Branching Intensity Research Articles

Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest.

The identification of plant functional traits that can be linked to ecosystem processes is of wide interest, especially for predicting vegetational responses to climate change. Root diameter of the finest absorptive roots may be one plant trait that has wide significance. Do species with relatively thick absorptive roots forage in nutrient-rich patches differently from species with relatively fine absorptive roots? We measured traits related to nutrient foraging (root morphology and architecture, root proliferation, and mycorrhizal colonization) across six coexisting arbuscular mycorrhizal (AM) temperate tree species with and without nutrient addition. Root traits such as root diameter and specific root length were highly correlated with root branching intensity, with thin-root species having higher branching intensity than thick-root species. In both fertilized and unfertilized soil, species with thin absorptive roots and high branching intensity showed much greater root length and mass proliferation but lower mycorrhizal colonization than species with thick absorptive roots. Across all species, fertilization led to increased root proliferation and reduced mycorrhizal colonization. These results suggest that thin-root species forage more by root proliferation, whereas thick-root species forage more by mycorrhizal fungi. In mineral nutrient-rich patches, AM trees seem to forage more by proliferating roots than by mycorrhizal fungi.

Transplanting and harvesting effect on artemisinin biosynthesis and herb yield in Artemisia annua L.

This study evaluates the effect of differential transplantation (5th January, 28th January and 20th February; Ist T, IInd T and IIIrd T, respectively) and harvesting time (after 100 days of transplantation and 126–204 days of age) on artemisinin and herb yield in Artemisia annua in order to optimize field conditions. During the investigation, maximum plant height with branching intensity was observed in the third transplantation. Such a pattern of morphological appearance is classified under oval canopy, and such traits can be useful as visible morphotypic markers. Maximum plants with high artemisinin content were observed in the IInd transplantation. Interestingly, a wide range of artemisinin content (0.1–1 %) was observed in all three populations. Hence, to achieve maximum growth and high artemisinin yield within the shortest possible time, the second transplantation date is recommended for large-scale cultivation.

Using root form to improve our understanding of root function.

Using root form to improve our understanding of root function.

Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies.

Root traits vary enormously among plant species but we have little understanding of how this variation affects their functioning. Of central interest is how root traits are related to plant resource acquisition strategies from soil. We examined root traits of 33 woody species from northeastern US forests that form two of the most common types of mutualisms with fungi, arbuscular mycorrhizas (AM) and ectomycorrhizas (EM). We examined root trait distribution with respect to plant phylogeny, quantifying the phylogenetic signal (K statistic) in fine root morphology and architecture, and used phylogenetically independent contrasts (PICs) to test whether taxa forming different mycorrhizal associations had different root traits. We found a pattern of species forming roots with thinner diameters as species diversified across time. Given moderate phylogenetic signals (K = 0.44–0.68), we used PICs to examine traits variation among taxa forming AM or EM, revealing that hosts of AM were associated with lower branching intensity (rPIC = −0.77) and thicker root diameter (rPIC = −0.41). Because EM evolved relatively more recently and intermittently across plant phylogenies, significant differences in root traits and colonization between plants forming AM and EM imply linkages between the evolution of these biotic interactions and root traits and suggest a history of selection pressures, with trade-offs for supporting different types of associations. Finally, across plant hosts of both EM and AM, species with thinner root diameters and longer specific root length (SRL) had less colonization (rPIC = 0.85, −0.87), suggesting constraints on colonization linked to the evolution of root morphology.

Leading dimensions in absorptive root trait variation across 96 subtropical forest species.

Absorptive root traits show remarkable cross-species variation, but major root trait dimensions across species have not been defined. We sampled first-order roots and measured 14 root traits for 96 angiosperm woody species from subtropical China, including root diameter, specific root length, stele diameter, cortex thickness, root vessel size and density, mycorrhizal colonization rate, root branching intensity, tissue density, and concentrations of carbon and nitrogen ([N]). Root traits differed in the degree of variation and phylogenetic conservatism, but showed predictable patterns of cross-trait coordination. Root diameter, cortex thickness and stele diameter displayed high variation across species (coefficient of variation (CV)=0.51-0.69), whereas the stele:root diameter ratio and [N] showed low variation (CV<0.32). Root diameter, cortex thickness and stele diameter showed a strong phylogenetic signal across species, whereas root branching traits did not, and these two sets of traits were segregated onto two nearly orthogonal (independent) principal component analysis (PCA) axes. Two major dimensions of root trait variation were found: a diameter-related dimension potentially integrating root construction, maintenance, and persistence with mycorrhizal colonization, and a branching architecture dimension expressing root plastic responses to the environment. These two dimensions may offer a promising path for better understanding root trait economics and root ecological strategies world-wide.

