The botanical history of gymnosperm classification was reviewed and dividied into six major phases since the initiation of modern taxonomy in 1753 according to landmark concepts or creative classifications. The first phase lasted from Linnaeus to Brown during which the concept of gymnosperm was not conceived, and gymnosperms were not treated as a taxon. This phase was represented by the sexual system of Linnaeus. The second phase was from Brown to Brongniart. In this phase, the concept of gymnosperms was proposed and gradually accepted by botanists at that time, and Brongniart treated gymnosperms as a group in his classification system though the linear sequence, family delineation and relationships among taxa were ambiguous. The third phase was from Brongniart to Braun. In this phase, the gymnosperms were treated as a group within dicotyledons, the classification of Bentham & Hooker was considered as the representative classification systems. The fourth phase was from Braun to Pilger. During this period, the gymnosperms were treated as a separate taxon from angiosperms, the spermatozoids of cycads and ginkgo were discovered, the main lineages of gymnosperms became established, but the family delineation remains ambiguous, representative systems include Eichler and Engler. The fifth phase was from Pilger to Christenhusz et al.. Numerous classifications of gymnosperms were proposed in this phase, various categories were applied to lineages of gymnosperms, different lines of evidence were obtained and utilized including morphology, anatomy, embryology, phytochemistry, palaeobotany, cladistics, the focuses of debates were mainly on the relationships and systematic positions of ginkgo, taxads, and gnetophytes, and the taxonomic delineation of Podocarpaceae, Taxodiaceae and Cupressaceae, the classification systems of Pilger and Wanchun Cheng were representative in this phase. The sixth phase was from Anderson et al. till now. In this phase, people accepted the principles of cladistics, and conducted phylogenetic studies using DNA sequences, and also integrated different lines of evidences in taxonomy. The new classification of gymnosperms proposed by Yang et al. was introduced and the features of this new classification was discussed. Future studies should focus on species delimitation based on Genomic barcoding, integrative taxonomy, and conservation biology.
As a distinguished dendrologist, forester, and forestry educator, Professor Cheng Wan-chun (1904-1983) devoted his life to the pursuit of dendrology science and education. As a learner of dendrology, he was diligent and eager to learn, lucky to meet good tutors, and had a well-rounded approach to his studies. As a dendrologist, he specialized in tree classification, focusing on gymnosperms, and expanding his academic boundaries from dendrology to forest geography. As a teacher of dendrology, he advocated cultivating virtue and talent, emphasized the cultivation of practical abilities, and implemented the feedback of scientific research in teaching. Professor Cheng Wan-chun regarded forest areas as the best laboratory of dendrology and personally visited forest areas such as West Tianmu Mountain in Zhejiang, Western Sichuan, and Lichuan in Hubei, collecting a large number of plant specimens, including types. Professor Cheng Wan-chun made many contributions to dendrology, discovering and naming one new family, five new genera, and 139 new species (including varieties). The most important contribution was the discovery of Metasequoia and the proposal of a classification system for gymnosperms.
The history of the systematic of the family Styracaceae is reviewed. The multidisciplinary evidences of Styracaceae systematics was censused and it was found that leaf architecture, anatomy, pollen morphology, cytology, chromosome number and molecular systematics are of great value for the circumscription of the family and genus. The basal chromosome number (n) of Styrax is 8 while n=12 in Halesia, Pterostyraxs, Changiostyrax and Sinojackia. The molecular evidences indicate that the family Styracaceae can be divided into four clades, Styrax and Huodendron are two basal divergent clade, Alniphyllum and Bruinsmia form sister groups, and all other genera form a clade. According to these evidences, a new infrafamilial classification of the family is proposed. The family is divided into four tribes, viz., Styraceae, Huodendreae, Alniphylleae and Halesieae. Styraceae include Styrax, Huodendreae include Huodendron, Alniphylleae include Alniphyllum and Bruinsmia, while Halesieae include all other genera; Additionally, Chengiostyrax, a new genus is separated from Pterostyrax.
