Two new species and two new records of Artabotrys (Annonaceae) from Thailand

Abstract. Two new species of Artabotrys are described from Thailand. Artabotrys tanaosriensis J.Chen, Chalermglin & R.M.K.Saunders, sp. nov., is similar to A. oblanceolatus Craib but differs in its symmetrical, cuneate or decurrent leaf base, externally distinct outer petal blades and claws, deltoid and undulate outer petal blades, rhomboid and undulate inner petal blades and shorter, subsessile and slightly beaked monocarps. Artabotrys spathulatus J.Chen, Chalermglin & R.M.K.Saunders, sp. nov., is most similar to A. tanaosriensis but differs in having flat outer petal blades, broadly rhomboid outer petal claws, broadly spathulate and strongly concave inner petal blades and strongly beaked monocarps. Two new records for the Flora of Thailand are furthermore reported here: A. punctulatus C.Y.Wu ex S.H.Yuan and A. byrsophyllus I.M.Turner & Utteridge, which were previously confused with A. aeneus Ast and A. grandifolius King, respectively. A key to Artabotrys species indigenous to Thailand is provided here.