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Genome size variation is a crucial aspect of plant evolution, influenced by a complex interplay of factors. Repetitive elements, which are fundamental components of genomic architecture, often play a role in genome expansion by selectively amplifying specific repeat motifs. This study focuses on Amomum , a genus in the ginger family (Zingiberaceae), known for its 4.4-fold variation in genome size. Using a robust methodology involving PhyloNet reconstruction, RepeatExplorer clustering, and repeat similarity-based phylogenetic network construction, we investigated the repeatome composition, analyzed repeat dynamics, and identified potential hybridization events within the genus. Our analysis confirmed the presence of four major infrageneric clades (A–D) within Amomum , with clades A–C exclusively comprising diploid species (2n = 48) and clade D encompassing both diploid and tetraploid species (2n = 48 and 96). We observed an increase in the repeat content within the genus, ranging from 84% to 89%, compared to outgroup species with 75% of the repeatome. The SIRE lineage of the Ty1-Copia repeat superfamily was prevalent in most analyzed ingroup genomes. We identified significant difference in repeatome structure between the basal Amomum clades (A, B, C) and the most diverged clade D. Our investigation revealed evidence of ancient hybridization events within Amomum , coinciding with a substantial proliferation of multiple repeat groups. This finding supports the hypothesis that ancient hybridization is a driving force in the genomic evolution of Amomum . Furthermore, we contextualize our findings within the broader context of genome size variations and repeatome dynamics observed across major monocot lineages. This study enhances our understanding of evolutionary processes within monocots by highlighting the crucial roles of repetitive elements in shaping genome size and suggesting the mechanisms that drive these changes.

Pimpinella saxifraga subsp. rupestris (Apiaceae) grows in a glacial cirque (Karkonosze Mountains, Sudetes, Poland) on a basalt substrate. Specimens of this species were first collected and described at the end of the 19 th century, and their taxonomic distinctiveness and endemic status were determined by Weide in 1962. The typification of the name Pimpinella saxifraga subsp. rupestris is discussed. The protologue of the name and the diagnostic phrase are evaluated based on herbarium specimen. The lectotype is designated. The paper also presents diagnostic morphological features of this and a closely related species Pimpinella saxifraga subsp. saxifraga.

In this paper we provide a thorough overview of past attempts at infrageneric classification of the genus Curcuma (Zingiberaceae). As the recent results of phylogenetic analysis of the genus confirmed that previous infrageneric classifications are not tenable, we provide a revised circumscription of Curcuma with an outline of new infrageneric classification into three subgenera, C. subg. Curcuma, C. subg. Ecomatae and C. subg. Hitcheniopsis including lists of species to be included in each subgenus. Three previously recognized genera, Laosanthus, Smithatris and Stahlianthus, are sunk to Curcuma and two species previously recognized in the genus Hitchenia, H. caulina and H. glauca, are transferred/re-recognized to Curcuma. The previously proposed transfers of the monospecific genus Paracautleya, Hedychium scaposum (Kaempferia scaposa, Monolophus scaposus) and Kaempferia candida, to Curcuma are also confirmed. All connected nomenclatural innovations, corrections and outstanding typifications, inclusive those of infrageneric names, are effected in this paper. A list of excluded names originally described as members of Curcuma, but now accepted as members of other genera is also included.

BACKGROUND AND AIMS: Genome size and chromosome numbers are important cytological characters that significantly influence various organismal traits. However, geographical representation of these data is seriously unbalanced, with tropical and subtropical regions being largely neglected. In the present study, an investigation was made of chromosomal and genome size variation in the majority of Curcuma species from the Indian subcontinent, and an assessment was made of the value of these data for taxonomic purposes. METHODS: Genome size of 161 homogeneously cultivated plant samples classified into 51 taxonomic entities was determined by propidium iodide flow cytometry. Chromosome numbers were counted in actively growing root tips using conventional rapid squash techniques. KEY RESULTS: Six different chromosome counts (2n = 22, 42, 63, >70, 77 and 105) were found, the last two representing new generic records. The 2C-values varied from 1·66 pg in C. vamana to 4·76 pg in C. oligantha, representing a 2·87-fold range. Three groups of taxa with significantly different homoploid genome sizes (Cx-values) and distinct geographical distribution were identified. Five species exhibited intraspecific variation in nuclear DNA content, reaching up to 15·1 % in cultivated C. longa. Chromosome counts and genome sizes of three Curcuma-like species (Hitchenia caulina, Kaempferia scaposa and Paracautleya bhatii) corresponded well with typical hexaploid (2n = 6x = 42) Curcuma spp. CONCLUSIONS: The basic chromosome number in the majority of Indian taxa (belonging to subgenus Curcuma) is x = 7; published counts correspond to 6x, 9x, 11x, 12x and 15x ploidy levels. Only a few species-specific C-values were found, but karyological and/or flow cytometric data may support taxonomic decisions in some species alliances with morphological similarities. Close evolutionary relationships among some cytotypes are suggested based on the similarity in homoploid genome sizes and geographical grouping. A new species combination, Curcuma scaposa (Nimmo) Škorničk. & M. Sabu, comb. nov., is proposed.

