Serrata Var Research Articles

Phylogenetic relationships and divergence time of Hydrangea sect. Macrophyllae (Hydrangeaceae) revealed by genome-wide SNPs

Hydrangea sect. Macrophyllae comprises deciduous shrubs including two species with seven infraspecific taxa distributed throughout the Japanese Archipelago and adjacent areas. In this study, we revealed a phylogeny of Hydrangea sect. Macrophyllae by using a larger dataset of genome-wide SNPs than those employed in a previous study and by adding more comprehensive taxa/populations, which cover the entire distribution of the section. We then revised the taxonomic treatment of sect. Macrophyllae based on the higher-resolution phylogenetic trees obtained in this study. The phylogenetic trees estimated in this study showed five major clades, suggesting that H. serrata var. minamitanii and var. yesoensis should be treated as independent species from other H. serrata, that H. serrata var. australis and var. yakushimensis could be subclassified under the major clades and that var. angustata could be a synonym of var. serrata. The divergence time of these major clades was estimated to be in the Pleistocene.

Spatial Distribution and Ecological Determinants of Coexisting Hybrid Oak Species: A Study in Yushan's Mixed Forest.

Ecological niche partitioning is crucial in reducing interspecific competition, fostering species coexistence, and preserving biodiversity. Our research, conducted in a hybrid mixed oak forest in Yushan, Jiangsu, China, focuses on Quercus acutissima, Q. variabilis, Q. fabri, and Q. serrata var. brevipetiolata. Using Point Pattern Analysis, we investigated the spatial relationships and ecological trait autocorrelation, including total carbon (TC), nitrogen (TN), phosphorus (TP), potassium (TK), and breast height diameter (DBH). Our findings show aggregated distribution patterns within the oak populations. The Inhomogeneous Poisson Point model highlights the impact of environmental heterogeneity on Q. variabilis, leading to distinct distribution patterns, while other species showed wider dispersion. This study reveals aggregated interspecific interactions, with a notable dispersal pattern between Q. acutissima and Q. variabilis. We observed significant variability in nutrient elements, indicating distinct nutrient dynamics and uptake processes. The variations in total carbon (TC), nitrogen (TN), phosphorus (TP), and potassium (TK) suggest distinct nutrient dynamics, with TK showing the highest variability. Despite variations in TC, TK, and TP, the species did not form distinct classes, suggesting overlapping nutritional strategies and environmental adaptations. Furthermore, spatial autocorrelation analysis indicates strong positive correlations for DBH, TC, and TP, whereas TK and TN correlations are non-significant. The results suggest habitat filtering as a key driver in intraspecific relationships, with a finer spatial scale of ecological niche division through TC and TP, which is crucial for maintaining coexistence among these oak species.

Assessing Leaf Morphometric Symmetry of Four Chinese Quercus Species in a Mixed Forest

(1) Background: Oaks have achieved notoriety for sufficient levels of sympatric species richness allowing hybridization, thus generating substantial phenotypic variation. Leaf fluctuation asymmetry is an important attribute, as it reflects not only genetic variability but also species buffering capacity. (2) Methods: We investigated the phenotypic diversity of four-oak species (Quercus acutissima, Q. variabilis, Q. fabri, and Q. serrata var. brevipetiolata) using leaf geometric morphometric analysis. Eight leaf morphological indicators (length, width, perimeter, area, left and right areas, areal ratio, and normalized symmetry index) were used to determine the hybridization level, whereas bilateral symmetry indicators were used to assess species environmental adaptation; (3) Results: Phenotypic variation ranged from 1.54 to 29.35 folds and significantly diverged among the studied species. Taxonomically species in Section Quercus (Q. fabri and Q. serrata var. brevipetiolata) are lower than those in Section Cerris (Q. acutissima and Q. variabilis) with good bilateral symmetry. The bilateral symmetry index of Q. variabilis had a larger range of variation, indicating better environmental adaptability; (4) Conclusions: We presume that species in Section Quercus with less leaf fluctuation asymmetry have a high level of genetic heterozygosity; however, this assumption requires further verification. The observed phenotypic diversity reflects a combination of environmental and genetic factors.

