, nuclear low copy genes and comparative repeatome data. Most of the datasets consistently resolved four clades: (I) Bombacoideae, (II) Malvoideae, (III) Matisioideae, and (IV) a heterogeneous assemblage including representatives of Malvoideae, Matisioideae and several incertae sedis taxa. Chromosome numbers were negatively correlated with repeatome diversity: Bombacoideae presented higher counts but lower repeat diversity, possibly reflecting slower repeat evolution associated with woody growth forms. In contrast, clades III and IV showed marked heterogeneity in both chromosome number and repeat composition, which is consistent with a reticulate origin. Overall, our results show evidence of ancient hybridization and polyploidy in shaping Malvatheca evolution. These results highlight that reticulation and genome dynamics, rather than taxonomic boundaries alone, are central to understanding the diversification of Malvatheca.

Based on observations made during botanical surveys in the southern sub-Andean of Bolivia, analysis of collected material, review of herbarium material and online databases, we determined that the Ceiba populations of the xeric Bolivian-Tucuman forests, previously identified as Ceiba chodatii, correspond to a new species. Given that the morphological, ecological and distributional characteristics differ from those observed in populations of C. chodatii, we propose Ceiba guarani sp. nov. Our field observations and distribution data from the revised specimens indicate that C. chodatii is naturally restricted to the Chaco plains and a strip of the southern Subandean foothills, whereas Ceiba guarani is distributed mainly in the Subandean ranges. A partir de observaciones hechas durante prospecciones botánicas al Subandino sur de Bolivia, análisis de material colectado, revisión de material de herbarios y bases de datos online, determinamos que las poblaciones de Ceiba de los bosques xéricos Boliviano-Tucumano, previamente identificadas como Ceiba chodatii, corresponden a una nueva especie. Dado que las características morfológicas, ecológicas y de distribución difieren de lo observado en las poblaciones de C. chodatii, se propone Ceiba guarani sp. nov. Nuestras observaciones de campo y los datos de distribución de los especímenes revisados, indican que C. chodatii está naturalmente restringida a las llanuras chaqueñas, y una franja del piedemonte del Subandino sur, en tanto que Ceiba guaraní se distribuye principalmente en las serranías del Subandino.

A new species of Malvaceae, Spirotheca zapotillana , is described from the Equatorial Pacific region of South America. The species occurs in seasonally dry tropical forests of El Oro and Loja provinces in southern Ecuador. It is characterized by a strictly tree-like habit, elliptical leaflets with acute apices, glandular floral receptacles, glabrous styles, oblong capsules, and reniform seeds. A morphological description of the new species is provided, along with data on its habitat and distribution, an assessment of its conservation status, and an updated key for the genus.

Bird pollination in Asia is regarded as an uncommon phenomenon and, therefore, only a few investigations on mating pattern and paternity in fruits of Asian bird-pollinated plants have been conducted. Here, we examined spatial genetic structure, pollen dispersal, and multiple paternity in a natural population of Bombax ceiba ( B. ceiba ) (Malvaceae) in Hainan Island, South China, using simple sequence repeat (SSR) markers. A low genetic diversity ( H e = 0.351 ± 0.0341 and 0.389 ± 0.043, respectively, for adults and offspring) and bottleneck effects were observed. Genetic kinship was significant within 400 m or in 1,800–3,800 m. Both the mating pattern and paternity analysis confirmed obligate xenogamy and a low multiple paternity in B. ceiba . There was a strongly negative relationship between the frequency of matings and the distance between mating pairs. The average pollen dispersal distance was 202.89 ± 41.01 m (mean ± SE) and the farthest distance of > 1 km was recorded. Realized mating events showed an extremely leptokurtic distribution within 1,200 m, suggesting that the pollen dispersal distance was consistent with the optimal foraging theory of generalist birds such as Zosterops spp. and Pycnonotus spp. Paternity per tree ranged from two to six and the average effective number of pollen donors per maternal plant was 3.773, suggesting a low level of paternity diversity as compared to other bird-pollinated plants. We concluded that optimal foraging behavior by generalist birds could explain the leptokurtic pollen dispersal distribution and predominantly near-neighbor matings in B. ceiba . The limited pollen dispersal distance and low multiple paternity were consistent with low fruit setting rate (3.27 ± 0.93%) in this self-incompatible tree, which was caused mainly by the restricted flight distance of birds and human disturbances. Low genetic diversity and significant spatial genetic structure might have largely resulted from logging and human collection of fruits.

