Identifikasi Morfologi dan Anatomi Tumbuhan Ulin (Eusideroxylon zwageri Teijsm. & Binn.) Melalui Scanning Electron Microscope Sebagai Sumber Belajar Biologi

This study aims to describe the morphological characteristics and anatomical structures of Eusideroxylon zwageri, and to develop a visual-based e-atlas as a contextual biology learning resource. Eusideroxylon zwageri, an endemic species with high ecological and economic value, is currently under threat due to limited distribution and overexploitation. The research employed a descriptive-explorative method and the ADDIE development model. Samples were collected from the root, stem, and leaf parts of ulin plants found in Balikpapan City. Observations were conducted macroscopically and microscopically using a Scanning Electron Microscope (SEM). Morphological analysis showed that the leaves are elliptical to ovate with entire margins, pinnate venation, and the presence of cuticle and non-glandular trichomes on the abaxial surface. Stems grow monopodially with tomentose textures and patent branching patterns. The root system is strong and taproot-dominated with lateral extensions. Anatomical structures observed through SEM revealed the presence of anomocytic stomata, thick-walled xylem vessels, well-developed sclerenchyma tissues, parenchyma with large vacuoles, and a clearly visible Casparian strip in the endodermis. All collected data were compiled into a structured e-atlas, combining visual micrographs and scientific narratives. The validation process involved subject matter experts, instructional material specialists, and biology teachers. The validity was assessed using Akbar's (2013) instrument, resulting in an overall score of 88.5%. The content expert rated the product at 96.7%, the instructional material expert at 87%, and the practical user at 82%. These findings indicate that the e-atlas is highly valid and suitable for academic use. The final product is accessible in digital format and is designed to enhance conceptual understanding through interactive and visual learning. This research contributes to the development of contextual and science-based educational resources that support the conservation of Indonesia’s endemic plant species. The e-atlas serves as a strategic tool to improve scientific literacy, observation skills, and student awareness regarding biodiversity and sustainability.