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Begonia mattampensis in Reinwardtia 18(1): 23. 2019
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Diagnosis
- This species has a creeping stem, which is rare in Begonia section Petermannia. Of the Sulawesi species in Begonia sect. Petermannia with creeping stems (Begonia gemella Warb. ex L.B.Sm. & Wassh., B. heteroclinis Miq. ex Koord., and B. flacca Irmsch.) it is most similar to B. flacca, but differs from it in its leaf shape (elliptic to suborbicular with entire margin and rounded apex vs ovate to elliptic with serrate or biserrate to shallowly lobed margin and acuminate apex), male partial inflorescences arranged in strongly compressed monochasia (vs simple, elongate monochasia), fewer stamens (24–27 vs 52–62) and larger and differently shaped fruit (ovoid, 10–17 × 8–9 mm, widest point of fruit wing subapically to middle of the seed-bearing part, up to 13 mm wide vs ellipsoid, obovoid or cylindrical, 10–12 × 4.5–6.5 mm, widest point at the apex or subapically, to 8 mm wide). (Ardi, W.H. & Thomas, D.C. 2019. A new species of Begonia (Begoniaceae) from South Sulawesi, Indonesia, and an augmented description of Begonia bonthainensis in Reinwardtia 18(1): 19-26.. http://doi.org/10.14203/reinwardtia.v18il.3691)
Description
- Perennial, monoecious herb with creeping stems, rooting at the nodes when in contact with the substrate, up to ca. 25 cm long, sparsely hairy with white hairs up to ca. 2 mm long. Stem creeping, internodes 1.5−4 cm long, greenish. Leaves alternate; stipules persistent, 12−13 × 5−8 mm, ovate, with an abaxially slightly prominent midrib projecting up to 5 mm at the apex, greenish-reddish, glabrous; petioles 8.5−18.5 cm long, terrete, red, sparsely to moderately hairy; lamina 6.5–12.5 × 5–10 cm, asymmetric, elliptic to suborbicular, base cordate and lobes slightly over-lapping, apex rounded, margin entire and undulate in the larger leaves, adaxial surface green to dark green, glabrous, abaxial surface reddish, glabrous; primary veins 5–7, actinodromous, secondary veins craspedodromous. Inflorescences: protogy-nous; female inflorescences 1-flowered (female flowers solitary), basal to male inflorescences, peduncles ca. 1 mm long, pale green, glabrous; male inflorescences composed of up to 7 partial inflorescences, each partial compressed monochasial with up to 5 flowers, peduncles 2.5–5 cm long, pink, glabrous; bracts 5−10 × 3−5 mm, ovate, midrib slightly prominent projecting up to 1 mm at the apex. Male flowers: pedicels 17–20 mm long, white-pinkish, glabrous; tepals 2, white and tinged pink at the margin, 9–11 × 11–14 mm, broadly ovate, base slightly cordate, margin entire, apex rounded; androecium of 24–27 stamens, yellow, filaments up to ca. 1.5 mm long, fused at the base for ca. 1 mm, anthers up to 1.5 mm long, obovate, dehiscing through unilaterally positioned slits that are ca. 1/2 as long as the anthers. Female flowers: pedicels 4–9 mm long, pale green, glabrous; tepals 5, subequal, white or white tinged pink, 10–14.4 × 6.5–12 mm, elliptic, margin entire, apex rounded; ovary (without wings) 8–11.5 × 7.5–8.5 mm, ovoid, sometimes beaked at the apex, pale green, wings 3, subequal to unequal, one wing larger than the other two, base rounded, apex cuneate, up to 8 mm long at the widest point (subapically to middle of the ovary), style up to 4 mm long, basally fused, 3–branched, each stylodium bifurcate in the stigmatic region, stigmatic surface a spirally twisted papillose band, orange. Fruit: peduncle ca. 1 mm long; pedicels 4−6 mm long; seed-bearing part 10−17 × 8−9 mm (excluding the wings), ovoid, glabrescent, dehiscent, splitting along the wing attachment, wings subequal to slightly unequal, base rounded, apex subtruncate to rounded, up to 13 mm long at the widest point (subapically to middle of the seed-bearing part). Seeds barrel-shaped, ca. 0.3‒0.4 mm long. (Ardi, W.H. & Thomas, D.C. 2019. A new species of Begonia (Begoniaceae) from South Sulawesi, Indonesia, and an augmented description of Begonia bonthainensis in Reinwardtia 18(1): 19-26.. http://doi.org/10.14203/reinwardtia.v18il.3691)
Habitat
- Growing on limestone walls and cave entrances, at low elevation (ca. 5‒10 m). (Ardi, W.H. & Thomas, D.C. 2019. A new species of Begonia (Begoniaceae) from South Sulawesi, Indonesia, and an augmented description of Begonia bonthainensis in Reinwardtia 18(1): 19-26.. http://doi.org/10.14203/reinwardtia.v18il.3691)
Conservation
- Critically Endangered CR B1ab(iii)+B2ab(iii). Begonia mattampensis is known from only three collections from the Pangkadjene Karst (Mattampa karst). The karst area is not legally protected, and currently the type locality is part of a tourist attraction (Dufan Mattampa waterpark). In combination with the very small EOO and AOO (4 km2), this indicates that the species should be considered Critically Endangered. (Ardi, W.H. & Thomas, D.C. 2019. A new species of Begonia (Begoniaceae) from South Sulawesi, Indonesia, and an augmented description of Begonia bonthainensis in Reinwardtia 18(1): 19-26.. http://doi.org/10.14203/reinwardtia.v18il.3691)
Notes
- Begonia mattampensis is very distinct among the creeping species from Sulawesi or the Mollucas. The differences between B. flacca are discussed in the diagnosis above. Begonia mattampensis also has some similarities with B. siccacaudata J.Door. (Doorenbos, 2000), which is endemic to the Maros karst in close proximity to the type location. Both species show solitary female flowers and subumbellate male partial inflorescences. However, Begonia mattampensis has a creeping stem with much longer internodes (vs stem thickened and tuberlike with internodes only up to 3.5 mm long), longer petioles (8.5‒18.5 cm vs up to 5 cm), thick and coriaceous leaves (vs thin and papery), and shorter fruit pedicels (4‒6 mm vs 8‒10 mm). (Ardi, W.H. & Thomas, D.C. 2019. A new species of Begonia (Begoniaceae) from South Sulawesi, Indonesia, and an augmented description of Begonia bonthainensis in Reinwardtia 18(1): 19-26.. http://doi.org/10.14203/reinwardtia.v18il.3691)