Six new species of Begonia from Guangxi, China.

BACKGROUND: With currently 1980 described species, the mega-diverse Begonia is now perhaps the 5th largest flowering plant genus, expanding rapidly from ca. 900 species in 1997 to its current size in merely two decades. In continuation of our studies of Asian Begonia, we report six additional new species from Guangxi, the region/province harboring the second richest Begonia flora of China. RESULTS: Based on morphological and molecular data, the new species B. aurora belongs to Begonia sect. Platycentrum, while the other five new species (viz. B. larvata, B. longiornithophylla, B. lui, B. scabrifolia, and B. zhuoyuniae) are members of Sect. Coelocentrum. Somatic chromosome numbers of B. longiornithophylla and B. zhuoyuniae at metaphase were counted as 2n = 30, consistent with previously reports for Sect. Coelocentrum. CONCLUSIONS: With the addition of the six new species, the total number of Begonia species in Guangxi increases from 86 to 92. Detailed description, line drawings, and color plates are provided to aid in identification.

Three new species of Begonia sect. Baryandra from Panay Island, Philippines.

BACKGROUND: The flora of Panay Island is under-collected compared with the other islands of the Philippines. In a joint expedition to the island, botanists from Taiwan and the Philippines found three unknown Begonia species and compared them with potentially allied species. RESULTS: The three species are clearly assignable to Begonia sect. Baryandra which is largely endemic to the Philippines. Studies of literature, herbarium specimens, and living plants support the recognition of the three new species: Begonia culasiensis, B. merrilliana, and B. sykakiengii. Somatic chromosomes at metaphase were determined to be 2n = 30 for B. culasiensis and 2n = 28 for both B. merrilliana and B. sykakiengii, congruent with those of most species in sect. Baryandra. Molecular phylogenetic evidence is consistent with B. culasiensis being a relict from the late Miocene and B. merrilliana and B. sykakiengii being younger species of Pleistocene origin. CONCLUSION: The continuing discovery of endemic Philippine species means the remaining fragments of both primary and secondary native vegetation in the archipelago are of increasing value in terms of natural capital. A secure future for the species could be realized through ex situ conservation collections and raising awareness with community groups.

Begonia myanmarica (Begoniaceae), a new species from Myanmar, and molecular phylogenetics of Begonia sect. Monopteron.

BACKGROUND: A new species, Begonia myanmarica, was discovered from Myanmar and herein documented. Characterized by a single developed wing in the ovary/fruit, this species would be assigned to sect. Monopteron (sensu Doorenbos et al. in The sections of Begonia including descriptions, keys and species lists: studies in Begoniaceae VI. Wageningen Agricultural University, Wageningen, 1998) that is known by B. griffithiana and B. nepalensis from the Himalaya. To confirm its sectional assignment, we conducted morphological, phylogenetic and cytological studies. RESULTS: Morphological observations indicated that B. myanmarica was distinguishable from the two known species of sect. Monopteron by the leaf shape and size, 1-locular ovary, parietal placentation and chromosome number. Molecular phylogenetic analysis using nrITS sequences showed that B. myanmarica was not allied with the clade of sect. Monopteron, though both were nested within sect. Platycentrum-sect. Sphenanthera clade. CONCLUSIONS: Studies of morphology, molecular phylogenetics and cytology support the recognition of the new species, Begonia myanmarica, which is fully described and illustrated. Our results also indicate that B. myanmarica is not closely related to species previously assigned to sect. Monopteron, suggesting that the fruit morphology of a single developed wing in the ovary/fruit characterizing sect. Monopteron is homoplasious.

Two new species of Begonia, B. moneta and B. peridoticola (Begoniaceae) from Sabah, Malaysia.

