Tridactyle pentalobata P.J.Cribb & Stévart

Stévart, T., & Cribb, P. (2004). Five New Taxa of Tridactyle (Orchidaceae) from West Central Africa. Kew Bulletin, 59(2), 195-205. doi:10.2307/4115850

Conservation

Known only from the type locality, which is now included in the Crystal Mountains National Park. It is probably not endangered.

Distribution

Endemic to Monts de Cristal (Gabon).

Ecology

Primary forest; 465 m. Epiphyte at 25 m in the middle part of the canopy.

Morphology General Habit

Epiphytic herb; stem more than 30 cm long, 6 - 7 mm in diameter, pendulous

Morphology Leaves

Leaves more than 6, imbricate, narrowly ovate-elliptic, twisted at base to lie in one plane, thin-textured, lower face keeled, 11.3 - 13.5 x 1.9 - 2.3 cm, unequally roundly bilobed, lobes 0 - 5 mm, articulate at the base to a sheathing leaf base

Morphology Reproductive morphology Flowers

Flowers distichous, green to yellow; pedicel and ovary 4 x 2 mm; bracts amplexicaul, enclosing the rachis and the pedicel, 2.5 x 2 mm

Morphology Reproductive morphology Flowers Calyx

Dorsal sepal convex, oblong, apiculate, 4 x 2.2 mm, thickened, trinerved Lateral sepals oblong, acute, 5.8 x 2.1 mm, trinerved, thickened on outer face, slightly united at the base

Morphology Reproductive morphology Flowers Column

Column 1 mm long.

Morphology Reproductive morphology Flowers Corolla

Petals 4 x 1.8 mm, narrowly oblong, acute, trinerved, margins erose, thickened on outer face Lip oblong, trilobed in the upper part, 4 x 3.2 mm, with two distinct triangular auricles at mouth of the spur, 0.8 mm long; side lobes transversally oblong, very short, 0.5 x 1 mm; midlobe triangular, acute, I x 1 mm long, thickened downward; spur straight, distinctly inflated toward the apex, apex obtuse, 9 x 0.8 - 1 mm

Morphology Reproductive morphology Inflorescences

Inflorescence 3.4 - 5.3 cm, borne opposite the leaves, up to 11-flowered; rachis quadrangular to semi-terete, slightly papillose

Note

Tridactyle pentalobala is a distinctive species with a lip rather similar to that of T. tridentata, but it differs from that species in having dorsiventrally flattened leaves, longer inflorescences and a spur that is markedly inflated. It can be compared with T. gelllilii (De Wild.) Schltr., but that has long lacerate side lobes to the lip and with T. truncatiloba Summerh. which possesses much larger flowers (Summerhayes 1948). This species is named after the shape of the lip, which appears five-lobed with the two distinct basal auricles and a trilobed apex.

Phenology

Flowering in April.

Type

Gabon, Mont Mbilan, Stivart 1394 (holotypus BR).