Gastrodia

Key to species of Gastrodia View in CoL in Thailand

1. Labellum adnate to synsepal below for 1/2 or most of its length….......................................... 2

1. Labellum not adnate to synsepal…................. 3

2. Flowers white or pinkish-white; floral tube cylindric; labellum ornamented by 2 linear-oblong calli near base, apex fimbriate …....................................................... G. fimbriata View in CoL

2. Flowers dark pinkish-brown; floral tube campanulate; labellum without calli or keels, apex entire…............................ G. phangngaensis View in CoL

3. Lateral sepals only connate at the base; labellum usually more than 8 mm long ......... G. javanica View in CoL

3. Lateral sepals connate for most of their length; labellum usually more less 8 mm long.........…4

4. Flowers pale brown…...................................... 5

4. Flowers white, pinkish-white or white cream ..... 6

5. Inflorescence an elongate raceme with loosely arranged flower; floral bracts persistent; sepals almost equally joined into floral tube ............................................................ G. punctata View in CoL

5. Inflorescence a condensed raceme, subumbellate in appearance; loral bracts caducous; sepals unequally joined into floral tube................................................... G. verrucosa View in CoL

6. Inflorescence an elongate raceme with loosely arranged flower; sepals equally joined into floral tube, sepal lobes erose to laciniate ................................................................. G. exilis View in CoL

6. Inflorescence a strongly condensed raceme with subdensely arranged flowers, subumbellate in appearance; sepals unequally joined into floral tube, sepal lobes subentire ............................. 7.

7. Floral tube slightly verrucose towards apex, otherwise smooth; lateral sepals fused for 1/2 their length...................................... G. albidoides View in CoL

7. Floral tube distinctly striate and verrucose throughout; lateral sepals fused for 1/4–1/3 their length.......................................... G. theana View in CoL