Two new species of Begonia, B. moneta and B. peridoticola (Begoniaceae) from Sabah, Malaysia

Abstract

Background: Mount Kinabalu, reknowned for its high biodiversity and endemism, is a National Park in the State of Sabah on the northern end of the island of Borneo. Every year many visit the higher part of the Kinabalu National Park, while most lowland forests in the Park are under-explored. Two unknown species of Begonia were collected from a peridotic (ultramafic) cliff in the Kinabalu National Park at ca. 400 m elevation.

Results: The two species are named B. moneta C.-I Peng, Rimi & C. W. Lin and B. peridoticola Rimi, C.-I Peng & C. W. Lin. Begonia moneta (sect. Baryandra) is similar to B. gueritziana Gibbs, a widespread species of the same section in Borneo, differing in the peltate (vs. basifixed) leaves and the smaller flower parts. Also, their chromosome numbers are different (B. moneta, 2n = 30; B. gueritziana, 2n = 28). The peltate and succulent foliage of B. moneta is also reminiscent of B. burttii Kiew & S. Julia and B. payung S. Julia & Kiew, both of sect. Reichenheimia, from Sarawak. Begonia moneta is distinct from the two species in having branched (vs. entire) placental lamellae. Additionally, B. moneta differs from B. burttii in having 4 (vs. 5) tepals in pistillate flowers and markedly unequal (vs. equal) fruit wings. Begonia moneta differs from B. payung in the smaller leaves and conspicuously winged (vs. wingless) capsules. Begonia peridoticola (sect. Petermannia) resembles B. punchak Kiew & S. Julia from limestone areas in Kuching Division, Sarawak, differing in the entire leaf margin (vs. distantly dentate), much larger capsular wings (8-11 mm vs. 2-3 mm wide) and yellow, spiral (vs. crimson, U-shaped) styles.

Conclusion: A careful study of the herbarium materials and literature supports the recognition of the two new species. Detailed descriptions, line drawings, color plates, chromsome data, foliar SEM observations and comparisons with phenetically similar species are provided to aid in identification.

Keywords: Begonia moneta; Begonia peridoticola; Borneo; Chromosome number; Malaysia; New species; Sabah; Sect. Baryandra; Sect. Petermannia.

Figure 1

Begonia moneta C.-I Peng, Rimi & C. W. Lin. A. Habit; B. Portion of leaf adaxial surface; B’. Portion of leaf abaxial surface; C. Stipule, abaxial view, C’, C”. Stipules, side views; D, D’. Staminate flower; E, E’. Stamens, adaxial and abaxial views; F, F’. Pistillate flower; G, G’, G”. Style and stigmatic band, dorsal, side, and ventral views; H. Fruit; I. Cross sections of immature fruit. All from Peng 22344 (HAST).

Figure 2

Begonia moneta C.-I Peng, Rimi & C. W. Lin. A. Habit and habitat; B. Habit (in cultivation); C. Leaf, adaxial surface; D. Leaf, abaxial surface; E. Stipule on rhizome; F. Inflorescence; G, H. Staminate flower; I, J. Pistillate flowers; K. Young inflorescence with buds; L, L’. Cross sections of an immature fruit; M. Fruit. All from Peng 22344 (HAST).

Figure 3

Cryo SEM microphotographs of Begonia leaves. A, E: Adaxial surface; B, F: Abaxaial surface; C, G: stomata complex; D, H: Cross section. A-D: B. moneta (Peng et al. 22344, HAST); E-H: B. peridoticola (Peng 22343, HAST).

Figure 4

Somatic chromosomes at metaphase of Begonia moneta (2n = 30; Peng 22344, HAST).

Figure 5

Distribution map of Begonia moneta and B. peridoticola (Solid circle) in Sabah.

Figure 6

Begonia peridoticola Rimi, C.-I Peng & C. W. Lin. A. Habit; B. Stipule; C, C’. Lowermost bract in the inflorescence, face and side views; D’, D”. Staminate flower; E, Androecium; F, F’, F”. Anther, dorsal, ventral and side views; G, G’. Pistillate flower; H, H’, H”. Style and stigmatic band, dorsal, ventral and side views; I. Fruit; J. Cross sections of immature fruit. All from Peng 22343 (HAST).

Figure 7

Begonia peridoticola Rimi, C.-I Peng & C. W. Lin. A. Habit and habitat; B. Habit, dorsal and ventral views; C. Stipule; D. Portion of leaf, adaxial surface; E. Portion leaf, abaxial surface; F. Lowermost cyme; G. Upper cymes with staminate flowers; H. Staminate flower; I. Pistillate flower; J. Fruit, side view; K. Cross section of an immature fruit. All from Peng 22343 (HAST).