Among the widely cultivated poplars, some of the most significant are those developed by Ernst J. Schreiner and Arlow B. Stout. These poplars were developed through controlled hybridization in the United States in the early 20th century, and the selected clones were efficiently distributed worldwide over the following decades. Despite their apparent prevalence in cultivation, their identification remains a significant challenge. Among the most frequently grown Schreiner and Stout clones are those derived from the crosses Populus suaveolens × P. trichocarpa and P. suaveolens × P. ×berolinensis. However, formal names were never proposed for these hybrids; consequently, they must be assigned to individual clones, further complicating their nomenclature. In this paper, based on historical data, morphological studies, and anatomical analyses of leaf petioles, it is demonstrated that these hybrids possess distinct characteristics that facilitate easy identification. Two new nothospecies, Populus ×schreineri and Populus ×stoutii are proposed and described. Both taxa exhibit clear hybrid traits; however, P. ×schreineri is morphologically closer to P. suaveolens (sect. Tacamahaca), while P. ×stoutii shows a distinct influence from the black poplar section (sect. Aigeiros). The main diagnostic features enabling their identification are highlighted, with particular emphasis on the petiole anatomy.
The widespread decline of Norway spruce has led to larger gaps in the canopy of Central European mountain forests, potentially affecting the regeneration of shade tolerant silver fir (Abies alba Mill.). We examined whether greater light availability in canopy gaps influences the morphology of fir needles and fine roots, their carbohydrate concentrations, and their fungal associations, as trees may respond to environmental changes in both their canopy and in their belowground interactions. We compared small patches of fir trees under a closed canopy and low light conditions with regenerating patches growing in gaps with greater light transmission (i.e. canopy gap). We quantified understory photosynthetically active photon flux density (PPFD%), soil water storage, shoot apical dominance, needle specific leaf area (SLA), fine root traits (AD- average diameter, SRL- specific root length, SRA- specific root area), root and leaf tissue nitrogen (N), non-structural carbohydrates (TNC), and characterized root-associated fungi via ITS2 sequencing. Canopy gaps had 1.5 times higher PPFD and reduced soil water storage. Silver fir individuals in canopy gaps also displayed greater apical dominance, thinner roots, and longer SRL and greater SRA compared with individuals under a closed canopy. Contrary to our expectations, the concentrations of soluble sugars and total non-structural carbohydrates were higher under the closed canopy. Meanwhile, gap saplings exhibited higher tissue nitrogen levels in both roots and needles. Light availability also influenced belowground symbiosis as canopy gaps saplings hosted a more diverse ectomycorrhizal fungal community (higher α-diversity), whereas the long-distance morphotype of Boletus occurred under a closed canopy and covaried positively with carbohydrate pools and negatively with SRL. These linked changes illustrate a shift from carbon conservative, symbiont supported growth in shaded patches to more acquisitive root strategies in canopy gaps.
Information on edible mushrooms among the indigenous societies of South America’s lowlands is scarce. Recent studies suggest that indigenous Amazonian groups exhibit a spectrum ranging from intense mycophobia to mild mycophilia. The Asháninka people, who belong to the Arawak language family, are the largest group in the Peruvian Amazonia. They have inhabited the tributaries of the Ucayali River for centuries, mainly dedicating themselves to horticulture and fishing, with a lesser emphasis on foraging. This is the first study of edible mushroom gathering and consumption among the Asháninka people and the second among Arawakan groups in the Peruvian Amazonia. Field research was conducted in the Asháninka communities of Upper Peruvian Amazonia in 2022 and 2024. Taxonomic identification was based on DNA barcoding. The Asháninka collect and consume over ten species of edible lignicolous fungi. This is the first recorded instance of Cookeina spp. consumption in the Peruvian Amazonia. The mushrooms are primarily consumed in soups, baked in leaf wraps over embers, or fried with eggs during the wet season (December–May). Our findings contradict previous assumptions of Amazonian indigenous mycophobia. We hypothesise that the absence of ectomycorrhizal mushrooms in this society and other Amazonian groups is due to the scarcity of ectomycorrhysis in the Neotropics rather than mycophobia among the local human populations.
Quercus vulcanica Boiss. & Heldr. ex Kotschy and Q. frainetto Ten. are closely related oak species with little genetic differentiation and slight morphological differences in Türkiye possibly as result of hybridization and phenotypic plasticity. While leaf morphology offers strong phenotypic cues for quantitative studies, traditional morphometrics frequently fails to capture these fine-scale differences. The objective of this study is to use geometric morphometrics to measure symmetric and asymmetric leaf shape variation using allometric effects and determine how population-level morphological differentiation, putative hybridization and altitude affect the interspecific differentiation between these two species. A total of 222 leaves from four Q. vulcanica and two Q. frainetto populations in Türkiye were digitized at 13 homologous landmarks to capture bilateral leaf geometry, enabling the analysis of symmetric and asymmetric shape variation. Generalized Procrustes Analysis, PCA, discriminant analysis and allometric and correlation assessments were performed in MorphoJ and SPSS to evaluate interspecific differences, population-level variation and associations with diameter at breast height and altitude. These analyses revealed that interspecific differentiation between Q. vulcanica and Q. frainetto is primarily associated with symmetric leaf shape components, particularly lamina width, lobe expansion, and petiole morphology, whereas asymmetric variation showed extensive overlap and lacked taxonomic relevance. 2B-PLS analyses indicated a weak to moderate association between leaf size and symmetric shape variation, especially in Q. vulcanica, while asymmetric shape variation was largely independent of size. Population-level comparisons showed clear morphological differentiation with low putative hybridization (2.9–12.2%) based on morphometric intermediacy criteria, and correlations with tree diameter highlighted size-dependent shape changes in Q. vulcanica, whereas altitude had little influence on leaf morphology in either species. It will be crucial to conduct future studies that integrate geometric morphometrics with genomic, eco-physiological and experimental methods over wider environmental gradients. Such integrative research will clarify the relative contributions of plasticity, adaptability and developmental constraint to the evolution of oak leaf shapes.
Increasing attention has recently been given to the connections between the two systems of secondary vascular tissues. Due to the dependencies described thus far between developing vessel elements and xylem rays, it was decided to analyze the influence of ray proximity on the tangential dimension of developing vessel element, as well as the effect of vessel element development on the width of neighboring ray. We hypothesized that rays act as obstacles to the tangential enlargement of vessel elements, thereby influencing their final tangential dimension, and that the enlargement of vessel elements is associated with localized changes in the width of the rays they encounter during growth. Two anatomical techniques were used to obtain tangential and transverse sections of the secondary xylem of Norway maple and pedunculate oak. In maple wood, the tangential dimension of vessels in contact with rays was measured, while in oak wood, the width of rays in contact with fully developed vessels was recorded. The anatomical and statistical analyses revealed a reduction in the tangential dimension of vessel that contacts ray, and showed that the tangential growth of vessel element is associated with a local decrease in the width of the ray it encounters. These findings indicate that rays generally act as obstacles to vessel element growth, independent of whether growth is intrusive or symplastic. Considering their biomechanical properties, we propose that rays may play a buffering role within the secondary xylem differentiation zone – limiting not only the tangential intrusive growth of vessel elements but also affecting their overall tangential enlargement. In addition, three theoretical explanations were introduced to account for the observed reduction in the average width of rays.
