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| Begonia willemii Ardi, Girm. & D.C.Thomas, in Ardi, Girmansyah, Zulfadli et Thomas, 2021. |
Abstract
A new species of Begonia sect. Petermannia (Begoniaceae), Begonia willemii Ardi, Girm. & D.C.Thomas, is described from Sulawesi, Indonesia. The species is a calciphile endemic to Sulawesi. It is morphologically similar to Begonia gemella but can be easily differentiated by its smaller leaves, a sparse, bristly indumentum on the adaxial lamina surface, simple monochasial male inflorescences, longer pedicels, fewer stamens and two-tepaled female flower. Its conservation status is provisionally assessed as Near Threatened (NT).
Keyword: Begonia gemella, Begonia manuselaensis, Begonia sidolensis endemic, karst, limestone, Petermannia
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| Begonia willemii Ardi, Girm. & D.C.Thomas A. Habit of Toli-toli population; B. Habit of Batutikar waterfall population; C. Stipule; D. Male flower; E. Androecium; F. Male inflorescence; G. Mixed female-male inflorescence; H. Fruit of Toli-toli population; I. Fruit of Batutikar population; J. Ovary, cross section of middle part. B–G, I, J from WI 415; A, H from ZF 42. (Photos B–G, I, J: W.H. Ardi; A, H: Zulfadly). |
Begonia willemii Ardi, Girm. & D.C.Thomas, sp. nov.
Sect. Petermannia
The creeping growth habit, the relatively small leaf laminas, and the monochasially branching male inflorescences are similar to Begonia gemella Warb. ex L.B.Sm. & Wassh. (1983) from Minahasa, Sulawesi, but B. willemii can be distinguished by a smaller leaf lamina (3–8 × 2.5–6 cm versus 5–9.5 × 4.5–8 cm for B. gemella) with a sparse indumentum of red bristle hairs between the veins on the adaxial surface (versus glabrous), male flowers in simple monochasial cymes (versus thyrses composed of up to 3 monochasial cymes), longer male flower pedicels (2–4 cm versus 1.5–1.8 cm long), fewer stamens (c. 19‒23 versus ca. 75–77), and female flowers consistently with two tepals (versus five tepals).
Distribution. Endemic to Sulawesi (Fig. 2), Gorontalo Province (Gorontalo Regency) and Central Sulawesi Province (Luwuk Banggai and Toli-toli Regencies).
Habitat. Lowland limestone karst forest, disturbed forest, growing vertically on limestone rock, or terrestrially on the base of limestone cliffs, in half to full shade, at 10 to 50 m elevation.
Etymology. This species is named in honour of Willem Jan Jacobus Oswald de Wilde (1936‒2021); a prominent tropical botanist, who has made outstanding contributions to the botanical knowledge of the Flora Malesia region.
Wisnu H. Ardi, Deden Girmansyah, Zulfadli and Daniel C. Thomas. 2021. Begonia willemii, A New Species of Begonia from Sulawesi, Indonesia. Taiwania. 66(3); 374-377. DOI: 10.6165/tai.2021.66.374