Cupressus L., the type of Cupressaceae family, is typified by Cupressus sempervirens L. Over the years, as many other species have been discovered and described, and with advances in phylogenetics and population genetics, the taxonomy and species diversity within the genus Cupressus have been subjects of continuous debate. Traditionally, the Cupressus sensu lato includes species from true Cypresses sensu stricto and New World cypresses (Hesperocyparis Bartel & R.A.Price), while the Cupressus s. s. comprises all Old World species except the Vietnamese golden cypress (Xanthocyparis vietnamensis Farjon & T.H.Nguyên) found in Vietnam. Christenhusz et al. defined the broadest interpretation of Cupressus (Cupressus sensu Christenhusz) which encompasses four groups: true cypresses (Cupressus s.s.), Vietnamese golden cypress, Nootka cypress (Callitropsis nootkatensis (D.Don) Oerst), and New World cypresses. These ideas have been challenged by recent phylogenomic studies. Recent studies have shown that Cupressus s.l. is non-monophyletic, Cupressus s.s. is monophyletic and forms a sister group with the genus Juniperus. The common ancestor of these two is a sister group of the common ancestors of the Xanthocyparis, Callitropsis and Hesperocyparis. Based on current research, the true cypresses should encompass 14 species, including one hybrid. This paper offers new perspectives on previous contentious taxonomic treatments, for instance, reclassifying Cupressus rushforthii Maerki & J.Hoch as a synonym of Cupressus austrotibetica Silba, and confirming that Cupressus × jiangeensis N. Zhao is a hybrid offspring of the Cupressus fallax Franco and Cupressus funebris Endlicher. Additionally, Cupressus ×wangii J.Hoch, Maerki & Rushforth has been reduced to a synonym of Cupressus × jiangeensis. To avoid confusion, it is recommended to rename the recently discovered tallest tree species in Bomi County, Cupressus austrotibetica, to “西藏高柏” (Xizang tall cypress) in Chinese, and the cypress predominantly found in Nepal, Cupressus torulosa D.Don ex Lamb., is referred to as “喜马拉雅柏” (Himalayan cypress) in Chinese, instead of “西藏柏木” (Xizang Cypress). To ensure accuracy and scientific validity in future studies on species delineation within the genus, we recommend integrating multidimensional data from morphology, genetics, ecology and biogeography. This approach will help the reducing of classification confusion and support biodiversity conservation efforts more effectively.
Reviewed and summarized the research history of the taxonomy of the subgenus Prunus subgen. Cerasus, provided an overview of major classification systems of the subgen. Cerasus. Summarized the advances in experimental taxonomy studies on the subgen. Cerasus, It is found that morphological markers play an important role in the classification of subgen. Cerasus. SSR marker studies can provide evidence for discussions on interspecific and intraspecific relationships within the subgen. Cerasus, DNA sequence markers have made important achievements in the study of subgen. Cerasus classification, essentially clarifying the phylogenetic relationships within the subgen. Cerasus. Integrated the latest data on phylogeny and geographic distribution of the subgen. Cerasus, outlined the main framework of the phylogeny of the subgen. Cerasus, speculation that the origin of this subgenus is from the Himalayan region to southwestern China or the Mediterranean region, summarized the main migration routes of the subgen. Cerasus. By combining literature and specimen data, field surveys and recent research conclusions, a total of 76 species of the subgen. Cerasus (including 11 varieties) were listed in the world species catalog, and statistical analysis was conducted on the main distribution areas and groups of the subgen. Cerasus; proposed classification viewpoints for the P. serrulata complex, P. subhirtella complex, and other controversial groups. A comprehensive analysis of the status of the taxonomy of the subgen. Cerasus, suggesting that more in depth research is needed on the complex and controversial groups within the subgen. Cerasus, as well as resource surveys and classification in the central and western regions; exploring combinations of multiple species, populations, and omics at a large scale is an important direction for the taxonomy research of the subgen. Cerasus.
【Objective】 The genus Osmanthus Lour. species represented by sweet osmanthus has high economic and research values. However, species relationships within the genus have been controversial due to the lack of distinct morphological characters among species, and there is an urgent need for a taxonomic revision of the sectional relationships within the genus. 【Method】 This study integrates multiple lines of evidence from morphological characters and molecular phylogeny to define section-level taxonomic units within the genus. Taxonomic treatments were provided based on taxonomic principles and nomenclatural codes. 【Result】 Here we propose to divide the genus Osmanthus into four sections, first retaining O. sect. Osmanthus and O. sect. Siphosmanthus Franch.; secondly, creating a new section with O. decorus (Boiss. & Balansa) Kasapligil; then creating a new section with O. yunnanensis (Franch.) P. S. Green and O. serrulatus Rehder; and finally, merging O. sect. linocieroides P. S. Green into O. sect. Osmanthus. These four sections are all strongly supported morphologically, phylogenetically and geographically. 【Conclusion】 The new revision ensures the phylogenetic relationships of each group are monophyletic and morphologically specific, which makes the species relationships more consistent with the evidence of systematic evolution, and provides an important reference for future scientific research and resource conservation and utilization.
