Leaf epidermal features are important taxonomic features in Quercus. We studied leaf epidermal features of 91 species and one forma of Quercus subgenus Cyclobalanopsis using light and scanning electron microscopy. Trichome terminology in oaks was assessed and clarified, aiming to score the epidermal features accurately for genus-wide comparison. Nine trichome types, anomocytic and cyclocytic stomatal apparatus, smooth layer and platelet epicuticular wax flakes, and two trichome base types were found in subgenus Cyclobalanopsis. The epidermal features revealed three main groups in subgenus Cyclobalanopsis. The epidermal features of Quercus s.l. were uniform, supporting recognition of Cyclobalanopsis as a subgenus of Quercus rather than as a separate genus. Most leaf epidermal features show a mosaic pattern, although their numerous variations offered valuable resources for species identification. The leaf epidermal features that can be used for identification of Quercus leaves are also discussed and summarized.

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Aeschynanthus longicaulis plants are understory plants in the forest, adapting to low light conditions in their native habitats. To observe the effects of the high irradiance on growth and physiology, plants were grown under two different light levels, PPFD 650 μmol·m–2 ·s–1 and 150 μmol·m–2 ·s–1 for 6 months. Plants under high irradiance had significantly thicker leaves with smaller leaf area, length, width, and perimeter compared to the plants grown under low irradiance. Under high irradiance, the leaf color turned yellowish and the total chlorophyll decreased from 5.081 mg·dm−2 to 3.367 mg·dm−2. The anthocyanin content of high irradiance leaves was double that of those under low irradiance. The plants under high irradiance had significantly lower Amax (5.69 μmol·m–2 ·s–1) and LSP (367 μmol·m–2 ·s–1) and higher LCP (21.9 μmol·m–2 ·s–1). The chlorophyll fluorescence parameter F v/F m was significantly lower and NPQ was significantly higher in high irradiance plants. RLCs showed significantly lower ETRmax⁡ and E k in plants under high irradiance. It can be concluded that the maximum PPFD of 650 μmol·m–2 ·s–1 led to significant light stress and photoinhibition of A. longicaulis.

Quercus lineata is native to Malaysia and Indonesia. During our studies on herbarium collections and field collections, two new distribution records of Q. lineata were found in Hainan island, South China and Central Vietnam. All the key diagnostic features of the specimens from China and Vietnam were consistent with the specimens collected from Malaysia. The leaf anatomical features of the populations of different regions were compared. We also addressed the conservation status and biogeographic implications of the distribution of Q. lineata.