FIRST RECORD OF TINOCALLIS ZELKOWAE (TAKAHASHI, 1919) (HEMIPTERA APHIDIDAE CALAPHIDINAE) IN THE IBERIAN PENINSULA

The East-Asian aphid Tinocallis (Tinocallis) zelkowae is recorded for the first time in the Iberian Peninsula on Zelkova serrata (Ulmaceae) in the Viveros Gardens of the city of Valencia (Spain). This is the second record of the species in Europe, after being cited on a Japanese zelkova bonsai in England in 1974. Alate viviparous females and sexuales (winged males and apterous oviparae) are here described, and we present the molecular sequence of the mitochondrial cytochrome oxidase I, which allows comparison with the recently described T. (T.) latifoliae on in Zelkova serrata var. latifolia. It is the fifth species of Tinocallis genus that is known in territories of Iberian Peninsula, three of which are also native to Southeast Asia. KEY WORDS: aphids, biological invasion, Zelkova serrata, Spain

Inter- and intra-specific phenotypic variation of ecological stoichiometric traits in a mixed-oak secondary forest in China

Ecological stoichiometry provides a framework for the balance and flow of elements between organisms and ecosystems. Elemental phenotypes have an important influence on the environmental adaptation and ecological evolution of plants. There have been few reports on inter- and intra-specific phenotypic variations of ecological stoichiometric traits for congeneric species in a mixed forest although such variations are well- documented at the species level at global, regional and local scales. In this study, total carbon (TC), nitrogen (TN), phosphorus (TP) and potassium (TK) were measured in leaves and the elemental phenotypes were statistically analyzed in four species of oaks—Quercus fabri, Q. serrata var. glandulifera, Q. acutissima and Q. variabilis—in a mixed-oak secondary forest in Yushan, Jiangsu, China. The average element concentrations in the four oak species were not relatively higher than previously reported for oaks from world and Chinese flora. Ecological stoichiometry traits were correlated with tree height and diameter at breast height, indicating that phosphorous and potassium were positively correlated with tree size, while carbon was negatively correlated, especially the relationship between oak growth and total carbon or total phosphorus was obvious, and the study concluded that this was because plant growth depended on phosphorus storage and had opposite effects on leaf carbon accumulation. Based on tree plasticity index and the coefficient of variation, there was medium variation in element concentrations. The plasticity index of total carbon levels was the lowest, and that of potassium the highest. Principal component analysis and cluster analysis showed that the intra-specific variation among the four oak species was higher than inter-specific variation. From the perspective of nutrient supply and ecological adaptation, this study creates a foundation for the management of secondary oak forest stands.

Sympatric genome size variation and hybridization of four oak species as determined by flow cytometry genome size variation and hybridization.

The Quercus species serve as a powerful model for studying introgression in relation to species boundaries and adaptive processes. Coexistence of distant relatives, or lack of coexistence of closely relative oak species, introgression may play a role. In the current study, four closely related oak species were found in Zijinshan, China. We generated a comprehensive genome size (GS) database for 120 individuals of four species using flow cytometry‐based approaches. We examined GS variability within and among the species and hybridization events among the four species. The mean GSs of Q. acutissima, Q. variabilis, Q. fabri, and Q. serrata var. brevipetiolata were estimated to be 1.87, 1.92, 1.97, and 1.97 pg, respectively. The intraspecific and interspecific variations of GS observed among the four oak species indicated adaptation to the environment. Hybridization occurred both within and between the sections. A hybrid offspring was produced from Q. fabri and Q. variabilis, which belonged to different sections. The GS evolutionary pattern for hybrid species was expansion. Hybridization between the sections may be affected by habitat disturbance. This study increases our understanding of the evolution of GS in Quercus and will help establish guidelines for the ecological protection of oak trees.

