Wednesday, February 5, 2025

[Botany • 2024] Bulbophyllum bonjolianum (Orchidaceae: Epidendroideae: Bulbophyllinae) • A New Species of section Macrocaulia from Sumatra, Indonesia


 Bulbophyllum bonjolianum Yudistira, Candra & Mustaqim, 

in Yudistira, Candra et Mustaqim, 2024. 

Bulbophyllum bonjolianum Yudistira, Candra & Mustaqim, a member of section Macrocaulia, is described here based on a specimen collected from the mountains of West Sumatra. It is similar to B. tristriatum Carr. and B. pyridion J.J.Verm. but differs in the morphology of the dorsal sepal, petal and labellum. A key to B. bonjolianum and morphologically similar species is presented.

Keywords. Endemic, epiphyte, Malesia, orchids, taxonomy


 Bulbophyllum bonjolianum Yudistira, Candra & Mustaqim.
 A. Plant habit with inflorescence. B. Flower top view. C. Median sepal, abaxial view. D. Median sepal, adaxial view. E. Lateral sepal, abaxial view. F. Lateral sepal, adaxial view. G. Petal, abaxial view. H. Petal, adaxial view. I. Labellum, lateral view. J, K. Labellum, abaxial and adaxial surface. L. Column stelidium. M. Anther cap, adaxial view. N. Anther cap, abaxial view. O. Pollinarium.
Drawing by Yuanito Eliazar.

 Bulbophyllum bonjolianum Yudistira, Candra & Mustaqim.
A. Plant habit. B. Inflorescence. C, D. Flower, lateral view, with close-up view showing basal node of the pedicel. E. Flower, front view without median sepal. F. Flower, view from above. G. Median sepal, abaxial and adaxial views. H. Petal, abaxial and adaxial views. I. Lateral sepal, abaxial, adaxial and side views. J. Labellum, adaxial, abaxial and side views. K. Column with stelidia, side view. L. Column stelidia, front view.
 ab = abaxial, ad = adaxial, sv = side view. (Photos: Y.R. Yudistira)

Bulbophyllum bonjolianum Yudistira, Candra & Mustaqim, sp. nov.

Bulbophyllum bonjolianum is morphologically similar to B. tristriatum Carr. and B. pyridion J.J.Verm., but differs in the dorsal sepals abruptly tapering from the middle upwards (vs gradually narrowing), pentagonal petal (vs elliptic-(ob)-ovate in B. tristriatum and elliptic in B. pyridion), and longer labellum (6.8–7 mm vs 3.5–5 mm in B. tristriatum and c. 3.2 mm long in B. pyridion) with the proximal adaxial surface coarsely papillose (vs smooth). The species is also similar to the Peninsular Malaysian species B. hodgsonii M.R.Hend., but the new species differs in its dorsal sepals abruptly tapering from the middle upwards (vs gradually narrowing), lateral sepals with 3 veins (vs 5), and the coarsely papillose adaxial surface of the labellum in the lower proximal part (vs smooth).

Etymology. The species is named in honour of Tuanku Imam Bonjol, a national hero of Indonesia from West Sumatra Province.   


Yudistira, Y.R., Candra, R. and Mustaqim, W.A. 2024. A New Species of Bulbophyllum (Orchidaceae: Bulbophyllinae) section Macrocaulia from Sumatra, Indonesia. Gardens' Bulletin Singapore. 76(1); 251 - 258.