Byttneria Loefl., a former genus of Sterculiaceae s.s., is now placed under subfamily Byttnerioideae in the family Malvaceae (Stevens, 2001 onwards). This pantropical genus with approximately 135 species, is separated from its closely related genus Ayenia L. based on the morphologies of androecium and petals. However, recent phylogenetic analysis showed that Byttneria is paraphyletic (a group of organisms which contains a common ancestor and some, but not all, of the descendants) with Ayenia nested within it (Whitlock & Hale, 2011). This had led to the combination of these two genera into one. Thus, the members of Byttneria have been transferred into Ayenia though the changes have not been widely accepted or validly published, including most species known in Peninsular Malaysia viz. Byttneria curtisii Oliv., B. elegans Ridl., B. jackiana Wall., B. maingayi Mast. and B. mastersii Cristóbal (POWO, 2021; IPNI, 2021).
Byttneria maingayi is distributed in Peninsular Malaysia, Borneo and Singapore. In Peninsular Malaysia, it has been recorded from Pahang, Negeri Sembilan and Johor. This unarmed liana can be found in both primary and secondary lowland forests, hanging on the trees near forest pathways or roadsides.
This species can be recognized by the leaves which are usually elliptic-oblong, rarely ovate, 9–22 cm long, 3–9 cm wide and glabrous on both surfaces; the petiole is glabrous and much longer up to 10.5 cm long with swollen at both ends; and the bristle on capsule is shorter from 2 to 3 mm long (vs. 5–9 mm long in other Peninsular Malaysian species). The inflorescences are axillary or in lateral along the stem, and the 5–7 flowers arranged in cyme on 2–6 cm long peduncle. The calyx is white, 5-merous, lobes ovate-lanceolate, 4–8 mm long. As shown in the picture, the corolla is yellow, with long, slender tips, and clawed which fold backwards to connect to the base of the calyx lobes, sheltering the stamens. The stamens are five and pale yellow while the ovary is red. The base of calyx and rim of inner corolla lobes are also red.
Byttneria, though this genus has medicinal value potential, is not documented yet for all species found in Peninsular Malaysia. However, medicinal value for certain species in the genus has been recorded elsewhere, for example, Byttneria pilosa Roxb. is used for bone fractures, boils, scabies, rheumatalgia, snake bites, syphilis, elephantiasis, poisoning and eye infection in Bangladesh (Sikder et al., 2022), while different parts of Byttneria herbacea Roxb. are used to treat different disease conditions such as wounds, fractures, cholera, dysentery, leucorrhoea and swelling in India (Sharma & Acharya, 2021).
Byttneria maingayi has been assessed as Critically Endangered (CR) in Singapore (Neo et al., 2014), but has not been evaluated yet for its conservation status in Peninsular Malaysia.