A taxonomic review of the three genera of Malvaceae subfamily Bombacoideae growing in Argentina is presented. Ceiba is a Neotropical genus, represented by 3 species in Argentina, Eriotheca is a genus from tropical South America, with 1 species in Argentina, and Pseudobombax is a Neotropical genus, represented by 1 species in the territory. A key to the species of each of the genera, complete descriptions of the taxa, a distribution map, illustrations, photographs and a list of examined material are provided. Five lectotypes are designated for Bombax marginatum f. arborea (=Pseudobombax argentinum), Ceiba glaziovii f. transiens (=C. pubiflora), Ceiba pubiflora f. praecox (=C. pubiflora), Chorisia speciosa var. paraguariensis (=C. speciosa), and Tartagalia rubra (=Eriotheca roseorum), and a second step lectotype is established for Eriodendron pubiflorum (≡ Ceiba pubiflora); in turn, Ceiba guarani is proposed as a new synonym for C. chodatii. Se presenta una revisión taxonómica de los tres géneros de Malvaceae subfamilia Bombacoideae que crecen en Argentina. Ceiba es un género neotropical, representado por 3 especies en Argentina, Eriotheca es un género de Sudamérica tropical, con 1 especie en Argentina y Pseudobombax es un género neotropical, representado por una especie en el territorio. Se aporta una clave para las especies de cada uno de los géneros, descripciones completas de los taxones, mapas de distribución, ilustraciones, fotografías y una lista de material examinado. Se designan 5 lectotipos, para Bombax marginatum f. arborea (=Pseudobombax argentinum), Ceiba glaziovii f. transiens (=C. pubiflora), Ceiba pubiflora f. praecox (=C. pubiflora), Chorisia speciosa var. paraguariensis (=C. speciosa) y Tartagalia rubra (=Eriotheca roseorum), y se establece un segundo paso de lectotipificación para Eriodendron pubiflorum (≡ Ceiba pubiflora); a su vez se propone Ceiba guarani como nuevo sinónimo para C. chodatii.

Plants belonging to the subfamily Bombacoideae (family Malvaceae) consist of about 304 species, many of them having high economical and medicinal properties. In the past, this plant group was put under Bombacaceae; however, modern molecular and phytochemical findings supported the group as a subfamily of Malvaceae. A detailed search on the number of publications related to the Bombacoideae subfamily was carried out in databases like PubMed and Science Direct using various keywords. Most of the plants in the group are perennial tall trees usually with swollen tree trunks, brightly colored flowers, and large branches. Various plant parts ranging from leaves to seeds to stems of several species are also used as food and fibers in many countries. Members of Bombacoides are used as ornamentals and economic utilities, various plants are used in traditional medication systems for their anti-inflammatory, astringent, stimulant, antipyretic, microbial, analgesic, and diuretic effects. Several phytochemicals, both polar and non-polar compounds, have been detected in this plant group supporting evidence of their medicinal and nutritional uses. The present review provides comprehensive taxonomic, ethno-pharmacological, economic, food and phytochemical properties of the subfamily Bombacoideae.

The present study updates the taxonomy of Quararibea in the Atlantic Forest of Southeast Brazil. After 130 yr, Quararibea penduliflora has once again been reported in Rio de Janeiro State. A new combination is proposed, Q. angustifolia, and a new species, Q. similis, is described. Descriptions, species identification keys, illustrations, and a new analysis of the morphology of domatia, aimed at using its diagnostic potential to circumscribe the species studied here, are provided.

