Trivalvaria pumila Ellipeia pumila King (1892: 27) T. pumila T. dubia T. pumila T. costata T. pumila T. stenopetala Trivalvaria species Trivalvaria macrophylla Trivalvaria costata Trivalvaria dubia Trivalvaria costata T. dubia Trivalvaria costata Trivalvaria dubia T. dubia T. dubia Trivalvaria sp. 1 T. costata Three new species of Trivalvaria (Annonaceae) from Thailand, with a key to the Thai species Johnson, David M. Chaowasku, Tanawat Murray, Nancy A. Chalermglin, Piya Phytotaxa 2021 2021-03-03 489 1 79 86 82NB 235845 Miquel 1865 Miquel 1860 [136,264,445,472] Magnoliopsida Annonaceae Trivalvaria Plantae Magnoliales 5 84 Tracheophyta genus    Trivalvaria pumilaoccurs throughout Peninsular Malaysiaand may be expected in Thailand. Ridley (1915)reported it from Thailandas  Ellipeia pumila King (1892: 27)from the Koh Samui and Koh Pennan [= Pha-ngan] region on the basis of a collection by H.C. Robinson. We cannot locate his specimen. We consider  T. pumilaa distinct species, as distinguished in the key, but van Heusden (1997)treated it a synonym of  T. dubia, and Turner (2009)considered  T. pumilaa synonym of  T. costata. In the material we studied,  T. pumilawas most similar to  T. stenopetala.   FIGURE 3.  Trivalvariaspecieswith which the new species have previously been confused. A–C.  Trivalvaria macrophylla, Songkhla Province, Thailand. A. Flower, viewed from above. B. Flower, side view. C. Fruit, showing the large number of short-stiped monocarps. D–E.  Trivalvaria costata, Nakhon Si Thammarat Province, Thailand. D. Flower, viewed from above. E. Flower, side view. F–G.  Trivalvaria dubia,  s. l., Phuket Province, Thailand. F. Flower, viewed from above. G. Flower, side view.A–C by Charan Leeratiwong from Leeratiwong 20-1521, D–E by Charan Leeratiwong from Leeratiwong 16-487, F–G by Simon Gardner from Gardner & Sidisunthorn ST 2595.   Trivalvaria costataand  T. dubiaare treated as distinct species here.  Trivalvaria costata s.str.( Fig. 3D,E) is widespread in southeastern and Peninsular Thailand. The typeof  Trivalvaria dubiais from the Andaman Islands. Specimens resembling the typeof  T. dubiain their rounded petals and hairy anther connectives have been collected in Phuket Provincein Peninsular Thailand( Fig. 3F,G); these have slightly different indument and leaf shape from  T. dubia s.str.; additional material is required to determine if they represent a distinct taxon. One of these specimens was used in the molecular phylogenetic analysis by Chaowasku et al.(2020, as “  Trivalvariasp. 1). Both the Andaman and Thai specimens are clearly distinct from  T. costata s.str.  The dome formed by the connivent inner petals in  T. costatahas led to confusion of this species with  T. macrophylla; the latter has larger flowers with dense silky pubescence on the inner petals and a greater number of carpels and monocarps ( Fig. 3A–C).