Thismia betung-kerihunensis Tsukaya & H. Okada, 2012

Tsukaya, Hirokazu & Okada, Hiroshi, 2012, A New Species of Thismia (Thismiaceae) from West Kalimantan, Borneo, Systematic Botany (Basel, Switzerland) 37 (1), pp. 53-57 : 56

Thismia betung-kerihunensis Tsukaya & H. Okada sp. nov.

— TYPE: INDONESIA. West Kalimantan: Betung Kerihun National Park , near Sungai (River) Tobong Kopang , ca. 228 m altitude, 00 54 0 51.1 00 N, 113 40 0 20.7 00 E, on a slope under tropical rain forest (lower hill forest), mainly composed of Dipterocarpaceae , December 27, 2010, H. Okada, H. Nagamasu, & H. Tsukaya HT1012 (holotype: BO; isotype: TI, preserved in 50% ethanol) .

Herbae terrestris, erectae. Thismia clavigera (Becc.) F. v. M. affinis, sed corolla caerulea, lobi affixi appendicis cuculatae conspicuae, connectivum staminis absque oxysegmentum trigonus, glans rectangularis (non semiglobosa) differt.

Terrestrial, achlorophyllous herb, mycotrophic. Stems erect, simple, bearing 1–2 flowers, bluish white at young stage, turning pale purple, then pale brown, 3–4 cm long. Roots coralliform, brown, tips whitish. Leaves spirally arranged, lanceolate, to 5 mm long, pale whitish blue to pale brown. Floral bracts to 8 mm long, 2 mm wide, lanceolate, acuminate. Flowers 2 cm long, excluding the tentacles; basal perianth tube white with indigo and brown with 12 nerves at young stage, which turns pale brown with purple-dark blue nerves later, 1.1–1.2 cm long, glabrous; throat margin thickened; outer perianth lobes deltoid, minute; inner perianth mitriform with clawed lobes, incurved, centrally adnate to form a dome-shaped mitre with three wide windows, midveins riblike, bearing three hood-like accessory lobes at the tip and three slender claviform appendages. The mitre is blue-green, 4.4–6.9 mm long, except for the ca. 15-mm-long claviform appendages, which are pale blue at the base and tinged with orange at the tip at the young stage. Stamens 6, borne on the thickened margin of the perianth-tube, curved downwards, filaments short, ribbon-shaped, free; connective broad with a quadrangular wing, hairy, connate to form a tube; anther thecae oblong, adnate, seen on the adaxial side of the connectives, 0.9–1.1 mm long; gland present near the apex on the line of fusion between the connectives, rectangular, 0.6–0.8 mm long, 0.2 mm wide. Stigmas free, ca. 1.4 mm long. Ovary 1.3–2.8 mm long and cup-shaped. Fruit not seen.

Note— We collected three individuals in a less than 10 m + 10 m square in the locality. No other individual was discovered in neighboring places during the botanical survey, suggesting that this species is rare even in the Betung-Keruhin National Park, although the type locality is under protection. Areas around the type locality were rich in mycoheterotroph species, such as four Burmanniaceae (one species of Gymnosiphon and three Burmannia ), two Polygalaceae (two Epirixanthes ), two Triuridaceae (two Schiaphila), and seven Orchidaceae (three Lecanorchis and so on) species, but none co-habited with this species.