Stereochilus, Lindley, 1858

Chowlu, Krishna & Rao, A. Nageswara, 2020, Stereochilus arunachalensis, a new orchid species of Orchidaceae (Epidendroideae: Vandeae: Aeridinae) from Arunachal Pradesh, India, Phytotaxa 433 (2), pp. 177-180 : 178-179

With this new species, the total number of Stereochilus species has increased to eight. An identification key has been provided below for all these species.

1. Rachis and pedicellate ovary prominently glandular-pubescent ........................................................................................................ 2

- Rachis and pedicellate ovary glabrous or slightly pubescent............................................................................................................. 5

2. Midlobe of lip embracing the lateral lobes with lower half portion................................................................................................... 3

- Midlobe of lip continuous with lateral lobes, not embracing lateral lobes ........................................................................................ 4

3. Sepals glandular hairy outside .................................................................................... S. erinaceous ( Myanmar, Thailand, Vietnam) - Sepals glabrous outside .............................................................................................................................. S. arunachalensis ( India )

4. Spur tubular, rounded at tip ..................................................................................................................... S. hirtus ( India , Myanmar)

- Spur flattened, minutely bilobed at tip .............................................................................................. S. brevirachis ( China, Vietnam)

5. Lateral lobes of lip with acute tips ................................................................................................................................................... 6

- Lateral lobes of lip with rounded tips................................................................................................................................................. 7

6. Midlobe of lip warty.......................................................................................................................... S. ringens ( India , Philippines?)

- Midlobe of lip glabrous, not warty.......................................................................................................... S. pachyphyllus ( Thailand)

7. Leaves distinctly V-shaped in cross section, rounded at apex............................................ S. dalatensis ( China, Thailand, Vietnam)

- Leaves ellipsoid in transverse section with groove dorsally, unequally obtusely bilobed at apex..................... S. laxus ( Myanmar)