Comparative analysis of the complete chloroplast genomes of six white oaks with high ecological amplitude in China

Quercus L. has significant societal, ecological and economic benefits in the Northern Hemisphere. However, species identification among oaks is notoriously difficult. China harbours highly diverse oaks, of which the diversity of white oaks is the most extensive; however, to date, the evolution of chloroplast (cp) genomes in white oaks in China has not been comprehensively studied. Thus, we sequenced the complete cp genomes (161,254 bp, 161,229 bp and 161,254 bp in size) of three white oak species (Quercus serrata Thunb. var. brevipetiolata A. DC. Nakai, Quercus wutaishansea Mary and Quercus mongolica Fischer ex Ledebour, respectively). Six white oak species (Quercus aliena Blume, Quercus dentata Thunb., Quercus aliena Blume var. acutiserrata Maximowicz ex Wenzig, Q. serrata var. brevipetiolata, Q. wutaishanica and Q. mongolica) and five other Fagaceae species (Quercus rubra L., Quercus variabilis Bl., Quercus aquifolioides Rehd. et Wils., Fagus engleriana Seem. and Castanea henryi Skan Rehd. et Wils.) were retrieved for comparative analyses. We detected 11 highly divergent regions (psbA, matK/rps16, rps16, trnS-GCU/trnG-GCC, trnR-UCU/atpA, trnT-GGU/psbD, ndhJ, ndhJ/ndhK, accD, ndhF and ycfI) through comparative analyses and these regions might be used as molecular markers. The ω ratio of the rps12, rpoC2 and ycf1 genes was greater than 1 in several comparison groups between white oaks and the petA gene was subjected to significant positive selection between the comparison of six white oaks and Q. variabilis. Phylogenetic analyses revealed that six white oaks were grouped with Q. rubra, forming a single clade.

Jasmonates from Chinese acorns (Quercus serrata var. brevipetiolata) exert pronounced anti-neuroinflammatory activities

Chinese oak (Quercus serrata var. brevipetiolata) belongs to the genus Quercus in Fagaceae family. Its seed, called as Chinese acorn, has been served as a traditional medicine and foodstuff in China. In this study, ten jasmonates were isolated and purified from Chinese acorn, including five new (1–5) and five known jasmonates (6–10). The new jasmonates were identified as butyl (1R,2R)-2-[(2′Z)-5′-hydroxy-penten-2′-enyl]-3-oxo-cyclopentane acetate (1), methyl {2-[4′-(β-d-glucopyranosyloxy)-pentyl}-3-oxo-cyclopentane acetate (2), methyl {(1R,2R)-2-[(2′Z,4′R)-4′-(β-d-glucopyransyloxy)-pent-2′-enyl]}-3-oxo-cyclopentane acetate (3), methyl {(1R,2R)-2-[(2′E,4′S)-4′-(β-d-glucopyransyloxy)-pent-2′-enyl]}-3-oxo-cyclopentane acetate (4), and methyl {(1R,2R)-2-[(2′S,3′E)-2′-(β-D-glucopyransyloxy)-pent-3′-enyl]}-3-oxo-cyclopentane acetate (5), respectively. The isolated jasmonates were evaluated for anti-neuroinflammatory activity, and some showed pronounced inhibitory effects on the production of nitric oxide (NO) induced by lipopolysaccharide (LPS) in BV-2 microglia cells. Some jasmonates could dose-dependently reduce the expression of LPS-induced pro-inflammatory factors (iNOS and COX-2) and could block NF-κB nuclear translocation. This study suggested that Chinese acorns could be served as a healthy product for neuroinflammatory related diseases, such as Alzheimer’s disease.

