Anatomical adaptations of Launaea sarmentosa (Willd.) Kuntze (Asteraceae) from the Andaman coast, Thailand

Launaea sarmentosa (Willd.) Kuntze, a threatened coastal species endemic to the Andaman coastline of Thailand, is undergoing significant population decline due to habitat degradation. Despite its ecological and economic importance, limited knowledge exists regarding its anatomical adaptations to coastal environments, knowledge that is essential for effective conservation and restoration strategies. This study aimed to comprehensively investigate the vegetative anatomy of L. sarmentosa and to identify taxonomically significant features that reflect its adaptation to environmental stressors. Samples of leaves, stems, stolons and roots were collected from Mai Khao Beach, Phuket and examined using paraffin embedding and light microscopy techniques. The results revealed several adaptive features, including amphistomatic leaves, thick cuticlar layers, homobaric leaf structure and the formation of periderm in stems and roots. Stomatal density was significantly higher on the adaxial surface compared to the adaxial surface, indicating differential regulation of gas exchange. The presence of a thick cuticle and epidermis further highlights its adaptations to the harsh coastal environment, characterized by high light intensity and drought conditions. Stolons exhibited chlorenchyma and stomata, suggesting their role in photosynthesis and water regulation. These anatomical traits reflect the ability of L. sarmentosa to thrive in dune habitats and provide essential information for future conservation and habitat restoration initiatives. Understanding these adaptations is crucial for the effective preservation and rehabilitation of this species.