<![CDATA[The genus Dinochloa Buse (Poaceae) comprises a diverse group of climbing bamboos distributed throughout Malesia, yet its diversity in the Philippines remains insufficiently documented. Field surveys conducted in the lowland ultramafic forests of the Mount Hamiguitan Range Wildlife Sanctuary, Mindanao, Philippines, revealed four previously undescribed species of Dinochloa. This study formally describes Dinochloa rubra, Dinochloa torretae, Dinochloa adonii, and Dinochloa hamiguitanensis based on detailed vegetative morphological analyses of voucher specimens collected from elevations of 340–570 m above sea level. Species delimitation was established through comparative assessment of diagnostic characters, including culm coloration, culm diameter, sheath persistence and indumentum, auricle and ligule morphology, branching patterns, and foliage-leaf characteristics. D. rubra is distinguished by bright red young culms turning dark violet, caducous light-purple culm sheaths with narrowly linear caducous blades, and the absence of auricles and oral setae, and possesses glabrous nodes and foliage leaves. D. torretae is characterized by almost solid, very slender culms (0.2–0.3 cm diameter), small auricles bearing long hairs, and culm-leaf and foliage-leaf ligules crowned with erect hairs. D. adonii differs in having larger culms (1.3–1.8 cm diameter), persistent scabrid sheaths with stiff hairs, and ovate-lanceolate sheath blades with small auricles bearing short hairs. D. hamiguitanensis is distinguished by smaller culms (0.8–1.0 cm diameter), pale orange to golden-brown scabrid culm sheaths lacking auricles and oral setae, and the absence of a foliage-leaf ligule combined with glabrous concolorous lanceolate leaves. These discoveries emphasize the ecological and conservation significance of ultramafic ecosystems as centers of bamboo endemism and diversity. Recognition of these four new species increases the number of documented Philippine Dinochloa species from eight to twelve and highlights Mount Hamiguitan as an important center of bamboo diversity and conservation. Keywords: Bambusoideae, Dinochloa, Mount Hamiguitan, Poaceae, taxonomy]]>