BACKGROUND: Mount Kinabalu, reknowned for its high biodiversity and endemism, is a National Park in the State of Sabah on the northern end of the island of Borneo. Every year many visit the higher part of the Kinabalu National Park, while most lowland forests in the Park are under-explored. Two unknown species of Begonia were collected from a peridotic (ultramafic) cliff in the Kinabalu National Park at ca. 400 m elevation. RESULTS: The two species are named B. moneta C.-I Peng, Rimi & C. W. Lin and B. peridoticola Rimi, C.-I Peng & C. W. Lin. Begonia moneta (sect. Baryandra) is similar to B. gueritziana Gibbs, a widespread species of the same section in Borneo, differing in the peltate (vs. basifixed) leaves and the smaller flower parts. Also, their chromosome numbers are different (B. moneta, 2n = 30; B. gueritziana, 2n = 28). The peltate and succulent foliage of B. moneta is also reminiscent of B. burttii Kiew & S. Julia and B. payung S. Julia & Kiew, both of sect. Reichenheimia, from Sarawak. Begonia moneta is distinct from the two species in having branched (vs. entire) placental lamellae. Additionally, B. moneta differs from B. burttii in having 4 (vs. 5) tepals in pistillate flowers and markedly unequal (vs. equal) fruit wings. Begonia moneta differs from B. payung in the smaller leaves and conspicuously winged (vs. wingless) capsules. Begonia peridoticola (sect. Petermannia) resembles B. punchak Kiew & S. Julia from limestone areas in Kuching Division, Sarawak, differing in the entire leaf margin (vs. distantly dentate), much larger capsular wings (8-11 mm vs. 2-3 mm wide) and yellow, spiral (vs. crimson, U-shaped) styles. CONCLUSION: A careful study of the herbarium materials and literature supports the recognition of the two new species. Detailed descriptions, line drawings, color plates, chromsome data, foliar SEM observations and comparisons with phenetically similar species are provided to aid in identification.

Six new species of Begonia (Begoniaceae) from limestone areas in Northern Vietnam.

BACKGROUND: Species of Begonia are richly represented in limestone karst areas across the Sino-Vietnamese border. More than one hundred species were known, many of which were documented recently. RESULTS: In continuation of our systematic studies of Asian Begonia, we report six species of Begonia that are unknown to science, namely B. caobangensis [sect. Platycentrum], B. circularis, B. melanobullata, B. langsonensis, B.locii and B. montaniformis [sect. Coelocentrum] from Northern Vietnam. Diagnostic features that separate them from morphologically allied species are provided. Somatic chromosome numbers were determined, which supports their placement in the respective sections. Foliar SEM microphotographs were taken and described. CONCLUSION: A careful study of the literature, herbarium specimens and living plants, both in the wild and in cultivation in the experimental greenhouse, supports the recognition of the six new species, which are described and illustrated.

Three new species of Begonia endemic to the Puerto Princesa Subterranean River National Park, Palawan.

BACKGROUND: Begonia is a mega-diverse genus of flowering plants prone to generating micro-endemic species, especially on limestone habitats. During fieldwork in the Puerto Princesa Subterranean River National Park, Palawan (Philippines), three species were encountered which did not match any previously described from the region. RESULTS: Following morphological, anatomical, molecular phylogenetic and cytological investigation a hypothesis of three new species is supported. The three new species belong to a clade endemic to Palawan and Borneo. CONCLUSIONS: The limestone habitats in the Puerto Princesa Subterranean River National Park environs support a unique flora. The description of three new species from a small area within the park demonstrates how much remains to be discovered there, and the importance of its continued protection.

Ixeridium calcicola (Compositae), a new limestone endemic from Taiwan, with notes on its atypical basic chromosome number, phylogenetic affinities, and a limestone refugium hypothesis.

A new species Ixeridium calcicola (Compositae) endemic to middle altitude (ca 1,000-2,000 m asl) limestone mountains of eastcentral Taiwan is described based on morphological and chromosome cytological observations and molecular phylogenetic analyses. Ixeridium calcicola resembles Ixeridium transnokoense, endemic to upper montane and alpine ranges (2,600-3,500 m asl) of Taiwan, in the dwarf habit, but differs in the oblong to lanceolate leaf blades (vs. linear to linear-lanceolate), the presence of mucronulate teeth on the leaf margin and petiole (vs. smooth to very sparse), the dark purple lower leaf surface (vs. greenish), the capitulum with 10 to 12 florets (vs. 5 to 7) and 8 to 10 inner phyllaries (vs. 5, rarely to 7). The basic chromosome number in Ixeridium was known as X = 7. However, the new species has a basic chromosome number of X = 8, as recorded also in the closely related Ixeris. Molecular phylogenetic analyses with the expanded sampling of Ixeridium and Ixeris including both type species supported the monophyly of each of the genera and the placement of the new species in Ixeridium. The result of the phylogenetic analyses and detailed observation of the chromosome morphology revealed that X = 8 in Ixeridium calcicola is derived from centric fission in an ancestral karyomorphotype with X = 7 in Ixeridium. Ixeridium calcicola and Ixeridium transnokoense formed a Taiwan endemic lineage and their estimated divergence time was in the middle Pleistocene. Their common ancestral lineage may have experienced altitudinal distribution shifts in response to glacial-interglacial temperature fluctuation, and a lineage which had not retreated to alpine ranges in an interglacial period likely survived in a limestone refugium, where ordinary plant species did not grow, leading to allopatric speciation.

