Trivalvaria (Miquel, 1860)

Johnson, David M., Chaowasku, Tanawat, Murray, Nancy A. & Chalermglin, Piya, 2021, Three new species of Trivalvaria (Annonaceae) from Thailand, with a key to the Thai species, Phytotaxa 489 (1), pp. 79-86 : 84-85

Trivalvaria in Thailand

With the addition of these new species, Thailand now appears to be the centre of Trivalvaria species diversity. The Thai species, along with T. pumila from Peninsular Malaysia, are distinguished in the following key.

Trivalvaria pumila occurs throughout Peninsular Malaysia and may be expected in Thailand. Ridley (1915) reported it from Thailand as 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. pumila a distinct species, as distinguished in the key, but van Heusden (1997) treated it a synonym of T. dubia , and Turner (2009) considered T. pumila a synonym of T. costata . In the material we studied, T. pumila was most similar to T. stenopetala .

Trivalvaria costata and T. dubia are treated as distinct species here. Trivalvaria costata s.str. ( Fig. 3D,E ) is widespread in southeastern and Peninsular Thailand. The type of Trivalvaria dubia is from the Andaman Islands. Specimens resembling the type of T. dubia in their rounded petals and hairy anther connectives have been collected in Phuket Province in 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 “ Trivalvaria sp. 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. costata has 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 ).

Figures

FIGURE 3. Trivalvaria species with 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.