Begonia medinae Bucay, Tandang & K.F.Chung, 2025

Bucay, Mark Angelo C., Tandang, Danilo N., Chen, Hong-Wun, Tsai, Li-Wei, Rubite, Rosario R. & Chung, Kuo-Fang, 2025, Morphological and molecular analyses revealed two new species of Begonia sect. Baryandra in the Eastern Mindanao Biodiversity Corridor, Philippines, Phytotaxa 698 (4), pp. 245-256 : 250-251

Begonia medinae Bucay, Tandang & K.F.Chung , sp. nov. § Baryandra ( Figs. 4 & 5 )

Type:— PHILIPPINES. Mindanao. Davao Oriental province, in rocky walls inside forest formation along cliffside. ca. 400 masl, 14 September 2023, MACBucay 1247 (holotype: PNH!, isotype: HAST!)

Diagnosis:— Begonia medinae resembles B. elmeri , another species originally described in Agusan del Norte, also part of the Eastern Mindanao Biodiversity Corridor. Both species are the only peltate species described from the island to date. However, B. medinae is significantly different from B. elmeri in terms of vestition. A distinctive character of B. medinae is the dense white pilose hairs on the lamina (vs. glabrous to sometimes sparsely ciliate in B. elmeri ). Begonia medinae also has the same hairs in the petioles (vs. fulvus hairs), and peduncle (vs. glabrous). Other differences are summarized in Table 4.

Monoecious, lithophytic, perennial, rhizomatous herb with creeping, stout rhizome. Rhizome brown to dark red, glabrous, lenticelate, 14–24 cm × 6–11 cm, internode 7–10 mm. Stipules persistent, cream, ovate, 13–22 × 5–9 mm, herbaceous, glabrescent, keeled, margin entire, apex acute to acuminate. Leaves alternate; petioles terete, fleshy, dark red, 11.4–19.3 cm × 3–6 mm, with pilose white hairs; lamina asymmetric, ovate to elliptic, 6.3–12.3 cm from point of attachment to apex, 8.9–18.3 cm from basal lobes to tip, 8–12 cm wide, margins entire, with white dense pilose hairs, apex obtuse to rounded, peltate, adaxial surface dark green to dark red, with dense pilose to strigose white hairs, abaxial surface dark red, with pilose to strigose white hairs, venation 7–8 palmate, lighter coloration along the veins, dichotomously branching, slightly raised in both surfaces. Inflorescence axillary, bisexual, 27.4–38.9 cm long, dichasial cyme, dichotomously branching 7–10 times; peduncle erect, reddish at base, pale green to white at tip, 24.2–31.9 cm long, sparse pilose white hairs; bracts caducous, white to transluscent, keeled, lowest pair 2–3 × 2–3 mm, glabrous, apex acuminate, margin entire. Staminate flower: pedicel 18–22 mm long, light brown to light pink, glabrous, tepals 4; outer tepals 2, orbicular, pink, 12–16 × 11–16 mm, glabrous, apex round, margins sinuate; inner tepals 2, oblanceolate, pink, 9–12 × 5–7 mm, glabrous, apex cordate, margin entire; androecium zygomorphic, 2–3 mm across; stamens 28–32, filament 0.5–0.6 mm long, united at base; anthers obovoid, apex rounded. Pistillate flowers: pedicel 10–11 mm long, glabrous; tepals 4; outer tepals 2, obovate, light pink, 10–11 × 10–11 mm, apex rounded, margins entire, glabrous; inner tepals 2, oblanceolate, 5–7 × 5–6 mm, pink, apex rounded, margins entire, glabrous; styles 3, light green, 4 mm long, united at base; stigmas, spiral and densely setose-papillose, yellow; ovary: locular part ellipsoidal, apex rounded, base cordate, white, 6 × 4 mm, 3-locular, placentae axial bifid, glabrous, with three subequal cup-shaped wings, abaxial wing slightly bigger than both lateral wing, base rounded to truncate, apex rounded to truncate, light pink to white; Capsule: trigonous-ellipsoid, with subequal wings, abaxial wing elongatedtriangular, apex truncated, base acute, lateral wings, same shape but smaller than abaxial wing, base rounded to obtuse, 12–28 × 45– 11 mm.

Distribution and Ecology: —The species is observed further inland, thriving on shaded rocky areas near a cliff leading to a river. The species is found only on the type locality in Caraga, Davao Oriental ( Fig. 3 ).

Etymology: —The specific epithet “ medinae ” is to acknowledge the Filipino entomologist Dr. Milton Medina who originally observed this Begonia during their biodiversity studies in the area. This also commemorates their efforts in their conservation studies of the Philippine biodiversity, particularly the ecosystems in Davao Oriental province and the whole of Mindanao Island.

Phenology: —The species is observed to be flowering during the months of August to September.

Proposed Conservation Status:— The species is observed to have a very limited population. Residents who stayed in the locality for decades have not documented the species outside the locality and observed declining individuals of the plants (A2a). Less than 100 individuals were found, only about half are mature individuals (C2ai). The type locality is foreseen to be in danger of future degradation as trail clearing for trekking may devoid the plants with shade, and the plants’ appearance might subject it to possible exploitation (A2d). The species is observed to have a restricted Area of Occupancy (AOO) on its type locality only covering less than 100 square metres. Other rocky areas along the forests where assessed but no other populations of the plant were observed (B2aii, iv, v). We then recommend the species to be listed as Critically Endangered A2ad, B2aii,iv,v, C2ai.

Figures

FIGURE 3. General location of the type locality of B. medinae and B. dorisiae in the eastern portion of Mindanao Island, Philippines. Map by MACB.

FIGURE 4. Begonia medinae Bucay, Tandang & K.F.Chung. A. Habit; B. Rhizome; C. Stipules; D. Petioles; E. Adaxial leaf surface; F. Abaxial leaf surface; G. Bracts; H. Leaf margin; I. Staminate flower; J. Pistillate flower; K. Ovary; L. Capsule.

FIGURE 5. Begonia medinae Bucay, Tandang & K.F.Chung. A-B. Pistillate flower; C. Ovary; D. Staminate flower; E. Capsule crosssection; F. Bracts; G. Stipules; H. Habit.