Indonesia. West Papua, Mokwan, Arfak Mountains, 1700–1900 m, August 16, 2016, Xiaohua Jin 17434 (holotype, BO; isotype, PE).

Bulbophyllum papuaense is close to Bulbophyllum tortuosum and B. muscohaerens but differs from them by having rhizome and pseudobulbs covered with papillose scales, caudate and ciliate petals, linear and ciliate lip which curve at the tip.

Figure 1. 

Habit of Bulbophyllum papuaense.

Epiphytic herb. Rhizome slender, creeping or pending with spreading roots, ca. 0.4 mm in diameter, brown, warty. Pseudobulbs elliptic, fleshy, ad-pressed to the stem, ca. 2.2 × 1.0 mm, with a long membranous sheath at base, usually 1-leaved. Leaf ca. 14 × 6.0 mm, elliptic to oval, entire, middle vein concave, apex mucronate, subsessile, young leaves green then turning reddish purple. Inflorescence solitary, usually 1-flowered, peduncle slender and short, ca. 1 mm long, base covered with long bract. Bracts tubular at base and caudate, 3–5 mm long. Flowers small, reddish purple, lateral sepals connate along their margins, together forming a somewhat boat-shaped structure, ca. 4.2 × 3.0 mm, margins entire, ciliolate in the proximal 1/2 from the base; median sepal oblong, apex attenuate to acuminate, ca. 5.5 × 2.0 mm, margin entire with obvious ciliate, 3-veined; petals much smaller than sepals, triangular and caudate, ca. 2.7 mm long, 1-veined, ciliate, apex contract to linear (caudate) and nearly 3 times as long as the basal part, margins with minutely white hairs; lip linear, recurved, dark reddish purple, ca. 2.6 mm long, with short white hairs, apex slightly widened with long and white hairs, a small triangular protuberance at base. Column white, including stelidia ca. 1.2 mm long, stelidia triangular, ca. 0.2 mm long, acute, with triangular and acute tooth along the upper margin; column foot 1 mm long; mentum cylindric, conspicuous, ca. 1 × 0.5 mm; pollinia 2.

Figure 2. 

Close-up of flowers of Bulbophyllum papuaense.

Bulbophyllum papuaense was discovered in broad-leaved, evergreen montane forest in Mokwan, West Papua. Bulbophyllum papuaense is epiphytic on trunks or shrub in humid and shady areas in montane forest. Plants are tiny and grow usually with moss. Our observation indicated that it was in full bloom in August. Bulbophyllum papuaense is only known from the type locality.

The tropical montane rain forest is well protected in Mokwan region. However, the rain forest is very difficult to reach due to poor transportation. Our examination in BO and Herbarium of Universitas Papua (Manokwari) did not find other collections of this species. Therefore, this new species is currently considered as DD.

The name derives from the Papua, where the new species was discovered.

Bulbophyllum papuaense belongs to sect. Oxysepala which is often characterized by 1-flowered inflorescence, lateral sepals connate, basal node of pedicel near at same level with the attachment of floral bract (Vermeulen et al. 2015). Bulbophyllum papuaense is a distinctive species in sect. Oxysepala and easily differs from its relatives by its morphological characters, such as the rhizome with warty scales, caudate and ciliate petals, linear lip recurve and with white hairs.

Figure 3. 

Color drawing of Bulbophyllum papuaense A Plants B front view of flower C lateral view of flower.