Species delimitation in the East Asian species of the relict tree genus Zelkova (Ulmaceae): A complex history of diversification and admixture among species

Zelkova species, trees of the elm family (Ulmaceae), are part of the Cenozoic relict flora. In western Eurasia, the genus comprises three species that are restricted to disjunct areas (Z. sicula on Sicily, Z. abelicea on Crete and Z. carpinifolia in Transcaucasia). The situation is different in East Asia, where three species (Z. serrata, Z. schneideriana and Z. sinica) have at least partly overlapping distributions. The phylogenetic and phylogeographic status of these East Asian species is still not well understood, mainly since all previous studies used almost exclusively plant material collected in botanical gardens and were based on very small numbers of individuals. Our study is the first based on 33 natural populations covering all important areas with Zelkova species in the Sino-Japanese Floristic Region. Chloroplast and microsatellite markers were used, and Bayesian analyses were run for both types of markers. East Asian Zelkova species cluster into two groups that partially overlap when comparing the two types of markers. For chloroplast markers, the two groups coincide with all Japanese, some Korean and northern Chinese Z. serrata in one group and all other individuals in the other group, regardless of whether they are attributed to Z. serrata, Z. sinica or Z. schneideriana from Korea, mainland China and Taiwan. At the nuclear level, however, the clustering clearly groups all the Z. serrata individuals together, regardless of whether they are from Japan, Korea or China, and the two other species in a second group. This complex genetic pattern in East Asian Zelkova species is most likely due to a combination of ancient diversification and speciation events and more recent hybridization during the last glacial/interglacial retractions and recolonizations. One of the surprising results of our study concerns the populations from Taiwan, which are genetically similar to Z. schneideriana. Thus, their assignation to a separate taxon (Z. tarokoensis) or to a variety of Z. serrata (Z. serrata var. tarokoensis), as currently reported in all local and national floras, might be in need of revision. Furthermore, our results indicate that the East Asian species are more closely related to Z. carpinifolia than to any other Western European species. Haplotypes of Z. sicula and Z. abelicea (Mediterranean region) as well as those of Z. sinica and Z. schneideriana (East Asia) seem to have diversified more recently. The most ancient haplotypes are found among the western Eurasian Z. carpinifolia and the East Asian Z. serrata. This result is in agreement with the carpinifolia and serrata-like morphotypes commonly found in the fossil record.

Triterpenes isolated from acorns of Quercus serrata var. brevipetiolata exert anti-inflammatory activity

Acorns serve as an important role as an important cash crop in human history and are a source of food for many countries. In this study, ten pentacyclic triterpenes, three of which were novel, were isolated from acorns (Quercus serrata var. brevipetiolata). The structures of novel triterpenoids were established based on the interpretation of chemical and spectroscopic analyses, including IR, HR-ESI⿿MS, and NMR experiments (1D and 2D NMR), which were elucidated to be 3,23-O-methyl butyrate-2α,3β,19α,23-tetrahydroxy-urs-12-en-28-oic acid β-d-glucopyranosyl ester (1), 3,23-O-methyl butyrate-2α,3β,19α,23-tetrahydroxy-olean-12-en-28-oic acid β-d-glucopyranosyl ester (2), and 23-acetoxy-2α,3β,19α-trihydroxyurs-12-en-28-oic acid (3), respectively. All isolated compounds were tested for their inhibitory effects on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages. Most of the triterpenes from acorns showed pronounced anti-inflammatory activities compared to positive control indomethacin. Furthermore, based on the results of the nitric oxide assay, production of pro-inflammatory markers including interleukin-6 (IL-6) and interleukin-8 (IL-8) of compound 1⿿3 in TNF-α stimulated RAW 264.7 were investigated by ELISA, which showed these pentacyclic triterpenes may be responsible with the two pro-inflammatory cytokines for the anti-inflammatory activity of acorn.

Anti-Inflammatory Oleanolic Triterpenes from Chinese Acorns.

