Gastrodia, Brown, 1810

Hsu, Tian-Chuan, Fanerii, Moffat, Yang, Tsung-Yu Aleck, Pitisopa, Fred & Li, Chia-Wei, 2016, Gastrodia isabelensis and G. solomonensis (Gastrodieae, Epidendroideae, Orchidaceae): two new species representing a new generic record in the Solomon Islands, Phytotaxa 270 (2), pp. 137-145 : 144

Key to the Gastrodia callosa- alliance species:

1. Perianth tube with 5 reddish calli on abaxial surfaces of each sepals and petals....................................................................... G. sui

- Perianth tube with 2 orange to reddish calli on abaxial surfaces of each lateral sepal.......................................................................2

2. Perianth tube 22–28 × 15–20 mm; lip with elliptic mesochile.................................................................................. G. solomonensis

- Perianth tube 9–13 × 7–10 mm; lip with ovate or orbicular-obovate mesochile...............................................................................3

3. Flower cleistogamous; lip with orbicular-obovate mesochile..................................................................................... G. crassipetala

- Flower slightly opening; lip with ovate mesochile.............................................................................................................................4

4. Inflorescence 10–16 cm; sepal lobes broadly ovate to semiorbicular; petal lobes ovate-orbicular; lip with semiorbicular epichiles ....................................................................................................................................................................................... G. isabelensis

- Inflorescence 1–8 cm; sepal lobes broadly ovate to ovate-deltoid; petal lobes ovate to subdeltoid; lip with shortly ligulate epichiles.......................................................................................................................................................................................................5

5. Inflorescence 1–5-flowered; calli inside perianth tube rather large, occupying ca. 2/3 length of lateral sepals; lip 3.5–4.5 mm wide ..................................................................................................................................................................................... G. callosa

- Inflorescence 1–2-flowered; calli inside perianth tube smaller, occupying ca. 1/3 length of lateral sepals; lip 2.5–3.0 mm wide ..... .................................................................................................................................................................................. G. queenslandica