A medium to large
herbaceous plant that can reach a height of 80 to 160 cm, the plant is glabrous throughout. The leaves are subcoriaceous and gradually elongate from the base of the plant to the upper internodes. The leaves near the base are peltate-ovate, approximately 35 cm in diameter, with long petioles and peltate-shaped attachments. The lamina is palmately deeply-lobed, resembling an upright umbrella on the ground. The lobes are generally 5 to 9 in number and are bifid (once or twice) with an acute apex and irregularly incised serrations along the leaf margin. The cauline leaves on the upper part of the plant are smaller in size, with shorter petioles, narrower lamina, and less obvious leaf lobes. The inflorescences are light pink and corymbose on the inflorescence axis. A single flower head is composed of about 14 to 16 tubular flowers, surrounded by two whorls of involucral bracts. The corolla of a single flower is five-lobed and white, with a pedicel 5 to 16 mm in length. This species, and another endemic plant of Taiwan,
Syneilesis subglabrata are in the same genus. They can be effectively distinguished by their geographical distribution, inflorescence, and leaf lobe morphology.
Syneilesis hayatae is only distributed in the lowland grasslands of Miaoli, with robust plants and corymbose head flowers and shallower serrations along the leaf margin (approaching serrated margins).
Syneilesis subglabrata is endemic to the mountainous regions of central Taiwan, found under the forest canopy at an altitude of 1200 to 2800 meters. The plant is slender, the flower heads are arranged conically, and the serrations along the leaf margin are deeper (approaching lobes). == Distribution and habitat ==