Curcuma comprises 120 species that occur throughout tropical and subtropical Asia. The taxonomy of the genus is haunted by polyploid speciation and homoploid hybridization, making it the most challenging genus in Zingibereae (Zingiberaceae). Curcuma is best known for turmeric (C. longa), but numerous species are extensively used as medicinal plants, ornamentals, and sources of starch, among many other uses. The delimitation of the genus has been a matter of dispute since its establishment by Linnaeus (1753), and further conflict has arisen from recent molecular and morphological studies suggesting either paraphyly of Curcuma or the necessity to broaden the genus to include four small genera (Laosanthus, Paracautleya, Stahlianthus, Smithatris) as well as several species currently placed in Kaempferia and Hitchenia. All previous infrageneric classifications were based on limited material that did not include species from the Indochinese floristic region, and these classifications are unable to unequivocally accommodate all currently known members of the genus. To test the monophyly and delimitation of Curcuma and to gain more insight into infrageneric relationships, three plastid regions (trnL-trnF, psbA-trnH, matK) and the internal transcribed spacer (ITS) of nuclear ribosomal DNA were sequenced. Fifty Curcuma species covering the morphological and geographic variation of the genus and 12 Curcuma-like species currently or previously treated as members of other genera were included in this study. In addition, four Zingibereae and three other Zingiberaceae species were used as outgroups. The results of maximum parsimony and Bayesian analyses clearly support a broad generic boundary for Curcuma, with inclusion of Laosanthus, Paracautleya, Stahlianthus, Smithatris and some species of Kaempferia and Hitchenia (K. scaposa, K. candida, H. caulina, H. glauca). Four main groups in Curcuma s.l. were detected, and their importance for classification at the subgenus level is discussed. A new infrageneric classification is proposed here with a formal description of a new subgenus. Cloning uncovered a broad range of variation of ITS sequences within individuals, particularly in the terminal 'Curcuma' group containing representatives of the nominal subgenus Curcuma. This 'intra-individual ITS polymorphism' increases with ploidy level and is coupled with preferred vegetative reproduction. Additional studies are needed to further uncover highly complex relationships in this subgenus.

Pimpinellasaxifragasubsp.rupestris (Apiaceae) grows in a glacial cirque (Karkonosze Mountains, Sudetes, Poland) on a basalt substrate. Specimens of this species were first collected and described at the end of the 19 century, and their taxonomic distinctiveness and endemic status were determined by Weide in 1962. The typification of the name Pimpinellasaxifragasubsp.rupestris is discussed. The protologue of the name and the diagnostic phrase are evaluated based on herbarium specimen. The lectotype is designated. The paper also presents diagnostic morphological features of this and a closely related species Pimpinellasaxifragasubsp.saxifraga.

Abstract The abundance of apomixis in tropical plant genera is poorly understood, and this affects the understanding of speciation and evolution. Hanguanaceae is a tropical monogeneric, dioecious plant family. All but two species are solitary herbs with no capability to spread vegetatively. Viable seeds are often produced when males have not been observed. Our aim was to investigate the presence of apomixis in Hanguana. We used reduced representation genomics to study phylogenetics and genetic variability in all populations of Hanguana in Singapore. We measured genome sizes and estimated ploidy levels in 10 species. Almost all taxa tested were genetically uniform (uniclonal) regardless of the extent of their distribution. The distribution of single clones over distinct localities supports our hypothesis of apomictic reproduction. Only one sexually reproducing native species was detected. Triploid and pentaploid states support our hypothesis that the type of apomixis in Hanguana is gametophytic. Population genomics tools offer a quick and cost-effective way of detecting excess clonality and thereby inferring apomixis. In the case of Hanguana, the presence of male plants is a strong indicator of sexual reproduction, whereas genome triplication is indicative of apomictic reproduction. We used reduced representation genomics to observe population diversity in the dioecious herb genus Hanguana in Singapore. Our results suggest that most of the studied species reproduce exclusively via apomictic seeds, and form populations that are composed of single, widely distributed clones. This explains a lack of records of male plants in the area. The relationships of apomictic clones to sexual populations, for example possible hybridization, require further study. Apomictic clones of Hanguana are associated with uneven ploidy levels.

The existence of the type material indicated in the protologues of all Indian curcuma species names is confirmed or excluded following visits to numerous herbaria. Lectotypes, neotypes and epitypes are designated for previously untypified names o rnames for which the holotype is missing. Earlier ineffective or superfluous typifications are discussed, several new synonyms are recognised and notes on critical taxa are provided.

The Identity of Curcuma zedoaria (Christm.) Roscoe and its nomenclatural history are explained. Roscoe wrongly interpreted the basionym of this name and applied his combination to different taxon, which is not even involved in Christmann's protologue. The first lectotypification applied the name to the species upon which Rheede's description of Kua was based. Study of living material reveals that the name C. zedoaria (Christm.) Roscoe is currently applied to several superficially similar taxa in different parts of India and SE Asia and there are no grounds to propose conservation of the name with a different type. To avoid more confusion, the identity of the plant representing C. zedoaria in the sense lectotypified by Burtt (1977) is explained here and a colour plate depicting its morphology is provided. The plant described and depicted by Roxburgh as Curucuma zerumbet Roxb., a name usually cited among synonyms of C. zedoaria (Christm.) Roscoe, is found to represent the taxon that Roscae had in mind while publishing his combination C. zedoaria (Christm.) Roscoe. Curcuma zerumbet Roxb. is illegitimate, however, and as there is no other name available or this taxon it is described here as Curcuma picta. The nomenclatural history of Amomum zerumbet J. König nom. illeg. and Erndlia subpersonata Giseke, names which are involved in the illegitimacy of C. zerumbet Roxb., is explained.