Acorns play an important role in human history and are a source of food and recipes for many cultures around the world. In this study, eleven oleanolic triterpenes, one of which was novel, were isolated from Chinese acorns (Quercus serrata var. brevipetiolata). The chemical structure of the novel triterpene, which was identified as 2α,3β,19α-trihydroxy-24-oxo-olean-12-en-28-oic acid (1), was established based on the interpretation of chemical and spectroscopic analyses, including IR, HR-ESI-MS, and NMR experiments (1H, 13C NMR, DEPT, 1H-1H COSY, HSQC, HMBC, and NOESY). All isolated compounds were tested for their inhibitory effects on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages. Compared with the positive control drug indomethacin (IC50 = 47.4 μM), compounds 1, 3, 6 and 8 exhibited remarkable anti-inflammatory activities with IC50 values of 5.4, 7.8, 4.0 and 8.9 μM, respectively. Besides, compounds 2, 4, 7 and 9 also showed moderate anti-inflammatory activities with IC50 values of 10.1, 13.0, 20.1 and 17.2 μM, respectively. Furthermore, Compound 1 could inhibit TNF-α-induced IL-6 and IL-8 production in MH7A cells.

Inter- and intra-specific variation in stemflow for evergreen species and deciduous tree species in a subtropical forest

Quantification of stemflow is necessary for the assessment of forest ecosystem hydrological effects. Nevertheless, variation of stemflow among plant functional groups is currently not well understood. Stemflow production of co-occurring evergreen broadleaved trees (Cyclobalanopsis multinervis and Cyclobalanopsis oxyodon) and deciduous broadleaved trees (Fagus engleriana and Quercus serrata var. brevipetiolata) was quantified through field observations in a mixed evergreen and deciduous broadleaved forest. The research results revealed that stemflow increased linearly with increasing rainfall magnitude, with precipitation depths of 6.9, 7.2, 10.0 and 14.8 mm required for the initiation of stemflow for C. multinervis, C. oxyodon, F. engleriana and Q. serrata, respectively. Stemflow percentage and funneling ratio (FR) increased with increasing rainfall in a logarithmic fashion. Stemflow percentage and FR tended to grow rapidly with increasing rainfall magnitude up to a rainfall threshold of 50 mm, above which, further rainfall increases brought about only small increases. For C. multinervis, C. oxyodon, F. engleriana and Q. serrata, FR averaged 19.8, 14.8, 8.9 and 2.8, respectively. The stemflow generating rainfall thresholds for evergreen species were smaller than for deciduous species. Furthermore, stemflow percentage and FR of the former was greater than the latter. For both evergreen species and deciduous species, overall funneling ratio (FRs) decreased with increasing basal area. We concluded that: (1) although stemflow partitioning represented a fairly low percentage of gross rainfall in mixed evergreen and deciduous broadleaved forests, it was capable of providing substantial amount of rainwater to tree boles; (2) the evergreen species were more likely to generate stemflow than deciduous species, and directed more intercepted rainwater to the root zone; (3) small trees were more productive in funneling stemflow than larger trees, which may provide a favorable condition for the survival and growth of small trees when competing with larger trees.

Analysis on Growth Characteristics of Landscape Trees in Apartment Complex

The purpose of this study is to offer the raw data for improving the method of landscape planting in apartment complex by objective surveying and analysing the growth ratio by type and ground planted in landscape tree. The results are as follows. In the survival ratio of tree, Pinus densiflora was the highest and Abies koreana was the lowest in evergreen tree. In case of deciduous tree, the species of the highest survival ratio were Diospyros kaki, Zelkova serrata, Prunus mume, Lagerstroemia indica and Ginkgo biloba. There showed that Sorbus commixta and Chaenomeles sinensis had the lowest survial ratio. In case of tree growth by types, Pinus strobus was the highest and Pinus densiflora var. globosa was the lowest among evergreen trees. Among deciduous trees, the growth ratio of Zelkova serrata was the highest, and the trees showed the lowest growth were Lagerstroemia indica, Magnolia denudata and Cornus officinalis. Pinus strobus, Cornus kousa, Ginkgo biloba, Chionanthus retusa and Acer palmatum were good growth in natural ground, and Zelkova serrata and Prunus armeniaca var. ansu were good in artificial ground. In the future, if you study the growth characteristics and shrubs that are excluded from the study of landscape trees in various locations are expected to derive objective data.

