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| Gastrodia longiflora Suetsugu |
Gastrodia Brown (1810: 330; Gastrodieae, Epidendroideae) is a mycoheterotrophic orchid genus distributed in temperate and tropical regions of Asia, Oceania, Madagascar, and Africa (Cribb et al. 2010, Hsu & Kuo 2010, Suetsugu et al. 2018). It is characterized by fleshy tubers, absence of normal leaves, united sepals and petals and two mealy pollinia without caudicles (Cribb et al. 2010, Hsu & Kuo 2010, Hsu et al. 2012, Suetsugu et al. 2018).
Several recent studies have re-examined the diversity of Gastrodia in many Asian countries. Consequently, the genus
comprises more than 100 species, making it the most species-rich mycoheterotrophic genus (Suetsugu et al. 2018a,b,
Suetsugu 2019). However, species diversity of Gastrodia likely remains underestimated due to its brief flowering season
and dwarf habit. As anticipated, an unknown Gastrodia species was discovered during a recent botanical survey on Ishigaki
Island, Japan. A remarkably long, narrow perianth tube shows a close affinity to G. nipponica (Honda, 1932: 168) Tuyama
(1939: 4). Accordingly, this plant is described here as a new species and a detailed morphological account is provided.
Keywords: Monocots, Orchidaceae, Epidendroideae, Gastrodieae
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| Gastrodia longiflora Suetsugu (from the holotype). A. Habit. B. Flattened perianth tube. C. Flower (side view, dorsal view and ventral view). D. Column and lip. E. Lip. F. Free portions of lateral sepal and petal. G. Anther cap. H. Column (side view, dorsal view and ventral view). Size bars: A–C, 1 cm; D–F, H, 5 mm; G, 2 mm. |
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| Gastrodia longiflora Suetsugu from the type locality. A. Flowering plants, view from above. B. Flowering plants, side view. C. Flowers, side view. D. Flower, front view. Photographed by Hiroshi Kazui. |
Gastrodia longiflora Suetsugu, sp. nov.
Gastrodia longiflora is similar to G. nipponica but differs by its perianth tube that is relatively narrower for its length and hemiellipsoid anther cap.
Distribution and phenology:— Restricted to the type locality, where dozens of flowering individuals occur in a dense
forest dominated by Castanopsis sieboldii (Makino, 1909: 141) Hatusima (1971: 223). Flowering was observed from mid-February to mid-March, and fruiting from late-March to early-April.
Kenji Suetsugu. 2021. Gastrodia longiflora (Orchidaceae: Epidendroideae: Gastrodieae), A New Mycoheterotrophic Species from Ishigaki Island, Ryukyu Islands, Japan. Phytotaxa. 502(1); 107–110. DOI: 10.11646/phytotaxa.502.1.9