Begonia wuzhishanensis (sect. Diploclinium, Begoniaceae), a new species from Hainan Island, China.

BACKGROUND: Hainan is the largest island of the Indo-Burma Biodiversity Hotspot and has the best preserved and most extensive tropical forests in China. A recent study on distribution of endangered species in China identifies southern Hainan as one of eight hotspots for plant conservation in the country. In continuation of our studies of Asian Begonia, we report the discovery of an attractive undescribed species, B. wuzhishanensis C.-I Peng, X.H. Jin & S.M. Ku, from Hainan Island. RESULTS: Living plant of the new species, Begonia wuzhishanensis, was collected in 2009 and cultivated in the experimental greenhouse for morphological and cytological studies. It flowered consecutively in 2012 and 2013 in the experimental greenhouse, Academia Sinica. It was assigned to the large, heterogeneous sect. Diploclinium. The chromosome number of this new species was determined to be 2n = 26. CONCLUSIONS: A careful study of literature, herbarium specimens and living plants, both in the wild and in cultivation, support the recognition of the new species Begonia wuzhishanensis, which is described in this paper. Begonia wuzhishanensis is currently known only from Fanyang, Wuzhishan Mountain in the center of the island. A line drawing, color plate, and a distribution map are provided to aid in identification.

Begonia wui-senioris (sect. Platycentrum, Begoniaceae), a new species from Myanmar.

BACKGROUND: The flora of Myanmar is under-collected compared with all other tropical Asian countries. An unknown Begonia was grown from seeds collected from a limestone hill in Central Myanmar, and compared with potentially allied species. RESULTS: The unknown Begonia is rhizomatous, has peltate leaves, 2-locular ovaries, and is evergreen. It is clearly assignable to sect. Platycentrum. Only two other species of Begonia, B. josephii and B. subperfoliata, in Myanmar have peltate leaves, but they are deciduous tuberous plants with 3-locular ovaries and belong to sect. Diploclinium. CONCLUSIONS: Thorough studies of literature and herbarium materials support the recognition of a new species, Begonia wui-senioris, which is fully described and illustrated. Begonia wui-senioris has the lowest chromosome number (2n = 14) for the genus.

Two new species of Begonia sect. Coelocentrum, B. guixiensis and B. longa, from Sino-Vietnamese limestone karsts.

BACKGROUND: In our recent molecular phylogenetic study of Asian Begonia, two undescribed species, B. guixiensis sp. ined. (S. Guangxi, China) and B. longa sp. ined. (Vietnam), were sampled and placed within the strongly supported clade composed of Begonia sect. Coelocentrum and other co-distributed rhizomatous species in the Sino-Vietnamese limestone karsts. While Begonia sect. Coelocentrum has been recircumscribed based on the phylogenetic relationships, B. guixiensis sp. ined. and B. longa sp. ined. remain illegitimate names. In continuation of our studies in Asian Begonia, these two new species are described and illustrated. RESULTS: Begonia guixiensis resembles B. cylindrica in the peltate, subcoriaceous leaves, differing by the shape of ovary/fruit and the type of placentation. In aspect, B. longa bears a superficial resemblance to B. brevipedunculata in leaf shape in particular, differing by many other features such as the long internodes, shorter petioles and smaller leaves, longer peduncles and 3-locular ovary. The chromosome number of both new species is determined as 2n = 30. CONCLUSION: A careful study of the literature, herbarium specimens and living plants, both in the wild and in cultivation in the experimental greenhouse, support the recognition of the two new species, which are described and illustrated herein.

Begonia jinyunensis (Begoniaceae, section Platycentrum), a new palmately compound leaved species from Chongqing, China.