Bank branch location and stability during distress

Purpose – The purpose of this paper is to examine the impact of bank branch location on the likelihood of bank failure during the most recent financial crisis. Design/methodology/approach – This paper estimates the probit regression to identify the causes of bank failures and attempts to determine the role of branch location in bank performance. Findings – Using data from failed and surviving banks in Georgia and Florida, this paper finds that diversifying the balance sheet and operating in more competitive markets reduced failure rates, but branching intensity, measured by number of branches and distance of branches from the home office did not significantly reduce the probability of failure. This suggests that, at least in today ' s market, it is not important to bank stability to have a branching network a significant distance from the home office. Originality/value – This paper carefully considers the role of branch location in the likelihood of bank failure during financial distress. As such, it contributes to the historical policy debate regarding regulation prohibiting or minimizing banks ' ability to branch. It also contributes to our understanding of how banks structure their branching networks in the contemporary banking environment.

竹类植物对异质生境的适应：表型可塑性

Since heterogeneity is ubiquitous,plant phenotypic plasticity is a vital ecological countermeasure to adapt to the heterogeneous habitat. Owing to the double modularity,the clonal plant has higher phenotypic plasticity and then acquires higher adaptability than other plants. Bamboo is a group of clonal plants,and mainly composed of woody plants. Bamboo could grow well in the difficult site and heterogeneous habitat where most plants hardly survive. Meanwhile,bamboo can expand rapidly to broad-leaved forest in the bamboo-forest ecotone. Compared with most plants,bamboo has stronger adaptability to heterogenous habitat due to its higher phenotypic plasticity. Thus,in order to advance the development of bamboo ecology, it is necessary to systematically summarize the bamboo phenotypic plasticity and adaptation countermeasures to heterogeneous habitat. Literature analysis shows that bamboo has obvious phenotypic plasticity to respond to heterogeneous habitat. Four realizing ways of phenotypic plasticity including morphological plasticity, selective placement,clonal integration and intraclonal division of labor,are exerted by bamboo to cope with heterogeneous habitat.Firstly,bamboo modifies the morphology,such as height,diameter,leaf area,spacer length,node number,branching angle,biomass etc,to adapt to the changes of above-ground or under-ground resources. The morphological modification is adapted to the resource level. In the poor resource habitat,energy is mainly invested in the constructing of absorbingstructures in order to increase resource absorption. In contrast,most energy is invested in the growth of ramet to increase plant biomass in the rich resource habitat. Secondly,bamboo grows more ramets in the fertile microhabitat than that of in the infertile microhabitat. Thus,bamboo can acquire more survival resources and adapt to the unfavorable habitat. The selective placement is achieved by altering the spacer length,branching angle and branching intensity. Clearly,it is an active behavior to adapt to the heterogeneous habitat. Thirdly,clonal integration behavior helps bamboo ramets in unfertile habitat gain resource from those in fertile habitat. Actually,bamboo shoot growth is a typical process of clonal integration,because the new shoot need obtain the nutrients from mother ramets. However,the direction and intensity of clonal integration could be altered with the variation of resource distribution in the heterogeneous habitat. Fourthly,intraclonal division of labor is another important countermeasure to deal with the heterogeneous habitat. Clonal integration and specialization of ramet are two basic prerequisites for intraclonal division of labor. Although many studies of intraclonal division of labor were developed in herbaceous plants,little is known about that in bamboo. Therefore,we need further confirm whether the intraclonal division of labor is commonly used by bamboo. Overall,the present studies focus on modular morphology and biomass allocation pattern,while little attention is paid on the mechanism of phenotypic plasticity. In the future,the researches on bamboo phenotypic plasticity shall be focused on the following 5 aspects: 1) pattern and mechanism of clonal integration;2) influence of clonal integration on ecosystem stability; 3) mechanism of intraclonal division of labor,and its relationship with environment; 4) hierarchical selection of phenotypic plasticity and the environmental effect; 5) differences of phenotypic plasticity in different types of clonal architecture,and their mechanisms.

Experimentally reduced root-microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus.

Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10-20 %) and increased specific root length (approx. 10-30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root trait variation, interactions with symbionts and recent progress in standardization of methods for quantifying root traits.

Mapping Forest Regeneration from Terrestrial Laser Scans

Abstract Location, spread, abundance and density of forest regeneration are key factors in understanding forest dynamics as well as in operational management of uneven-aged stands. Simulation of forest growth, silviculture and planning of skid road networks require accurate and objective methods for locating forest regeneration. Terrestrial laser scanning has high potential for tree mapping, however, the development of automatic processing methods has been focused on mature trees so far. This study introduces an automatic procedure to locate individual trees with 3-6 meter height from terrestrial laser scanner data. The method has been validated on three sample quadrates representing different stand structures and it succeeded in detecting 79-90% of trees extracted manually from the point cloud. Out of the investigated stand features, stem density had the strongest impact on the performance, while branching intensity slightly affected the detection rate. The results highlight that terrestrial laser scanning has the ability for the quantitative evaluation of regeneration, providing a prospective tool for surveying forests of contiguous cover.

Development of root morphology traits of the Czech lucerne varieties in chernozem over a three year period

The root system of plants is generally in relation to important agronomic and ecological characteristics. The aim of this study was to investigate differences in root morphology development of Czech lucerne varieties under chernozem soil conditions. In spring 2007, a field experiment with ten Czech lucerne varieties was established with a regular space of 125 mm between the rows. During the 2008–2010 period, the plants were sampled every autumn after the last cut in five blocks per each variety; the size of the sampling area was 50 × 50 cm and average depth of sampling was 0.25 m. All varieties provided similar trend in root morphology development but some differences could be detected in the rate of this development. From all evaluated root traits, these differences were connected mainly with tap-root diameter, intensity of root branching and lateral root number. Advisable varieties should provide higher density of plant together with higher root diameter and branching which is resulted to higher root weight per m2 and consequently to higher stand productivity. The root-branched plants achieved a significantly higher tap-root diameter of 10.7 mm in comparison with unbranched-root plants with 7.1 mm. Except of plant age, the stand density and tap-root diameter could be considered as a parameter to drive lucerne root morphology development. Within a year, the increase of tap-root diameter was connected with increase of root branching at root-branched plants whilst decrease of plant density caused the beginning of the process of root branching at tap-rooted plants. The range of root traits influenced themselves so their joint presentation is advisable. It must be remembered that soil conditions are a factor which strongly modified the root morphology traits; therefore, these results must be completed with other experiments under various soil conditions. The knowledge of root morphology traits could contribute to the assessment of lucerne varieties specific features.

Growth responses of a rhizomatous herb &lt;I&gt;Bolboschoenus planiculmis&lt;/I&gt; to scale and con-trast of soil nutrient heterogeneity

Aims Spatial heterogeneity in soil nutrients is common in nature, and clonal plants are supposed to be able to better use spatially heterogeneously distributed soil nutrients. Although scale and contrast are two of the most important elements of spatial heterogeneity, few studies have tested effects of scale and contrast of soil nutrient het- erogeneity on the growth of clonal plants. Methods We conducted a greenhouse experiment in which we grew individual ramets of a rhizomatous clonal plant, Bolboschoenus planiculmis (synonym Scirpus planiculumis), in heterogeneous conditions consisting of nu- trient-rich and nutrient-poor patches. The experiment had two levels of patch scale (large vs. small patch) crossed with two levels of patch contrast (high vs. low contrast), thereby consisting of four treatments. In each treatment, the total area of the nutrient-rich patches and that of the nutrient-poor patches were the same, and the total amount of soil nutrients was also the same in all the four treatments. Important findings At both clone (whole plant) level and patch level, patch scale, contrast or their interaction did not significantly affect biomass, number of ramets, total rhizome length or number of tubers of B. planiculmis. At the patch level, however, biomass, number of ramets, total rhizome length and number of tubers of B. planiculmis were significantly greater in the nutrient-rich patches than in the nutrient-poor ones, whereas spacer length (i.e., distance between adjacent ramets) was smaller. Such effects depended on neither patch scale nor patch contrast. Therefore, when growing in environments with heterogeneous soil nutrients, B. planiculmis was able to shorten its spacer length and likely also increased branching intensity of the rhizomes, such that more ramets and tubers (i.e., potential ramets) were placed in nutrient-rich patches. These responses are generally considered one aspect of the foraging behavior of clonal plants and are thought to be adaptive. However, the patch scale or contrast designed in the present experiment could not affect the placement of the ramets in the heterogeneous environments. We presume that the responses of B. planiculmis are likely different if a wider range of scale and contrast is used and thus future studies to test effects of scale and contrast of resource heterogeneity should consider a wider range of scale and/or contrast.

