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Thismia cornuta Hroneš, Sochor & Dančák; Thismia pallida Hroneš, Dančák & Rejžek, in Hroneš, Rejžek, Sochor, et al., 2018. |
Abstract
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.
Keywords: Malesia; Mycoheterotrophy; Sabah; Sarawak; Tropical rain forest
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| Thismia cornuta Hroneš, Sochor & Dančák: A & B, habit of flowering plant; C, habit of flowering and fruiting plant; D, perianth tube with removed part showing stamens with anthers and lateral appendages; E, apical part of connective with appendages; F, horn-like projection on lateral appendage; G & H, style with stigma; I, type locality. Photographs: Michal Sochor (A & C–H), Michal Hroneš (B & I). A from Sochor et al.BOR10/17; B from Sochor et al. BOR24/17; C–H from Sochor et al. BOR2/17 (type). |
Thismia cornuta Hroneš, Sochor & Dančák, sp. nov.
It differs from its congeners by the combination of following morphological characters: stem very short or absent, flower slightly zygomorphic, perianth tube white and verrucose out-side, annulus pinkish, only two appendages at apical margin of the connective and small horn-like projection arising from each side of the lateral appendage.
Distribution – So far known only from the Bario area, Kelabit Highlands, Sarawak, north-western Borneo (possibly endemic).
Etymology – From the Latin cornutus (horned). The name points to the horn-like projections on lateral appendage resembling horns on a Viking helmet, a morphological trait so far not known in the genus.
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| Thismia pallida Hroneš, Dančák & Rejžek: A, habit of flowering plant; B, habit of fruiting plant; C, top view of flower showing annulus and perianth appendages; D, two-flowered plant with root system; E, outer view of stamens; F, inner view of stamens. Photographs: Michal Hroneš (A–F). A–F from Nilus & Svátek SAN 158204 (Type). |
Thismia pallida Hroneš, Dančák & Rejžek, sp. nov.
Similar to Thismia filiformis Chantanaorr. but differs in the presence of 5 (vs. 3) appendages at apical margin of the con-nective, by box-shaped lateral appendage exceeding apex of the connective, by longer perianth tube and shorter append-ages of the perianth lobes.
Distribution – So far known only from small population of seven individuals in twice selectively logged forest near SAFE Project base camp (LFE blocs), south of Danum Valley Conservation Area and northwest of Tawau, Sabah, at elevation c. 485 m a.s.l.
Etymology – From the Latin pallidus. The name refers to the pale colour of the whole plant.
Michal Hroneš, Martin Rejžek, Michal Sochor, Martin Svátek, Jakub Kvasnica, Zuzana Egertová, Joan T. Pereira, Reuben Nilus and Martin Dančák. 2018. Two New Species of Thismia subsect. Odoardoa (Thismiaceae) from Borneo. Plant Ecology and Evolution. 151(1); 110-118. DOI: 10.5091/plecevo.2018.1387