【Objective】 The efficiency of selection and long-term testing costs for clonal propagation candidates of Cunninghamia lanceolata were improved by implementing a short-term nursery test with 67 clonal propagation candidates. By analyzing the genetic variation of growth traits and the impact of genetic environmental interactions on the selection of various traits of clones during the seedling stage, this study explores strategies for ultra early selection of clone seedlings. 【Method】 A selection procedure was conducted from a population of two million seedlings, with 275 well performing individuals selected for further prorogation. The seeds were collected from a local third generation C. lanceolata seed orchard.The selected plants were propagated into clones by hedged cutting. Of the propagated clones, 67 individuals with a fine rooting ability were selected for further testing under a completely random block design with 12 plants per plot and 10 replications. Four traits (seedling height, diameter above ground, number of branches and the length of the longest branch) were measured after one year’s growth. Furthermore, a phenotypic analysis of variance model was constructed to estimate the values of genetic variance component and genetic environmental interaction effect variance component, and ASReml software was used to estimate in heritance and repeatability, respectively. 【Result】 After planting in the nursery for one year, the average seedling height, ground diamete, number of lateral branches and longest lateral branch length of the tested clones were 0.640 m, 1.010 cm, 10.30 and 0.28 m, respectively. The phenotypic variation coefficients of the four observed traits were 12.86%, 14.88%, 21.34% and 14.89%, respectively. There were notable genetic differences found in the traits of seedling height, diameter above ground, number of lateral branches, and length of the longest lateral branches among the tested clones, and the repeatability of the measured traits exceeded 0.74, and the estimated heritability remained stable at around 0.48. The variance component of the genetic and environmental interaction accounted for about 35% of the total genetic variance. There is a significant correlation between ground diameter and seedling height, number of lateral branches, and length of the longest lateral branch, with genetic correlation coefficients above 0.9. The genetic gain estimates of seedling height, number of lateral branches, and longest lateral branch length gradually increase with the decrease of selection rate based on the ground diameter trait. However, the variance ratios of repeatability, heritability, and genetic environmental interaction of seedling height, number of lateral branches, and longest lateral branch length remain within a relatively stable range, exhibiting varying degrees of wavy fluctuations. As the selection rate decreases, the value of repeatability and heritability of ground diameter decrease, while the variance ratio of genetic environmental interaction increases. When the selection rate decreased to below 40%, the genetic environmental interaction variance ratios of the three traits of seedling height, number of lateral branches, and longest lateral branch length of C. lanceolata clones reached 41.18%-48.61%, 37.82%-40.13% and 39.61%-54.37%, respectively. However, the genetic environmental interaction variance ratio of diameter rapidly increased from 45.91% to 94.33%.When the number of selected clones decreased from 19 to 16, the genetic environmental interaction variance ratios of ground diameter heritability and genetic environmental interaction variance ratios changed significantly, with diameter heritability decreasing from 0.226 3 to 0.091 4 and genetic environmental interaction variance ratios rapidly increasing from 63.09% to 83.26%. Based on a selection rate of approximately 30%, 19 clones were selected for further evaluation in multiple sites in a long-term afforestation project in a mountain area. The average seedling height, ground diameter, number of lateral branches, and longest lateral branch length of the selected clones were 0.73 m, 1.20 cm, 12.4 branches and 0.33 m, respectively. The estimated average genetic gains of the four observed traits were 10.81%, 15.45%, 16.66% and 13.88%, which were 14.06%, 18.81%, 20.39% and 17.86% higher than the population average, respectively. 【Conclusion】 The effect of genetic environmental interaction on the phenotypic traits of C. lanceolata clones cannot be ignored, and its interaction variance accounts for a large proportion of the total genetic variance. The growth of height and lateral branches of C. lanceolata clones are relatively less affected by the genetic environmental interaction effect, while the growth of ground diameter are more sensitive to changes in the microenvironment of the nursery or from unknown factors. Therefore, combining the growth performance of tree height and ground diameter of C. lanceolata clones for short-term testing can achieve ideal of selection. Reducing the selection rate does not eliminate the influence of genetic environmental interaction on ground diameter and longest lateral branch length. High intensity selection can actually increase the influence of genetic environmental interaction. Appropriate selection intensity can not only retain the richness of genetic variation in target traits between clones, but also fix most of the genetic environmental interaction effects. Short-term nursery testing can serve as a rapid preliminary screening technique, especially when there is a large amount of clonal candidates to be tested. Several benefits were apparent, including forest-land use and the long-term cost efficiency of testing. The clonal traits, genetic components, and interaction between genetics and environment could be evaluated in the super-early stage of clonal evaluation.