Interspecific coordination and intraspecific plasticity of fine root traits in North American temperate tree species.

Fine roots play an important role in nutrient and water absorption and hence overall tree performance. However, current understanding of the ecological role of belowground traits lags considerably behind those of aboveground traits. In this study, we used data on specific root length (SRL), fine root diameter (D) and branching intensity (BI) of two datasets to examine interspecific trait coordination as well as intraspecific trait variation across ontogenetic stage and soil conditions (i.e., plasticity). The first dataset included saplings of 12 North American temperate tree species grown in monocultures in a common garden experiment to examine interspecific trait coordination. The second dataset included adult and juvenile individuals of four species (present in both datasets) co-occurring in natural forests on contrasting soils (i.e., humid organic, mesic, and xeric podzolic).The three fine root traits investigated were strongly coordinated, with high SRL being related to low D and high BI. Fine root traits and aboveground life-strategies (i.e., relative growth rate) were weakly coordinated and never significant. Intraspecific responses to changes in ontogenetic stage or soil conditions were trait dependent. SRL was significantly higher in juveniles compared to adults for Abies balsamea and Acer rubrum, but did not vary with soil condition. BI did not vary significantly with either ontogeny or soil conditions, while D was generally significantly lower in juveniles and higher in humid organic soils. D also had the least total variability most of which was due to changes in the environment (plasticity). This study brings support for the emerging evidence for interspecific root trait coordination in trees. It also indicates that intraspecific responses to both ontogeny and soil conditions are trait dependent and less concerted. D appears to be a better indicator of environmental change than SRL and BI.

Leaf size versus leaf numbertrade-offs in dioecious angiosperms

Aims We explore the possible role of leaf size/number trade-offs for the interpretation of leaf size dimorphism in dioecious plant species. Methods Total above-ground biomass (both male and female) for three herbaceous dioecious species and individual shoots (from both male and female plants) for three woody dioecious species were sampled to record individual leaf dry mass, number of leaves, dry mass of residual above-ground tissue (all remaining non-leaf biomass), number of flowers/inflorescences (for herbaceous species) and number of branches. Important Findings For two out of three woody species and two out of three herbaceous species examined, male plants produced smaller leaves but with higher leafing intensity—i.e. more leaves per unit of supporting (residual) shoot tissue or plant body mass—compared with females. Male and female plants, however, did not differ in shoot or plant body mass or branching intensity. We interpret these results as possible evidence for a dimorphic leaf deployment strategy that promotes both male and female function, respectively. In male plants, capacity as a pollen donor may be favored by selection for a broadly spaced floral display, hence favoring relatively high leafing intensity because this provides more numerous axillary meristems that can be deployed for flowering, thus requiring a relatively small leaf as a trade-off. In one herbaceous species, higher leafing intensity in males was associated with greater flower production than in females. In contrast, in female plants, selection favors a relatively large leaf, we propose, because this promotes greater capacity for localized photosynthate production, thus supporting the locally high energetic cost of axillary fruit and seed development, which in turn requires a relatively low leafing intensity as a trade-off.

Analysis of statistical model properties from discrete nuclear structure data

Experimental M1, E1, and E2 photon strengths have been compiled from ex- perimental data in the Evaluated Nuclear Structure Data File (ENSDF) and the Evaluated Gamma-ray Activation File (EGAF). Over 20,000 Weisskopf reduced transition proba- bilities were recovered from the ENSDF and EGAF databases. These transition strengths have been analyzed for their dependence on transition energies, initial and final level ener- gies, spin/parity dependence, and nuclear deformation. ENSDF BE1W values were found to increase exponentially with energy, possibly consistent with the Axel-Brink hypothesis, although considerable excess strength observed for transitions between 4-8 MeV. No sim- ilar energy dependence was observed in EGAF or ARC data. BM1W average values were nearly constant at all energies above 1 MeV with substantial excess strength below 1 MeV and between 4-8 MeV. BE2W values decreased exponentially by a factor of 1000 from 0 to 16 MeV. The distribution of ENSDF transition probabilities for all multipolarities could be described by a lognormal statistical distribution. BE1W, BM1W, and BE2W strengths all increased substantially for initial transition level energies between 4-8 MeV possibly due to dominance of spin-flip and Pygmy resonance transitions at those excitations. Anal- ysis of the average resonance capture data indicated no transition probability dependence on final level spins or energies between 0-3 MeV. The comparison of favored to unfa- vored transition probabilities for odd-A or odd-Z targets indicated only partial support for the expected branching intensity ratios with many unfavored transitions having nearly the same strength as favored ones. Average resonance capture BE2W transition strengths generally increased with greater deformation. Analysis of ARC data suggest that there is a large E2 admixture in M1 transitions with the mixing ratio ≈ 1:0. The ENSDF reduced transition strengths were considerably stronger than those derived from capture gamma ray data implying that those data are strongly biased by favored, unhindered transitions.

