Thismia sect. Ophiomeris (Miers, 1847) Maas & Maas, 1986

Aguilar-Cano, José, Guzmán-Guzmán, Santiago & Lopera-Toro, Alejandro, 2023, Thismia andicola sp. nov. (Thismiaceae): a new species from the northern Andes in Colombia, Phytotaxa 579 (2), pp. 107-116 : 112-113

Key to the species of Thismia sect. Ophiomeris (adapted from Maas et al. 1986)

1. Tepals equal in shape and size, all triangular to ovate, without appendages....................................................... T. espirito-santensis

- Tepals unequal, one outer whorl of shorter triangular to lanceolate tepals and one inner whorl of longer tepals with the proximal portion triangular to lanceolate, gradually tapering into a filiform distal portion or appendage ......................................................2.

2. Annulus continuous ...........................................................................................................................................................................3.

- Annulus segmented, with segments alternating with outer tepals.....................................................................................................5.

3. Floral tube zygomorphic; annulus without papillose zone, ornamented with three rings of ridges.............................. T. macahensis

- Floral tube actinomorphic; annulus with papillose zone, ornamented with a ring of 6 V-shaped ribs or pitted by 6 depressions ...4.

4. Floral tube campanulate; outer surface of floral tube with 12 swellings at base; stigma capitate ...................................... T.glaziovii

- Floral tube urceolate; outer surface of floral tube smooth with 6 double longitudinal lamellae; stigma trilobed .......... T. prataensis

5. Inner tepals appendaged, appendage inserted just below the apex of the laminar portion .............................................. T. saulensis

- Inner tepals without appendage, with the laminar portion tapering into the filiform portion ...........................................................6.

6. Inner tepals with thickened apex of filiform portion.................................................................................................... T. luetzelburgii

- Inner tepals with slender apex of filiform portion.............................................................................................................................7.

7. Floral tube slightly zygomorphic, tubular to slightly urceolate at apex; connective not projecting beyond thecae (supraconnective absent)............................................................................................................................................................................. T. janeirensis

- Floral tube strongly zygomorphic, urceolate; supraconnective present ............................................................................................8.

8. Connective and supraconnective glabrous; sagittate lobes at base of connective ca. 1.3 mm long; stigma obovoid, fully and evenly covered by simple, multicellular uniseriate trichomes..................................................................................................... T. andicola

- Connective and supraconnective pubescent o glabrous; sagittate lobes at base of connective ca. 0.5 mm long; stigma cylindric, proximally papillose and distally with tufts of simple, multicellular uniseriate trichomes........................................... T. panamensis