Context-dependent seed dispersal determines acorn survival of sympatric oak species

Seed traits play an important role in seed dispersal and possibly in eventual plant community structure and dynamics. Though seed traits have been shown to influence seed dispersal of one given tree species, it is not clear if and how seed dispersal and seed survival of one tree species are affected by neighboring tree species at inter-specific level. In the present study, we investigated acorn dispersal of two oak species Q. variabilis (bearing large acorn) and Q. serrata var. brevipetiolata (bearing small acorn) in the presence of sympatric Q. aliena acorns (medium size), to test the ‘context-dependent’ hypothesis, which states that seed dispersal patterns of one tree species can be affected by sympatric tree species at inter-specific level. Our results showed that the probability of acorn removal of Q. variabilis was higher in the presence of Q. aliena acorns. However, the presence of Q. aliena acorns significantly decreased acorn removal rates of Q. serrata var. brevipetiolata. Acorns of Q. serrata var. brevipetiolata were less likely to be cached by small rodents in the presence of Q. aliena acorns, whereas, acorns of Q. variabilis tended to be scatter-hoarded in the presence of Q. aliena acorns. The presence of Q. aliena acorns promoted Q. variabilis acorns to establish seedlings, but arrested seed-seedling transition in Q. serrata var. brevipetiolata. Our study verifies the interspecific interactions of seed dispersal systems of sympatric oak species, showing the ‘context-dependent’ hypothesis that seed dispersal of one given tree species can be regulated by another or more sympatric tree species bearing seeds with contrasting traits.

Notes on powdery mildews (Erysiphales) in Japan: II. Erysiphe sect. Microsphaera

Several novelties of powdery mildews in Japan are reported, including the first Japanese collection of the teleomorph of Erysiphe platani on Platanus × acerifolia, the first description of ascomata of E. viburni on Viburnum sieboldii var. obovatifolium, and the first morphological descriptions and molecular data for E. wallrothii on Leucothoë grayana and Pseudoidium hortensiae on Hydrangea serrata var. megacarpa based on Japanese specimens.

Incorporating Cache Management Behavior into Seed Dispersal: The Effect of Pericarp Removal on Acorn Germination

Selecting seeds for long-term storage is a key factor for food hoarding animals. Siberian chipmunks (Tamias sibiricus) remove the pericarp and scatter hoard sound acorns of Quercus mongolica over those that are insect-infested to maximize returns from caches. We have no knowledge of whether these chipmunks remove the pericarp from acorns of other species of oaks and if this behavior benefits seedling establishment. In this study, we tested whether Siberian chipmunks engage in this behavior with acorns of three other Chinese oak species, Q. variabilis, Q. aliena and Q. serrata var. brevipetiolata, and how the dispersal and germination of these acorns are affected. Our results show that when chipmunks were provided with sound and infested acorns of Quercus variabilis, Q. aliena and Q. serrata var. brevipetiolata, the two types were equally harvested and dispersed. This preference suggests that Siberian chipmunks are incapable of distinguishing between sound and insect-infested acorns. However, Siberian chipmunks removed the pericarp from acorns of these three oak species prior to dispersing and caching them. Consequently, significantly more sound acorns were scatter hoarded and more infested acorns were immediately consumed. Additionally, indoor germination experiments showed that pericarp removal by chipmunks promoted acorn germination while artificial removal showed no significant effect. Our results show that pericarp removal allows Siberian chipmunks to effectively discriminate against insect-infested acorns and may represent an adaptive behavior for cache management. Because of the germination patterns of pericarp-removed acorns, we argue that the foraging behavior of Siberian chipmunks could have potential impacts on the dispersal and germination of acorns from various oak species.