Hydraulic function contributes to the variation in shoot morphology within the crown in Quercus crispula

Hydraulic and light environments have variation within the crown in well-grown trees. Shoot morphology and shoot hydraulics were compared between the upper and lower crown or among branching patterns in well-grown Quercus crispula Blume. Shoots in the upper crown had longer and thicker axes and lower water potential than did shoots in the lower crown. Hydraulic conductance from the soil to the shoot did not differ between the upper crown and the lower crown. Shoots in the upper crown are exposed to hydraulic stress, and shoots in the lower crown are under shade stress. Shoot morphology and shoot hydraulic traits (i.e., higher Huber value and higher hydraulic conductivity) in the upper crown affected the hydraulic conductance of shoots. Shoots in the lower crown showed larger light-receiving leaf area per leaf biomass investment, which is an adaptive morphology under shaded environments. Shoot morphology and shoot hydraulics were not correlated to branching pattern significantly, but shoots with higher branching intensity in the upper crown represented trends for higher hydraulic conductivity. These results reveal that shoot morphological and physiological characteristics in the upper crown reduce hydraulic stress, and those in the lower crown reduce shade stress. I conclude that vertical position within a crown affects both morphological and physiological acclimation for light acquisition and hydraulic conductance, and that hydraulic architecture is associated with crown architecture.

Is Branching Intensity Interspecifically Related to Biomass Allocation? A Survey of 25 Dicot Shrub Species from an Open‐Growing Dry Valley

The objective of this study was to test whether branching intensity is interspecifically correlated with the biomass allocation patterns of woody species at the level of the whole plant. For this purpose, we examined leaf size and number and branch size and number at different branch orders and computed both a commonly used measure and a newly constructed measure of branching intensity (i.e., Whitney’s parameter and γ, respectively) to determine whether biomass allocation patterns are correlated with branching intensity for 25 shrub species from a dry valley in southwest China. Whitney’s parameter (BI) was calculated as $$( N_{\mathrm{T}\,}-1) / ( N_{\mathrm{T}\,}-N_{\mathrm{t}\,}) $$ for whole plants, where NT is the total branch number at different branch orders and Nt is the number of terminal branches. Gamma was calculated as Nt divided by the maximum branch order. No significant across‐species relationship was found between BI and the quotient of leaf and stem mass. However, a positive correlation was observed between BI and the quotient of stem and root mass. In contrast, γ was negatively correlated with the quotient of leaf and stem mass but not correlated with the quotient of stem and root mass. The relationship between branching intensity and biomass allocation patterns could be understood from the allometries among the study architectural traits. In conclusion, branching intensity is interspecifically correlated with biomass allocation patterns. However, the correlation is parameter specific, because different measures of branching intensity produce different kinds of correlations.

Enhancement of Artemisinin Content through Four Cycles of Recurrent Selection with Relation to Heritability, Correlation and Molecular Marker inArtemisia annuaL.

Due to the high demand and low yield of the anti-malarial drug artemisinin in natural populations of Artemisia annua (Quinghao), an attempt has been made to enhance the artemisinin content through 4 cycles of recurrent selection (C(0)-C(3)) using selected genotypic and phenotypic traits. Based on their phenotypic and genotypic characteristics, the top 5% plants of each cycle were selected, and their seedlings were planted in poly-cross block to produce seeds for the subsequent generation. A significant increase in the artemisinin content (0.15% in C (0) to 1.16% in C (3), i.e., about 40% genetic gain over the generation) was observed. This enhancement was directly correlated with the plant height and branching intensity in all four cycles. Similarly, the PCV (phenotypic coefficient of variation) and GCV (genotypic coefficient of variation) have been observed to have a higher value for artemisinin content. The DNA marker (MAP 12) with relation to artemisinin was also identified for high yielding genotypes in all four cycles of selection. Over the four cycles of recurrent selection, the plant developed an oval appearance (Variety: CIM-Arogya) and a high artemisinin content (1.16%).

