Mitrephora sukhothaiensis sp. nov. A vegetative branch B, C flowers D, E sepals (ab- and adaxial) F, G outer petals (ab- and adaxial) H, I inner petals (ab- and adaxial, showing marginal protrusions) J, K stamens (ab- and adaxial) L carpel M fruit, composed of separate monocarps. Drawn by A. Somphrom, A–L from P. Chalermglin 641210 (PSU), M from P. Chalermglin 650501 (PSU).