Alstonia iwahigensis  Alstonia iwahigensis grows as a medium to large-sized tree up to tall, with a trunk diameter of up to . The bark is greyish, yellowish or dark brown. Its fragrant flowers feature a yellow or pinkish corolla. The plant is found in forests and on hillsides from sea-level to altitude. "A. iwahigensis" is native to Borneo and the Philippines.