Thismia

Suetsugu, Kenji, Tsukaya, Hirokazu, Tagane, Shuichiro, Suddee, Somran, Rueangruea, Sukid & Yahara, Tetsukazu, 2017, Thismia brunneomitroides (Thismiaceae), a new mycoheterotrophic species from southern Thailand, Phytotaxa 314 (1), pp. 103-109 : 105

Key to the species of Thismia in the Thai-Malay Peninsula (modified after Chantanaorrapint et al. 2016)

1. Inner perianth lobes free, spreading or erect......................................................................................................................................2

- Inner perianth lobes connate at the apex to form a mitre.................................................................................................................10

2. Perianth lobes equal in length and size...............................................................................................................................................3

- Perianth lobes unequal in length and size, inner ones larger..............................................................................................................9

3. Appendages of perianth lobe hairy.................................................................................................................................... T. chrysops

- Appendages of perianth lobe glabrous...............................................................................................................................................4

4. Stem several. Flowers 4–6................................................................................................................................................ T. racemosa

- Stem simple. Flowers 1–3..................................................................................................................................................................5

5. Perianth lobes narrowly triangular or linear-lanceolate, flat, without filiform appendages................................................. T. fumida

- Perianth lobes triangular, with filiform appendages on the outer surface..........................................................................................6

6. Leaves and bracts bearing glandular hairs on dorsal surface ........................................................................................ T. grandiflora

- Leaves and bracts glabrous.................................................................................................................................................................7

7. Perianth without transverse bars inside. Apex of stamens with 2 teeth......................................................................... T. claviformis

- Perianth with transverse bars inside. Apex of stamens with 1 or 3 appendages................................................................................8

8. Apex of stamens with 1 thick-filiform appendage. Perianth lobes with appendages more than 15 mm long ......................... T. alba

- Apex of stamens with 3 thick-filiform appendages. Perianth lobes with appendages up to 10 mm long............................. T. aseroe

9. Stigma lobes acuminate.................................................................................................................................................. T. arachnites

- Stigma lobes truncate ......................................................................................................................................................... T. javanica

10. Underground part vermiform. Top of the mitre with 3 fovea........................................................................................... T. nigricans

- Underground part coralliform. Top of the mitre without 3 fovea.....................................................................................................11

11. Top of the mitre with 3 slender claviform appendages .................................................................................................... T. clavigera

- Top of the mitre lacking claviform appendages..............................................................................................................................12.

12. Top of the mitre with 3 very short acute projections. Apex of stamens obtuse to shallowly 3-lobed. Stigma ca. 0.5 mm long.......... ........................................................................................................................... T. clandestina sensu Chantanaorrapint et al. (2015)

- Top of the mitre with 3 longer acute projections. Apex of stamens 2-lobed, rarely 3-lobed. Stigma ca. 1.2 mm long ....................... ............................................................................................................................................................................ T. brunneomitroides