Two new species of Thismia subsect. Odoardoa (Thismiaceae) from Borneo

Background – Two new species of the sect. Thismia subsect. Odoardoa, Thismia cornuta Hroneš, Sochor & Dančák and Thismia pallida Hroneš, Dančák & Rejžek, from Malaysian Borneo are described and illustrated. The former species is distributed in the Bario area of the Kelabit Highlands of Sarawak, and the latter occurs in the SAFE (Stability of Altered Forest Ecosystem) Project area, northwest of Tawau in Sabah. Methods – This study is based on field observations in several forest localities in Sarawak and Sabah and herbarium material deposited in SAN, SAR and OL. Both conventional herbarium techniques and comparison with protologues of described species were applied. Results – Thismia cornuta is morphologically closely related to T. inconspicua Sochor & Dančák from Brunei Darussalam and T. chrysops Ridl. from the Malay Peninsula but it differs from both species by the presence of only two appendages at apical margin of the connective, by horn-like projection on each side of the lateral appendage and by white colour of perianth tube. It was found at three localities and is preliminarily treated as endangered (EN). Thismia pallida is morphologically close to T. filiformis Chantanaorr. from Thailand but differs by the presence of five appendages at apical margin of connective, by box-shaped lateral appendage exceeding apex of connective and by shorter filiform appendage of perianth lobe. It was found at a single locality within twice logged secondary forest and it is preliminarily treated as critically endangered (CR). This is only the second record of Thismia species inhabiting secondary forests in tropical Asia.