BACKGROUND: Continental China is the center of Begonia species diversity in Asia and contains more than 60 species out of about 110 named species of section Platycentrum. Mt. Jinyun, located in Chongqing City at the upper reaches of the Yangtze River, harbors a subtropical broadleaved forest with high species diversity. During a botanical survey in Mt. Jinyun, an unknown Begonia species of sect. Platycentrum with palmately compound leaves was collected and studied based on detailed morphological observations and cytological and molecular phylogenetic analyses. RESULTS: The unknown Begonia bears a superficial resemblance to B. hemsleyana in having palmately compound leaves, a feature unseen in other species of sect. Platycentrum in China. It is however sharply distinct from the latter in the acaulous habit with aerial stems seen only at anthesis and long rhizomes (vs. erect stems to 70 cm or taller with short rhizomes), 4-6 pinnatilobed leaflets with indistinct, decurrent petiolules (vs. 7-10 serrate leaflets with distinct petiolules), and white (vs. pink) tepals. Molecular phylogenetic analyses based on nuclear ribosomal DNA and chloroplast DNA sequences indicated that this species was allied to Platycentrum species occurring in Southwest and South-central China and Vietnam, including B. hemsleyana, and clearly separable from these species. Somatic chromosome number of 2n = 22 was reported for this unknown species. The diploid chromosome number is agreeable with those published for Begonia sect. Platycentrum. CONCLUSIONS: The unknown Begonia is confirmed to be a new species of sect. Platycentrum and hereto described as Begonia jinyunensis C.-I Peng, B. Ding & Q. Wang.

Primulina cardaminifolia (Gesneriaceae), a rare new species from limestone areas in Guangxi, China.

BACKGROUND: Primulina cardaminifolia Yan Liu & W.B. Xu (Gesneriaceae), a distinct new species with imparipinnate leaves, is described and illustrated from a limestone valley in Guangxi Zhuangzu Autonomous Region, China. To assure its generic placement and phylogenetic affinity, phylogenetic analyses were performed using DNA sequences of nuclear ITS and chloroplast trnL-F intron spacer region. Additionally, somatic chromosome number was counted and pollen stainability was tested. RESULTS: Phylogenetic analyses support its placement in Primulina; however, two phylogenetically distinct ITS sequence types were detected, suggesting a probable hybrid origin. Its pollen stainability is 100% and its chromosome number, 2n = 36, is congruent with all known counts of diploid species of the genus. CONCLUSION: All available data support the recognition of the new species Primulina cardaminifolia and suggest that it could have derived from homoploid hybrid speciation. Color plates, line drawings and a distribution map are provided to aid in identification.

Novelties in Begonia sect. Coelocentrum: B. longgangensis and B. ferox from limestone areas in Guangxi, China.

BACKGROUND: The spectacular karst limestone landscape in Guangxi harbors high-level diversity and endemism of Begonia species, especially those of sect. Coelocentrum. In continuation of our studies in this area, we report the discovery of two attractive new species from southwestern Guangxi: Begonia longgangensis and B. ferox. RESULTS: Begonia longgangensis resembles B. liuyanii, also from Longgang Nature Reserve, in the broadly ovate to suborbicular leaf blade, differing by the much smaller leaves, subglabrous leaf surface, pink flowers, dichasial cymes and the remarkably long stolons sent out from rhizomes. Unexpectedly, both diploid (2n = 30) and triploid counts (2n = 45) were observed in plants collected from the type locality. Begonia ferox probably has the most prominent bullate leaves for the genus. In this aspect, it is similar to B. nahangensis reported from northern Vietnam recently, but is readily distinguishable by the ovate, chartaceous leaves with an acuminate apex; tomentose peduncle not exceeding petioles; and the much larger stature in vegetative parts. A diploid count of 2n = 30 was determined for this unique new species. CONCLUSIONS: All available data support the recognition of the two new species. Begonia longgangensis has remarkably long stolons and B. ferox is characterized by the prominent bullate leaves. Line drawings, color plates and comparisons are provided to aid in identification of the novelties.

Aspidistra crassifila (Asparagaceae), a new species from Guangxi, China.

