Begonia padawanensis

Begonia padawanensis

B. padawanensis

Quick Species Info

Species	padawanensis
Region	South East Asia
Country	Borneo, Sarawak, Malaysia
Year published	2012
Date of Origin	2013
Plant Type	Rhizomatous
Section	Reichenheimia
Chr 2n	(COUNT)

Species Information

Distribution and Ecology

Begonia padawanensis is endemic to Kuching District, Padawan, Sarawak, Borneo, near the border of Indonesia.

Habitat

It is restricted to dipterocarp forests, specifically on wet sandstone cliffs in light shade, where it attaches to mossy cracks in rocks. This species is typically found at an elevation of about 200 meters above sea level.

Description

Begonia padawanensis is a monoecious, epipetric, creeping, perennial plant. Its succulent rhizome is greenish to reddish-brown, measuring 2 to 4 cm in length and 3 to 6 mm across, with sparingly villous internodes. The stipules are persistent, triangular-lanceolate, approximately 1 cm long and 4 mm wide. They are greenish or reddish, herbaceous, entire, glabrous, and aristate-caudate at the apex, with a keeled midrib on the abaxial side.

The leaves are nearly appressed to the substrate, forming a rosette appearance. There are 3 to 10 leaves, which are alternate, simple, asymmetric, not oblique, unlobed, and obtriangular-spathulate. The basal lobes are 1.5 to 7.0 mm long, with ciliate margins that are either entire or slightly undulate. The leaves have obtuse apices, measuring 3.5 to 5.5 cm in length (including basal lobes) and 2.2 to 4.5 cm in width. The broad side of the leaves is 1.2 to 2.8 cm wide. The adaxial surface is pale green, and the texture is distinctly fleshy. The leaves are either glabrous or minutely pilose towards the base of veins and have minutely ciliate margins. The venation is basally 5 to 7 palmate, with veins pinnate along the midrib. There are 1 to 3 secondary veins on each side, which branch dichotomously or nearly so. Tertiary veins are weakly percurrent or reticulate, and minor veins are reticulate and obscure.

The petioles are terete, measuring 0.6 to 3.0 cm in length (0.6 to 1.5 cm in upper leaves, up to 3 cm in lower leaves) and 2 to 3 mm across. They are greenish to reddish and villous.

Flower Details

The inflorescence is a compound cyme, bisexual, axillary, with 1 to 4 arising directly from congested nodes on the rhizome. It is pale green to reddish and can be either glabrous or sparsely villous. The inflorescence is erect and can have up to 4 orders of branching, exceeding the leaves. The peduncles measure 4.0 to 7.5 cm in length and 0.8 to 1.2 mm in thickness. There are 2 to 6 flowers per cyme.

The bracts are greenish, herbaceous, broadly ovate to triangular-lanceolate, with sparsely dentate margins and hispid surfaces. They are rounded at the apex and measure approximately 1.5 mm long and 1 mm wide at the first node of the inflorescence. Upper bracts are 1.0 to 1.5 mm long and 0.3 to 0.7 mm wide, with a few tiny, subsessile glands.

• • Staminate flowers:** The tepals are 4, pinkish to white, with entire margins. The outer 2 tepals are obovate to broadly obovate, cuneate at the base, and obtuse or rounded at the apex. They measure 5 to 8 mm in length and 4 to 6 mm in width, with magenta or whitish abaxial surfaces. These outer tepals can be glabrous to sparsely hairy and have few tiny, subsessile glands. The inner 2 tepals are narrowly ovate to narrowly obovate, cuneate at the base, and obtuse at the apex, measuring 5.0 to 7.5 mm in length and 2 to 3 mm in width. They can be pinkish or whitish. The androecium is zygomorphic, with 13 to 15 stamens that are golf club-shaped and slightly compressed. The stamens have retuse apices, are 0.7 to 1.0 mm long, and have 2-locular anthers. The filaments are short, measuring 0.4 to 0.8 mm long and are shortly fused at the base.

• • Pistillate flowers:** The tepals are 5, rarely 4, with entire margins. They can be glabrous or sparsely hairy on the abaxial side. The tepals are oblong to widely obovate, obtuse or rounded at the apex, measuring 6.0 to 8.5 mm in length and 2 to 5 mm in width. They are adaxially white to pink and abaxially white to magenta. The ovary is trigonous-subspheric, measuring 3.5 to 4.0 mm long and 3.5 to 4.0 mm across (wings excluded). It is pale green to pinkish and 3-winged, with unequal wings that are triangular and apically obtuse. The two larger wings are 5 to 7 mm long and 3 to 4 mm tall, while the smaller wing is 2.0 to 2.5 mm tall. There are 3 locules with undivided placentae. The styles are 3, fused at the base, yellow, and approximately 2.5 mm long, with apical splits and a C-shaped form. The stigmas are arranged in a spiral band and are papillose all around.

Etymology

The specific epithet "padawanensis" refers to Padawan, where the new species was discovered.

Similar Species

Begonia padawanensis shares some similarities with B. andersonii Kiew & S. Julia, both belonging to sect. Reichenheimia. While the obtriangular-spathulate leaves of Begonia padawanensis resemble the foliage of B. blancii (sect. Baryandra, Palawan Island, the Philippines) and B. gibbsiae Irmsch. ex Sands (sect. Petermannia, Sabah, Malaysia) in some aspects, it is distinctly different and is classified under a different section. Begonia padawanensis is exclusively known from sandstone regions in southern Padawan.

Photos

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