Fractal and shape analyses of manganese dendrites on vein quartz

Manganese dendrites are common along joint planes in a quartz vein in Selayang, northern Kuala Lumpur. Individual dendrites mainly range from about 5 cm to 50 cm in length. They have variable shapes that range from simple shape with few branches to complex intricately branched patterns. Dendrites having different patterns may be found together along the same joint plane and some simple dendrites developed into more intricate forms. Digital photographs of dendrites were taken in the field and then converted to single bit images for fractal analysis. The images were also vectorised to measure the perimeter and area of the dendrites as well as the enclosing convex hull. These basic measurements were used to obtain the fractal dimension, lacunarity, PARIS factor, divergent ratio, fractal divergent ratio and fill factor for nine samples, which cover dendrites of various forms and complexities. The fractal dimension of the dendrites measured using box counting algorithm ranges from 1.57 to 1.88. Generally, dendrites with broad and short branches have larger fractal dimension and those that have thin and long branches have smaller fractal dimension. Lacunarity and fill factor also show the same trend, while PARIS factor, divergent ratio and fractal divergent ratio values are higher in complex and intricately branched dendrites. There are dendrites with similar fractal dimension but have dissimilar patterns. At the same fractal dimension, the lacunarity is smaller for more complex and intricately branched dendrites, while the fractal divergent ratio is larger for dendrites with thinner branches. Although the values of both PARIS factor and divergent ratio increase with the increase in the intensity of branching, these parameters cannot be clearly related to the variation in the pattern of dendrites.

Species delimitation in the European species of Clavulina ( Cantharellales, Basidiomycota) inferred from phylogenetic analyses of ITS region and morphological data

The identification of the conventionally accepted species of Clavulina ( Cantharellales, Basidiomycota) in Europe ( Clavulina amethystina, Clavulina cinerea, Clavulina cristata, and Clavulina rugosa) is often difficult and many specimens are not straightforwardly assignable to any of those four species, which is why some authors have questioned their identity. In order to assess the status of those species, a morphological examination was combined with the molecular analysis of the ITS region. The same six major clades were obtained in the Bayesian and parsimony phylogenetic analyses, and all six clades were well-supported at least by one of the analyses. Morphological characters, such as the overall branching pattern, the presence and intensity of grey colour, the cristation of the apices, and basidiospore size and shape were to various extents correlated with the phylogenetic signal obtained from the ITS region. The congruence between the molecular analyses and morphology, rather than geographical origin, suggests the existence of several species that can be delimited using a combined phylogenetic and morphological species recognition. The analyses revealed that C. cristata and C. rugosa are well-delimited species. In contrast, more than one taxa could be subsumed under the names C. amethystina and C. cinerea, the taxonomical complexity of which is discussed. The ITS region is proved to be adequate to separate phylogenetic species of Clavulina.

Patterns in root trait variation among 25 co‐existing North American forest species

Ephemeral roots have essential roles in plant and ecosystem functioning. In forests, roots account for a major component of carbon cycling, yet few studies have examined ranges of root trait variation and how different species vary in root form and function in these communities. Root branching intensity, specific root length (SRL; root length per unit dry mass), root diameter, tissue density, phenolic concentration and nitrogen concentration were determined for the finest two root orders of 25 co-existing North American woody species sampled from mature plants in a single forest community. Trait correlations and multivariate patterns were examined to evaluate the most important trait differences among species. Branching intensity, SRL, and phenolic concentration varied most widely among species (coefficient of variation (CV) = 0.42, 0.57 and 0.58, respectively). Species predominately forming ectomycorrhiza (EM) had a higher branching intensity than those forming arbuscular mycorrhiza (AM) with mycorrhizal types correctly predicted in c. 70% of individual observations by branching intensity alone. There was notably no correlation between SRL and nitrogen. Variation in SRL among species mapped partially along phylogenetic lines (consistency index (CI) = 0.44), with remaining variation attributable to differences in species' ecological specialization. Variation found in root traits suggests different nutrient acquisition strategies within this community, which could have potential species-level effects on carbon and mineral nutrient cycling.