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| Gastrodia microchila Hroneš, in Hroneš, Sochor, Uvírová, bin Pandai, Jaafar, Sukri et Dančák, 2025. |
Abstract
A new orchid species, Gastrodia microchila is described and illustrated. The species was found in a mixed dipterocarp forest in the Belait district, Brunei Darussalam, northern Borneo in 2024. It is distinct from most Gastrodia species in western Malesia by its small lip and column, and presence of the smooth cushion-like tissue on the inner side of lateral sepals. Gastrodia microchila is only the second species of Gastrodia recorded for Brunei Darussalam and the seventh known species for Borneo. A determination key for all Gastrodia species occurring in western Malesia is also provided.
Key words: Borneo, endemic species, holomycotrophic orchid, Malesia, mycoheterotrophy, tribe Gastrodieae
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| Gastrodia microchila Hroneš A habit of flowering plant B detail of inflorescence with bracts C dissected synsepalum with free parts of sepals and petals D flower viewed from above E flower viewed from below F front view of flower G lip H column A–H from Hroneš 2024/4 (Illustration V. Blažek). |
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| Gastrodia microchila Hroneš A habit of flowering plant B fruiting plant with capsules on elongated pedicels C detail of inflorescence with side view of flower D front view of flower E inflorescence viewed from above F flower viewed from below with connate and free part of lateral sepals, and ovary G dissected synsepalum showing minute petals and cushion-like smooth tissue on the internal side of sepals H part of the stem with leaf I tuber A–I from Hroneš 2024/4 (Photo M. Hroneš). |
Gastrodia microchila Hroneš, sp. nov.
Diagnosis. Gastrodia microchila is similar to G. holttumii Carr from Peninsular Malaysia but differs by narrower cylindrical rhizome without distinct nodes (vs. robust, distinctly noded), flowers 8.5–9.0 mm wide, narrowly open (vs. 9.0–11.0 mm wide, widely open), free part of lateral and dorsal sepals oblong triangular to broadly triangular, up to 4.5 × 5.0 mm (vs. elliptic to oblong elliptic, 6.0–7.0 × 3.0–5.0 mm), free part of petals indistinct, ca. 0.7 × 0.6 mm, elliptic (vs. 1.0–2.0 × 0.7–1.0 mm, ovate), hypochile 2.0 × 2.0 mm, broadly oblong-orbicular (vs. 2.0 × 1.5 mm, oblong-ovate) and stelidia longer than anther cap (vs. subequal to anther cap).
Etymology. The name is derived from the Latin micro- = small and -chilum = lip, referring to the size of the lip, which is among the smallest in Gastrodia species in western Malesia.
Michal Hroneš, Michal Sochor, Alena Uvírová, Azlan bin Pandai, Salwana Jaafar, Rahayu S. Sukri and Martin Dančák. 2025. Gastrodia microchila (Orchidaceae, Epidendroideae), A New Species from Brunei Darussalam. PhytoKeys. 256: 1-11. DOI: doi.org/10.3897/phytokeys.256.149020