• Premise of the study: Whole genome duplication (WGD) and specific polyploidy events marked turning points for angiosperm genome structure and evolution. Therefore, cytogenetic studies of polyploidy-prone groups such as the tropical Malvaceae and plant formations such as as the Brazilian Cerrado have gained further importance. We present new chromosome counts for Cerrado Bombacoideae and revised chromosome numbers for the Malvaceae s.l., compare these between subfamilies, and relate them to phylogenetic signal.• Methods: We studied the chromosome number of Eriotheca candolleana, E. gracilipes, E. pubescens, Pachira glabra, Pseudobombax longiflorum, and P. tomentosum. We also compared Eriotheca species ploidy levels using flow cytometry. We compiled chromosome numbers for 557 species of Malvaceae s.l., including 37 Bombacoideae species. We included this information in a phylogenetic reconstruction based on chloroplast matK-trnK DNA to evaluate chromosome evolution of the Malvaceae s.l. and the Bombacoideae in particular.• Key results: The Cerrado Bombacoideae presented consistently high chromosome numbers. Numbers for Eriotheca species were among the highest and varied among populations. Flow cytometry analyses showed similar 1Cx DNA for all cytotypes and indicated neopolyploidy. Chromosome numbers differed between subfamilies, with the lowest numbers in the Malvoideae and Byttnerioideae and the highest in Tilioideae. Chromosome numbers had significant phylogenetic signal for Bombacoideae but not for Malvoideae or Malvaceae s.l.• Conclusions: Clearly distinct chromosome numbers allied to monophyly provide some support for a circumscription of the Bombacoideae and distinction within the Malvaceae. The phylogenetic signal for chromosome number supports the idea of an ancient WGD and further neopolyploidy events as important evolutionary trends for the Bombacoideae.

Molecular and morphological data have shown that Bombacoideae and Malvoideae together form a well-supported Malvatheca clade. Phylogenetic relationships in Bombacoideae have been studied, but some genera in Bombax s. l. have not been adequately sampled for sufficiently variable molecular markers. The relationships of Eriotheca, for example, have yet to be resolved. Here, nuclear (ITS) and chloroplast (trnL-F and matK) sequence data from 50 exemplars of Bombacoideae and seven additional taxa from other genera of Malvatheca were used to test monophyly of Eriotheca and its relationships with related genera of Bombax s. l. Parsimony and Bayesian analyses of individual and combined sequence data suggest that Eriotheca is not monophyletic as currently circumscribed but forms a paraphyletic grade containing Pachira s. l. The newly discovered Eriotheca + Pachira clade has a probable synapomorphy of striate seeds. In addition, two other moderately supported clades emerged within the core Bombacoideae: Pseudobombax + Ceiba s. l. and Bombax + Spirotheca + Pachira quinata. These three clades, and the African Rhodognaphalon together constitute the major clade of core Bombacoideae, whereas Adansonia appears to be more closely related to Catostemma, Scleronema, and Cavanillesia. The phylogenetic results imply three independent migrations from the New to Old World and homoplasy in staminal morphology.

Ceiba, is a large tree used for ornamental landscaping in tropical regions of the world. It is found in tropical areas, including Mexico, Central America, South America, the Caribbean, West Africa, and Southeast Asia. The present work communicates the detailed pollen morphology of four Ceiba species growing in India including one hybrid, C. speciosa (A.St.-Hil.) Ravenna, C. insignis (Kunth) P. E. Gibbs & Semir, C. x insignis (cross between C. insignis and C. speciosa) and C. pentandra (L.) Gaertn., using Field Emission Scanning Electron Microscope (FESEM), Confocal Laser Scanning Microscope (CLSM) and Light Microscope (LM) to highlight the taxonomic characterization of these species and document finer morphological details to correlate them with other Ceiba spp., growing around the world. Pollen grain is 4-5-colporate, brevicolpate; sub-oblate to prolate-spheroidal to sub-prolate; sexine reticulate (muri provided with scattered spinuloid excrescences, lumina reticolumellate) and mostly thicker than nexine. The multivariate principal component analysis (PCA) was applied on Ceiba and Bombax ceiba to numerical data obtained from pollen morphometry which clearly revealed a significant variation between different genus and species. A pollen key, based on these micromorphological data (especially pollen aperture and size of muri), is also presented for the Ceiba and B. ceiba. The study provides an analogue for precise identification of Ceiba pollen grains recovered in Quaternary and pre-Quaternary sedimentary deposits in India and other tropical and subtropical regions of the world. Besides, pollen preservation, evolutionary trend and palaeoecology are the other important implications of this study.