BACKGROUND: Aspidistra crassifila Yan Liu & C.-I Peng, a new species of the Asparagaceae from Guangxi Zhuang Autonomous Region, China, is described and illustrated. RESULTS: The new species is similar to A. subrotata Y. Wan & C. C. Huang in the perianth lobes triangular-lanceolate and horizontally spreading, but differs by the perianth campanulate, lobes with appendages at base, stamens 6-8 mm long, filaments enlarged, anthers adnate to perianth tube, connectives extended and upcurved. The chromosome number of the new species was determined to be 2n = 38, and the karyotype was formulated as 2n = 22m2SC+4sm+12st. CONCLUSION: A careful study of the literature, herbarium specimens and living plants, both in the wild and in cultivation in the experimental greenhouse, support the recognition of the new species Aspidistra crassifila, which is described herein. Aspidistra crassifila is currently known only from Shiwandashan Mountains, which lie in southern Guangxi. A line drawing, color plates and a distribution map are given for the new species to aid in identification.

Intraspecific karyotypic polymorphism is highly concordant with allozyme variation in Lysimachia mauritiana (Primulaceae: Myrsinoideae) in Taiwan: implications for the colonization history and dispersal patterns of coastal plants.

BACKGROUND AND AIMS: Investigating intraspecific karyotypic and genetic variations jointly can provide unique insights into how historical, ecological and cytogenetic factors influence microevolution. A coastal herb, Lysimachia mauritiana, exhibits extensive karyotypic polymorphism and displays a complex cytogeographic pattern across the Ryukyus. To explore whether a similar degree of chromosomal variation exists south of the Ryukyus, and in an attempt to ascertain the mechanisms that may have generated the patterns, comprehensive sampling was conducted in Taiwan. METHODS: Karyotypes were analysed at mitotic metaphase for 550 individuals from 42 populations throughout Taiwan Proper and its adjacent islands. In addition, genetic variation was estimated using 12 allozymes (21 loci) of 314 individuals sampled from 12 localities. KEY RESULTS: Four chromosome numbers and eight cytotypes, including four endemic cytotypes, were detected. Cytotype distributions were highly structured geographically, with single cytotypes present in most populations and four major cytotypes dominating the north, east and south of Taiwan and the Penghu Archipelago. Allozyme variation was very low and F-statistics indicated an extremely high level of population differentiation, implying limited gene flow among populations. Cluster analysis of allozyme variation uncovered four geographic groups, each corresponding perfectly to the four dominant cytotypes. The geographic structure of cytotype distribution and allozyme variation probably resulted from severe genetic drift triggered by genetic bottlenecks, suggesting that Taiwanese populations were likely to be derived from four independent founder events. In the few localities with multiple cytotypes, cytogeographic patterns and inferences of chromosomal evolution revealed a trend of northward dispersal, consistent with the course of the Kuroshio Current that has been influential in shaping the coastal biota of the region. CONCLUSIONS: The data elucidate the patterns of colonization and the effects of the Kuroshio Current on the distribution of L. mauritiana in Taiwan. These inferences are highly relevant to other coastal plant species in the region and will stimulate further studies.

Extreme habitats that emerged in the Pleistocene triggered divergence of weedy Youngia (Asteraceae) in Taiwan.

Weeds with broad distributions and large morphological variation are challenging for systematists and evolutionarily intriguing because their intensive dispersal would likely prevent local morphological differentiation. Study on weeds will help to understand divergence in plants unlikely to be affected by geographical and ecological barriers. We studied Youngia japonica based on nrDNA and cpDNA sequences. This is a widespread native in Asia and invasive worldwide; nevertheless, three subspecies (japonica, longiflora, and formosana) and an undescribed variant occur in Taiwan. Bayesian and the most parsimonious phylogenies revealed that subspecies longiflora is a different linage and independently arrived in Taiwan during the Pleistocene via land connection to the Asian Continent. Bayesian time estimation suggested that Youngia in Taiwan diverged in the lower Pleistocene or more recently. Extreme habitats that emerged in the Pleistocene, i.e., cold mountain ranges for subspecies formosana and xeric, raised coral reefs for the undescribed Youngia variant probably had triggered the divergence. Components of Youngia in Taiwan are not monophyletic; a coalescent-based test suggested incomplete lineage sorting. Nevertheless, the samples within each taxon share unique morphological features suggesting a common gene pool and each taxon has different dominant ITS and/or cpDNA types; these conditions suggest ongoing process toward monophyly via coalescent processes and support the delimitation of intraspecific taxa.

