Thismia

Guzmán-Guzmán, Santiago & Plata-Torres, Angelo, 2023, A flower in paradise: citizen science helps to discover Thismia paradisiaca (Thismiaceae), a new species from the Chocó Biogeographic region in Colombia, Phytotaxa 603 (1), pp. 27-42 : 38-39

Key to the species of Thismia subgen. Ophiomeris

Thismia iguassensis ( Miers 1847: 329) Warming (1901: 182) is excluded due to lack of the necessary morphological information. This species was described by Miers (1847) based only on a single fruiting specimen, and has never been recollected since then. In the absence of data of floral structure, it is impossible to include it in the key (see Maas et al. 1986).

1. Underground part vermiform; stem terete with leaves distributed lenghtwise; stamen connective usually entire (only basally lobed in T. ribeiroi ); stigma with basal lobes (absent in T. caudata ) ........................................................................... 2 (sect. Pyramidalis )

- Underground part tubercular; stem sulcate; stamen connective basally and/or apically lobed; stigma without basal lobes .............8

2. Tepals homomorphic, inserted almost at the same level; stamen connective basally lobulated; basal lobe of stigma divaricate ....... ................................................................................................................................................................................... Thismia ribeiroi

- Tepals heteromorphic, inserted at different levels; stamen connective basally without lobes; basal lobe of stigma incurved toward style or absent .....................................................................................................................................................................................3

3. Inner tepals free ..................................................................................................................................................................................4

- Inner tepals connate............................................................................................................................................................................5

4. Inner tepals non-appendaged; stigma apex truncate................................................................................................... Thismia singeri

- Inner tepals each with bowl-shaped appendage; stigma apex trilobed............................................................... Thismia fungiformis

5. Inner tepals each with linear-triangular appendage with, subclavate apex; style apex covered by glandular spots; stigma apex acute, basal lobe absent....................................................................................................................................................... Thismia caudata

- Inner tepals non-appendaged; style apex glabrous; stigma apex acute or trilobed, base with basal lobe incurved towards style....... ............................................................................................................................................................................................................6

6. Outer surface of hypanthium smooth; inner surface of hypanthium transversely with a lobed and striated laminar projections; outer tepals lanceolate, twisted; inner tepals forming a slightly triangular mitre without foveae.............................. Thismia petasiformis

- Outer surface of hypanthium ornamented; inner surface of hypanthium transversely with striated laminar projections; outer tepals orbicular or ovate, straight; inner tepals forming a hexagonal or subglobose mitre with foveae ......................................................7

7. Outer tepals ovate, margin flat; mitre hexagonal, outer surface ornamented with six triangles foveate on top; outer surface of ovary keeled, verrucose .............................................................................................................................................. Thismia melanomitra

- Outer tepals orbicular, margin revolute; mitre subglobose, outer surface ornamented with irregularly foveate on top; outer surface of ovary flat, smooth............................................................................................................................. Thismia pseudomelanomitra

8. Flower pedicellate; stamen filament linear; stamen connective basally bilobed, apically entire; interstaminal lobes absent; peduncle accrescent ..................................................................................................................................... Thismia hyalina (sect. Myostoma )

- Flower sessile to subsessile; stamen filament laminar; stamen connective basally and apically bilobed (apically entire in T. mantiqueirensis ); interstaminal lobes present or absent; peduncle non-acrescent ..............................................9 (sect. Ophiomeris )

9. Inner tepals non-appendaged and apically not tapering into a cauda....................................................... Thismia espirito-santensis

- Inner tepals appendaged or apically tapering into a long linear-filiform cauda...............................................................................10

10. Inner tepals appendaged ......................................................................................................................................... Thismia saulensis

- Inner tepals apically tapering into a long linear-filiform cauda .......................................................................................................11

11. Hypanthium campanulate.................................................................................................................................................................12

- Hypanthium strongly gibbous or tubular to slightly gibbous...........................................................................................................13

12. Hypanthium base without internal foveae; stamen connective with entire apex ........................................ Thismia mantiqueirensis

- Hypanthium base with internal foveae; stamen connective with bilobed apex....................................................... Thismia glaziovii

13. Hypanthium tubular to slightly gibbous ...........................................................................................................................................14

- Hypanthium strongly gibbous ..........................................................................................................................................................15

14. Outer surface of hypanthium ornamented longitudinally by six double lamellae; annulus orifice surrounded by a ring of six foveae; interstaminal lobes globose; stigma entirely covered by papillae ........................................................................ Thismia prataensis

- Outer surface of hypanthium unornamented, smooth; annulus orifice not surrounded by foveae; interstaminal lobes triangular; stigma proximally covered by papillae, distally covered by tufts of trichomes.................................................. Thismia janeirensis

15. Hypanthium with a longitudinal slit resembling a spur; interstaminal lobes absent; margin of outer tepals lacerate, slightly toothed to ciliate; stamen connective with slightly mammiform, inconspicuous basal lobes............................................. Thismia calcarata

- Hypanthium without longitudinal slits; interstaminal lobes present; margin of outer tepals entire; stamen connective with filiform, linear or falcate, conspicuous basal lobes.........................................................................................................................................16

16. Thecae not fused, dehiscence line linear; distal portion of the connective covered by a tuft of trichomes .....................................17

- Thecae fused, dehiscence line hippocrepiform; connective glabrous ..............................................................................................18

17. Outer tepals reflexed to spreading; each segment of annulus ornamented by three prominent crests: bilobed outer crest, and entire middle and inner crests; stamens homomorphic; thecae inserted into the middle of the stamen connective; stigma cylindrical; pollen size greater than 25µm ............................................................................................................................ Thismia panamensis

- Upper outer tepal incurved, lateral outer tepals declinate and slightly twisted laterally outside; each segment of annulus ornamented by three entire prominent crests; stamens dimorphic; thecae inserted into the upper part of the stamen connective; stigma conical; pollen size less than 25µm.................................................................................................................................. Thismia paradisiaca

18. Stigma obovoid, covered by trichomes of uniform shape and size......................................................................... Thismia andicola

- Stigma conical or ovoid, covered proximally by short trichomes or papillae (0.1–0.3 mm long) and distally or towards the margins by long trichomes (0.3–1 mm long) .................................................................................................................................................19

19. Outer tepals cordate at base; annulus composed of a disc ornamented by six prominent contiguous triangular lobes forming a star, densely pilose ............................................................................................................................................................ Thismia cordata

- Outer tepals truncate at base; annulus composed of three connate segments, each segment ornamented with three prominent crests, arranged parallel to the orifice, glabrous..........................................................................................................................................20

20. Inner tepals with swollen apex of cauda........................................................................................................... Thismia luetzelburgii

- Inner tepals with apex of cauda not swollen ....................................................................................................................................21

21. Inner tepals 10–15 mm long; each segment of annulus ornamented by three prominent entire crests.............. Thismia macahensis

- Inner tepales 17.2–55.5 mm long; each segment of annulus ornamented by three prominent crests: bilobed outer crest, and entire middle and inner crests........................................................................................................................................... Thismia variabilis