Primulina malipoensis (Gesneriaceae), a new species from Sino-Vietnamese border area.
ABSTRACT: Primulina malipoensis, a new species from limestone areas around the Sino-Vietnamese border, is described and illustrated. This new species is morphologically similar to P. maguanensis and P. lungzhouensis, but obviously differs from the latter two species by its pale greenish-yellow flowers (vs. purple, with different colour patterns). The phylogenetic affinity, illustration and photographs of this new species are provided in this paper.
Project description:The limestone regions of Yunnan-Guangxi-Guizhou in southern and southwestern China are regarded as some of biodiversity's hotspots for China's Gesneriaceae where numerous rare new species of Primulina have been, or are being, described over the past two decades. Primulina flexusa, a new lithophytic species of Gesneriaceae from a limestone hill in a Karst area, from Guizhou, China, is described here with color photographs. It is similar to P. curvituba, but can be easily distinguished by a combination of characteristics, especially in the shape and length of its capsule. We found only one population with approximately 100 mature individuals at the type locality. This new species is provisionally assessed as Critically Endangered [CR C1] by using IUCN criteria.
Project description:Primulina serrulata R.B.Zhang & F. Wen, a new species from a limestone area in southeastern Guizhou, China, is described and illustrated here. The new species is morphologically related to P. fimbrisepala (Hand.-Mazz.) Y.Z.Wang. We examined the morphological differences between these congeners and provide illustrations and photographs of this new species in this paper.
Project description: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.
Project description:BACKGROUND:The Gesneriaceae genus Chiritopsis, confined almost exclusively to cave or cave-like microhabitats of limestone karsts of southern China, was described to distinguish it from Chirita by much smaller flowers and generally miniature plant sizes in the former genus. However, molecular phylogenetic analyses showed that Chiritopsis is polyphyletic and its species delimitation has been problematic. To understand how many times Chiritopsis-like species have evolved from within the recircumscribed Primulina and to further clarify their species identification, we sampled all but two recently described species of Chiritopsis-like Primulina and reconstructed their phylogenetic relationship based on DNA sequences of nuclear ITS and chloroplast trnL-F and trnH-psbA. RESULTS:With 182 accessions of 165 taxa of Primulina sampled, our analyses placed the 40 accessions of 25 taxa of Chiritopsis-like Primulina in 17 unrelated positions, indicating at least 17 independent origins of the traits associated with caves or cave-like microhabitats. Of the 17 clades containing Chiritopsis-like Primulina, Clade 1 is composed of P. bipinnatifida, P. cangwuensis, P. jianghuaensis, P. lingchuanensis, and P. zhoui, as well as additional samples that show variable and overlapping morphology in leaf shapes. Clade 10 includes P. cordifolia, P. huangii, and P. repanda, while Primulina repanda var. guilinensis is not placed within Clade 10. Primulina glandulosa var. yangshuoensis is not placed in the same clade of P. glandulosa. CONCLUSIONS:Based on our data, P. cangwuensis, P. jianghuaensis, and P. lingchuanensis are proposed to synonymize under P. bipinnatifida, with P. zhoui treated as a variety of P. bipinnatifida. Primulina repanda var. guilinensis is transferred as P. subulata var. guilinensis comb. nov. and Primulina pseudoglandulosa nom. nov. is proposed for P. glandulosa var. yangshuoensis. One new species is named P. chingipengii to honor the late Dr. Ching-I Peng (1950-2018).
Project description:Primulina jiuyishanica K. Liu, D.C. Meng & Z.B. Xin, a new species of Gesneriaceae from Hunan, China, is described and illustrated. The new species is morphologically similar to Primulina fimbrisepala (Hand.-Mazz.) Yin Z. Wang, but differs in its elliptic to broadly elliptic leaf blade with broadly cuneate base, peduncle densely pubescent with sparse glandular hairs, corolla throat with no purple spots inside, the yellow patch in the throat densely glandular-pubescent and pistil densely glandular-pubescent. Photographs and descriptions of the new species are provided below.