Identification of genome constitutions in Begonia×chungii and its putative parents, B. longifolia and B. palmata, by genomic in situ hybridization (GISH).

Based mainly on morphological features and geographical distribution, Begonia×chungii (2n=22) was recently reported as a natural hybrid between B. longifolia and B. palmata in Taiwan. This study aims to confirm the hybridity of B.×chungii and to sort out the genome constitutions of its putative parents, using genomic in situ hybridization (GISH). Genomic DNAs of both parental species were used as probes for B.×chungii and the experimental F(1) hybrid, B. palmata×B. longifolia, in GISH analyses. Bicolor-GISH analyses in B.×chungii showed that the 22 chromosomes consisted of six chromosomes hybridized with a probe derived from the B. palmata genome, six with another probe from the B. longifolia genome and the remaining ten with both genomes overlapped. Meanwhile, bicolor-GISH in B. palmata×B. longifolia showed a remarkable similarity to that of B.×chungii. The reciprocal GISH results between B. longifolia and B. palmata were comparable. Our GISH analyses confirmed that B.×chungii is a natural F(1) hybrid between B. longifolia and B. palmata. Genomes of the parental species were shown to be partially homologous, suggesting a derived common ancestral genome in them.

Isolation of compound microsatellite markers in Begonia fenicis (Begoniaceae) endemic to East and Southeast Asian islands.

PREMISE OF THE STUDY: We developed compound microsatellite markers for Begonia fenicis, a species endemic to eastern and southeastern Asian islands, to investigate geographical genetic structure. METHODS AND RESULTS: Using the compound microsatellite marker technique, 21 markers were developed and six polymorphic markers were characterized for samples from four islands in Taiwan and southern Japan. The number of alleles per locus ranged from two to six (mean = 4.33). Observed and expected heterozygosities were 0.125-0.725 (0.383) and 0.498-0.719 (0.641), and polymorphic information content was 0.371-0.664 (0.567). The interspecific transferability of the 21 markers was evaluated for eight species of the section Diploclinium from the Philippines; 15 markers were successfully amplified in one to eight species. CONCLUSIONS: These results indicate the utility of the six microsatellite markers in B. fenicis to investigate geographical genetic structure. The transferable markers are potentially useful for other species of the section.

Molecular phylogeny and habitat diversification of the genus Farfugium (Asteraceae) based on nuclear rDNA and plastid DNA.

BACKGROUND AND AIMS: Farfugium (Asteraceae) is a small genus that contains the two species F. japonicum and F. hiberniflorum and is distributed along a long archipelago in east Asia. The common taxon, F. japonicum, includes three varieties associated with a wide range of habitats, including forest understorey (sciophytes), coastal crag (heliophytes) and riverbed (rheophytes). Leaf shape is an important taxonomic character within this genus and is associated with the habitat. METHODS: Twenty populations that included all Farfugium taxa were collected throughout its range. Leaf morphology was measured to determine differences amongst the taxa. Phylogenetic analyses based on sequences of the internal transcribed spacer of nuclear rDNA and four plastid DNA regions (matK, trnL-trnF, trnH-psbA and rpl20-rps12) were conducted separately. KEY RESULTS: Leaf morphology was significantly different amongst taxa, but morphological variations were partly explained by adaptation to certain environmental conditions that each population inhabited. Molecular phylogenies for the nDNA internal transcribed spacer and cpDNA were consistent in classifying F. hiberniflorum and the Taiwanese var. formosanum, whilst suggesting polyphyletic origins for the rheophyte, sciophyte and heliophyte taxa. All samples from the southern Ryukyus (Japan) and Taiwan clustered into a monophyletic group, which corroborates the land configuration theory involving Quaternary land-bridge formation and subsequent fragmentation into islands. The incongruence between the two DNA datasets may imply traces of introgressive hybridization and/or incomplete lineage sorting. CONCLUSIONS: The occurrence of rheophyte, sciophyte and heliophyte plants within Farfugium may be attributable to their isolation on islands and subsequent adaptation to the riparian, coastal crag and forest understorey environments, following their migration over the Quaternary land-bridge formation along their distribution range. Nearly identical DNA sequences coupled with highly divergent morphologies amongst these taxa suggest that diversification was rapid.