Two new wood-inhabiting fungi, Sidera salmonea sp. Nov. and S. tibetica sp. Nov. in the order Hymenochaetales from southwest China, are described and illustrated based on molecular and morphological evidence. They were found on gymnosperm wood that is rotten and charred. The characteristics of S. salmonea include annual, resupinate basidioma, salmon pores with distinctly white margins, angular pores (7–9 per mm), a dimitic hyphal system, and lunate basidiospores that are 3–3.5 × 0.9–1.1 μm. The characteristics of S. tibetica include annual, resupinate basidioma with a white to cream fresh pore surface that becomes cream to honey-yellow and shiny when dry, round pores (7–8 per mm), a dimitic hyphal system, and lunate basidiospores that measure 2.9–3.1 × 1–1.1 μm. A phylogenetic analysis based on the combined 2-locus dataset (5.8S + nuclear large subunit RNA (nLSU)) shows that the two species are members of the genus Sidera, and they are morphologically compared with related species, respectively. This paper provides a key to the identification of 16 accepted species of Sidera that are found throughout the world.

Fine roots play a prominent role in forest carbon flux, nutrient and water acquisition; however, information on fine roots remains scarce due to the limitation of measuring methods. In this study, a nested regression method was used to estimate the biomass and surface area of fine roots of individual Larix gmelinii trees that dominate northernmost China. Aboveground traits including leaf biomass, leaf area, stem volume and aboveground biomass were also investigated. In particular, the relationships between leaves and fine roots, in terms of biomass and area, were examined. The results revealed that allometric models of fine roots, total roots, and leaves consistently fit well with Adj. R² = 0.92–0.97. The root-shoot ratio at the individual tree level was approximately 0.28. There were robust positive linear correlations between absorption (fine root biomass, fine root surface area) and production (leaf biomass, leaf area) (Adj. R² = 0.95, p < 0.001). In conclusion, the close coupling between fine roots and leaves presented in this study provides support for the theory of functional equilibrium.

Accurate estimates of tree component and aboveground biomass strongly depend on robust and precise allometric equations. However, site-specific and suitable biomass equations are currently scarce for natural Larix gmelinii forests in the western Daxing’anling Mountains, northeastern China. This study aimed to evaluate the biomass allocation patterns within tree components and develop additive allometric biomass equations for species of L. gmelinii. A total of 58 trees were destructively sampled and measured for wood (inside bark), bark, branch and leaf biomass. For each component, we assessed the share of biomass allocated to different components by computing its ratio; we also tested two allometric equations based on diameter at breast height (dbh) alone, and dbh fitted with height (h) as independent variables. Seemingly unrelated regression methodology was used to fit an additive system of biomass allometric equations. We performed an independent dataset to evaluate the predictive ability of the best model system. The results revealed that wood biomass accounted for approximately 60% of the aboveground biomass. Wood and branch biomass ratios increased with increasing dbh, while a reverse trend was observed for bark and leaf biomass ratios. All models showed good fitting results with Adj.R² = 0.958–0.995. Tree dbh provided the lowest estimation errors in the regressions associated with branches and leaves, while dbh² × h generated the most precise models for stems (wood and bark). We conclude that these allometric equations will accurately predict biomass for Larix trees in the western Daxing’anling Mountains.

Two new species of Globisporangium, G. pengfuense and G. tenuihyphum, that were isolated from soybean in China are described and illustrated based on their morphological characters and molecular evidence. The characteristics of G. pengfuense include globose to sub-globose sporangia that are: catenulate, terminal, occasionally with apical papillae or intercalary, smooth oogonia, mostly monoclinous, occasionally diclinous antheridia, fist-shaped to crook-necked, with straight or curved antheridial cells, and plerotic or nearly plerotic with thin-walled oospores (0.5–1.0 µm). Globisporangium tenuihyphum differs from other species in this genus by its relatively narrow hyphae that are: mostly sub-globose to globose, occasionally ovoid-obpyriform sporangia, smooth oogonia, monoclinous antheridia, subclavate, falcate or semicircular to subcircular antheridial cells, and with aplerotic oospores. Phylogenetically, data from the combined internal transcribed spacer (ITS) and cytochrome c oxidase subunit I (Cox1) sequences support the designation of G. pengfuense and G. tenuihyphum as two distinct species of Globisporangium (Pythium sensu lato clades G and J). In addition, the two new species were compared to closely related Globisporangium species, to delineate their phylogenetic positions and morphological features.