Project description:The picturesque limestone karsts across the Sino-Vietnamese border are renowned biodiversity hotspot, distinguished for extremely high endemism of calciphilous plants restricted to caves and cave-like microhabitats that have functioned as biological refugia on the otherwise harsh habitats. To understand evolutionary mechanisms underlying the splendid limestone flora, dated phylogeny is reconstructed for Asian Begonia, a species-rich genus on limestone substrates represented by no less than 60 species in southern China, using DNA sequences of nrITS and chloroplast rpL16 intron. The sampling includes 94 Begonia species encompassing most major Asian clades with a special emphasized on Chinese species.Except for two tuberous deciduous species and a species with upright stems, a majority of Sino-Vietnamese limestone Begonia (SVLB), including sect. Coelocentrum (19 species sampled) and five species of sect. Diploclinium, Leprosae, and Petermannia, are rhizomatous and grouped in a strongly supported and yet internally poorly resolved clade (Clade SVLB), suggesting a single evolutionary origin of the adaptation to limestone substrates by rhizomatous species, subsequent species radiation, and a strong tendency to retain their ancestral niche. Divergence-time estimates indicate a late Miocene diversification of Clade SVLB, coinciding with the onset of the East Asian monsoon and the period of extensive karstification in the area.Based on our phylogenetic study, Begonia sect. Coelocentrum is recircumscribed and expanded to include other members of the Clade SVLB (sect. Diploclinium: B. cavaleriei, B. pulvinifera, and B. wangii; sect. Leprosae: B. cylindrica and B. leprosa; sect. Petermannia: B. sinofloribunda). Because species of Clade SVLB have strong niche conservatism to retain in their ancestral habitats in cave-like microhabitats and Begonia are generally poor dispersers prone to diversify allopatrically, we propose that extensive and continuous karstification of the Sino-Vietnamese limestone region facilitated by the onset of East Asian monsoon since the late Miocene has been the major driving force for species accumulation via geographic isolation in Clade SVLB. Morphologically species of Clade SVLB differ mainly in vegetative traits without apparent adaptive value, suggesting that limestone Begonia radiation is better characterized as non-adaptive, an underappreciated speciation mode crucial for rapid species accumulations in organisms of low vagility and strong niche conservatism.
Project description:A new Primulina species from Guangdong, China with an unusual inflorescence is described here. Primulina anisocymosa is vegetatively most similar to P. bobaiensis. It can be distinguished from all species within Primulina morphologically by its unique zigzag monochasial cyme and infructescence. To confirm the phylogenetic relationships and generic placement of this species, not only morphological anatomical features but also chromosome and DNA sequence data were examined and analysed here. Two samples from different populations identified as Primulina anisocymosa are monophyletic and were nested in a monophyletic clade within Primulina with high branch support. The somatic chromosome number of the new species is also reported (2n = 36), supporting its placement in the genus.
Project description:Limestone Karst areas possess high levels of biodiversity and endemism. Primulina is a typical component of Karst endemic floras. The high species richness and wide distribution in various Karst microenvironments make the genus an idea model for studying speciation and local adaptation. In this study, we obtained 10 full-length sequences of the phytochrome PHYE from available transcriptome resources of Primulina and amplified partial sequences of PHYE from the genomic DNA of 74 Primulina species. Then, we used maximum-likelihood approaches to explore molecular evolution of PHYE in this Karst cave plant. The results showed that PHYE was dominated by purifying selection in both data sets, and two sites were identified as potentially under positive selection. Furthermore, the ? ratio varies greatly among different functional domains of PHYE and among different species lineages. These results suggest that potential positive selection in PHYE might have played an important role in the adaption of Primulina to heterogeneous light environments in Karst regions, and different species lineages might have been subjected to different selective pressures.
Project description:Limestone karsts in southern China are characterized by high edaphic and topographic heterogeneity and host high levels of species richness and endemism. However, the evolutionary mechanisms for generating such biodiversity remain poorly understood. Here, we performed species delimitation, population genetic analyses, simulations of gene flow and analyses of floral morphological traits to infer the geographic history of speciation in a species complex of Primulina eburnea from limestone karsts of southern China. Using Bayesian species delimitation, we determined that there are seven distinct species that correspond well to the putative morphological species. Species tree reconstruction, Structure and Neighbor-Net analyses all recovered four lineages in agreement with currently species geographic boundaries. High levels of genetic differentiation were observed both within and among species. Isolation-migration coalescent analysis provides evidence for significant but low gene flow among species. Approximate Bayesian computation (ABC) analysis supports a scenario of historical gene flow rather than recent contemporary gene flow for most species divergences. Finally, we found no evidence of divergent selection contributing to population differentiation of a suite of flower traits. These results support the prevalence of allopatric speciation and highlight the role of geographic isolation in the diversification process. At small geographic scales, limited hybridization occurred in the past between proximate populations but did not eliminate species boundaries. We conclude that limited gene flow might have been the predominant evolutionary force in promoting population differentiation and speciation.
Project description:Five new species of Primulina (Gesneriaceae) are described and illustrated here, namely P.purpureokylin F. Wen, Yi Huang & W. Chuen Chou, P.persica F. Wen, Yi Huang & W. Chuen Chou, P.cerina F. Wen, Yi Huang & W. Chuen Chou, P.niveolanosa F. Wen, S. Li & W. Chuen Chou and P.leiyyi F. Wen, Z.B. Xin & W. Chuen Chou. The characteristic traits of these species, together with photographs, detailed descriptions, notes on etymology, distribution, and habitat, as well as comparisons with morphologically similar species, are provided.