New Species, Combinations, and Lectotypifications in Neotropical and Northern MexicanFrangula(Rhamnaceae)

In preparing the family Rhamnaceae for an upcoming volume of Flora Mesoamericana, it became apparent, based on recent molecular work (Bolmgren & Oxelman, 2004; Bolmgren, pers. comm., 2013), as well as historical (Grubov, 1949; Kartesz & Gandhi, 1994), and personal morphological studies, that recognization of the genus Frangula Mill. is well supported. The emphasis of the current study has been on Mesoamerican species and four species from Mesoamerica, F. circumscissa A. Pool from Costa Rica, F. darienensis A. Pool from Panama, F. grandiflora A. Pool described from Honduras and also found in Chiapas, Mexico, F. pendula A. Pool described from Costa Rica and also found in Panama, and one species from Oaxaca, Mexico, F. inconspicua A. Pool, are published here as new. Four Mesoamerican species and two varieties published in Rhamnus L. are transferred to Frangula as: F. breedlovei (L. A. Johnst. & M. C. Johnst.) A. Pool [≡ R. breedlovei L. A. Johnst. & M. C. Johnst.], F. mcvaughii (L. A. Johnst. & M. C. Johnst.) A. Pool [≡ R. mcvaughii L. A. Johnst. & M. C. Johnst.], F. oreodendron (L. O. Williams) A. Pool [≡ R. oreodendron L. O. Williams], F. wendtii (Ishiki) A. Pool [≡ R. wendtii Ishiki], F. capreifolia var. grandifolia (M. C. Johnst. & L. A. Johnst.) A. Pool [≡ R. capreifolia var. grandifolia M. C. Johnst. & L. A. Johnst.], and F. discolor var. mesoamericana (L. A. Johnst. & M. C. Johnst.) A. Pool [≡ R. sphaerosperma var. mesoamericana L. A. Johnst. & M. C. Johnst.]. The following new combinations are made for five Mexican species north of the Flora Mesoamericana area: F. chimalapensis (R. Fernández) A. Pool [≡ R. chimalapensis R. Fernández], F. hintonii (M. C. Johnst. & L. A. Johnst.) A. Pool [≡ R. hintonii M. C. Johnst. & L. A. Johnst.], F. longistyla (C. B. Wolf) A. Pool [≡ R. longistyla C. B. Wolf], F. scopulorum (M. E. Jones) A. Pool [≡ R. serrata var. scopulorum M. E. Jones], and F. surotatensis (Gentry) A. Pool [≡ R. surotatensis Gentry]. Four South American species are transferred: F. acuminata (Maguire & Steyerm.) A. Pool [≡ R. acuminata Maguire & Steyerm.], F. chimantensis (Steyerm. & Maguire) A. Pool [≡ R. chimantensis Steyerm. & Maguire], F. marahuacensis (Steyerm. & Maguire) A. Pool [≡ R. marahuacensis Steyerm. & Maguire], F. neblinensis (Maguire & Steyerm.) A. Pool [≡ R. neblinensis Maguire & Steyerm.]. Rhamnus sphaerosperma var. longipes M. C. Johnst. & L. A. Johnst. (from Hispaniola and Puerto Rico) is transferred to Frangula and raised to the rank of species, necessitating the publication of the new name F. longipedicellata A. Pool. Lectotypes are designated for F. polymorpha Reissek, R. citrifolia Rusby, and R. riojae Perkins.

Tree morphology responds to neighbourhood competition and slope in species-rich forests of subtropical China

Trees are able to respond to their local biotic and abiotic environment with morphological adjustments which improve resource acquisition and, thus, growth. In forests, light is broadly recognised as one of the major factors determining growth, and morphological responses comprise changes in crown architecture and stem stature. On sloping terrain, the interplay of phototropism and gravitropism may further affect morphological growth characteristics. However, different tree species are expected to show species-specific responses. In this study, we analysed three growth characteristics of tree individuals belonging to four species of two functional groups (evergreen: Schima superba, Castanopsis eyrei, deciduous: Quercus serrata var. brevipetiolata, Castanea henryi) in a species-rich Chinese subtropical forest. Crown projection area, relative crown displacement and stem inclination were related to biotic (local species richness, functional richness, competition, stand age) and abiotic (slope aspect and inclination, soil depth) variables in the local neighbourhood of the tree individuals. We hypothesised that (i) there are species-specific differences in the morphological response of crown architecture and stem stature and (ii) that crown size and asymmetry as well as stem inclination are influenced by both, biotic and abiotic factors. In contrast to our expectations we were unable to reveal any species-specific differences in any of the three growth characteristics. The results of mixed effects models showed that crown area was mainly affected by the target tree's dbh and biotic variables related to neighbours (competition, functional diversity), whereas stem inclination was mainly influenced by slope. Relative crown displacement was influenced by both, biotic and abiotic variables. We conclude that growth responses resulting in crown displacement and stem inclination seem to be an important mechanism to ameliorate foraging for light in our study area, but that these responses appear to be species-independent. The interplay of stem inclination and crown displacement allows for a plastic response of tree individuals in biotically and abiotically heterogeneous environments. Our results indicate that forest management in this region should focus on functionally diverse stands which are promoting crown area positively resulting in increased growth rates of individual trees.

Frequency-dependent selection by tree squirrels: adaptive escape of nondormant white oaks

Frequency-dependent selection is theoretically predicted to have an important impact on predator–prey dynamics, but little is understood about this process in nature. We investigated oak–squirrel interactions to test the hypothesis that tree squirrels predate/disperse white oak acorns based on the frequency of their germination phenotypes (dormancy, i.e., delayed germination vs. nondormancy, i.e., immediately germinating), which in turn influences dispersal and establishment of these oaks. In Central China, we manipulated the relative frequency of dormant and nondormant acorns available to Père David's Rock squirrel (Sciurotamias davidianus) with 2 white oaks (QAA, Quercus aliena var. acutesevata and QSB, Quercus serrata var. breviptiolata) that exhibit considerable variation in acorn germination between and within oak species throughout the fruiting season. We predicted that dispersal success (i.e., the probability of a viable acorn being hoarded) of each germination phenotype would vary with the phenotype frequency and hence show either positive or negative frequency-dependent selection. We found that acorn-embryo removal by squirrels may select for the dormant phenotype but is more likely to occur for early germinating acorns. We also found that both absolute and relative dispersal success of each germination phenotype increased with their frequency in the 2 white oaks, thus demonstrating positive frequency-dependent selection. Our results reveal that the frequency of germination phenotypes can account for as much as 40.5% and 21.4% of the observed dispersal success in QAA and QSB, respectively. We show that behavioral preferences of scatter-hoarding animals could result in frequency-dependent selection in nature, and such selection may help maintain variation in germination phenotypes in prey species.

BANZARE holothuroids (Echinodermata: Holothuroidea)

The holothuroid species collected by The British, Australian and New Zealand Antarctic Research Expedition (BANZARE) are listed, with some systematic annotations. A previous report by O’Loughlin on some BANZARE holothuroids is revised and incorporated. Four new species are described: the Antarctic dactylochirotid Echinocucumis kirrilyae sp. nov.; the Kerguelen dendrochirotid Clarkiella deichmannae sp. nov.; the Antarctic dendrochirotids Trachythyone cynthiae sp. nov. and Trachythyone mackenzieae sp. nov. Cucumaria serrata var. intermedia Théel from Heard and Kerguelen, and Cucumaria serrata var. marionensis Théel from Marion, are raised to species status, and assigned to Pseudocnus Panning. Cucumaria (Semperia) ekmani Ludwig & Heding is a junior synonym of Cucumaria kerguelensis Théel. Cucumaria kerguelensis is re-assigned to Neopsolidium Pawson. Thyone recurvata Théel and Cucumaria squamata Ludwig are junior synonyms of Trachythyone muricata Studer. Cucumaria (Semperia) bouvetensis Ludwig & Heding is formally re-assigned to Trachythyone. Trachythyone baja Hernández is a junior synonym of Trachythyone bouvetensis (Ludwig & Heding). Molecular genetic data indicate possible allopatric cryptic Antarctic forms for the morpho-species Laetmogone wyvillethomsoni Théel. A table with all species and station data is provided.