Begonia aristata Blasco, Alejandro & Rubite, 2025

Blasco, Freddie A., Alejandro, Grecebio Jonathan D. & Rubite, Rosario R., 2025, Begonia aristata (Section Petermannia, Begoniaceae), a new species from Surigao del Sur, Philippines, Phytotaxa 697 (3), pp. 282-287 : 283-286

Begonia aristata Blasco, Alejandro & Rubite sp. nov. sect. Petermannia ( Figs. 1 , 2 & 3 )

Type: PHILIPPINES: Mindanao, Surigao del Sur, Matho, Cortes, Surigao del Sur elevation ca. 0– 10 m. asl. on coconut farm near a coast, May 10, 2022, Freddie A. Blasco 22-007 (holo PNH).

Diagnosis:— Begonia aristata resembles Begonia benitotanii Rubite, Tandang & C.W.Lin in having erect and branching stems, ovate-lanceolate leaves with a serrated margin, 2-tepaled staminate flowers, and 5-tepaled pistillate flowers with 3 equal wings on the ovary but differs in being 45 cm tall (vs. 200–400 cm), having smaller triangular stipules, 11–14 × 5–7 mm (vs. oblong, 25–30 × 4–10 mm) with aristate apex (vs. mucronate), smaller leaf blade 13–15 × 5–6 cm (vs. 8–21 × 6–12), adaxially brownish scabrid (vs. emerald green with white patches), base obtuse (vs. obliquely cordate), female flowers in pairs are of equal height with the branching staminate flowers (vs. female flowers basal to staminate flowers) and oblong capsule 15–16 × 19–20 mm (vs. elliptic 30–38 × 20–36 mm).

Monoecious perennial herb, standing ca. 45 cm. tall, stem erect and branching, sometimes curved, reddish to greenish, glabrous, 6–7 mm in diameter, internodes 5–8 cm long, nodes slightly swollen. Stipules triangular, persistent, solitary, sometimes triplets, the other 2 guardians are caducous, prominently keeled when young, keel cease to be visible when mature; greenish when young, pinkish to reddish when mature, 11–14 × 5–7 mm, adaxial and abaxial surface glabrous, base truncate to cordate, margin entire, apex aristate, arista 0.05–1 mm. Petioles terete, succulent, greenish to reddish, 6–7 × 3–4 mm in diameter, glabrous. Leaves alternate, ovate-lanceolate, lamina green, 13–15 cm × 5–6 cm, adaxial surface scabrid, dark green, sometimes with brown to gray patches between veins, abaxial surface brownish, scabrid, base obtuse, margin serrate with slightly red tiny bristles along its side, venation palmate, primary veins 5–6, veins glabrous, apex long acuminate. Inflorescence axillary, protogynous, peduncle ca. 5 cm then separates between male and female; female inflorescence with peduncle ca. 2 cm, female flowers borne in pairs (not basal to staminate); male inflorescence with peduncle ca. 2 cm, short cymes branching 3–5 times. Bracts semipersistent at the base of the inflorescence, light green with transparent pinkish along its margin, basal pairs, lanceolate, 13–15 × 4–5 mm, margin entire, apex aristate, arista 2–3 mm. Staminate flowers pedicel 5–6 mm, tepals 2, light pink, broadly ovate to orbicular 5–6 × 5–6 mm, margin entire, apex obtuse to orbicular, androecium actinomorphic 3 × 3 mm in diameter, stamens 15–20, yellow; filaments 0.3–0.5 mm, slightly fused at the base to dehiscing 2 slits that runs along the length, anthers obovate ca. 0.5 mm, apex retuse. Pistillate flowers pedicel 5–6 mm, tepals 5, pink to white, turns white as it goes maturity, uniformly obovate, 10–12 × 5–6 mm, margin entire, apex roundly obtuse; ovary greenish with pink wings, oblong 15–17 × 19–20 (wings included), locular part 13–15 × 5–6 mm (wings excluded), 3- locular, placentation axile, wings 3, pink, sub-equal surrounding and extending beyond the locules 15–16 × 10–11 mm, angular, apex sharply obtuse, styles 3, yellow, ca. 2 mm long, apically two-cleft, stigmas in a curled, spirally extended band and conspicuously feathery. Capsule nodding, drying pale brown, glabrous, trigonous oblong, 15–16 × 19–20 mm (wings included), pedicel 5–6 mm, wings 3, sub-equal, apex truncate to roundly obtuse, base cordate.

Phenology:— Observed flowering and fruiting in September and October (in full bloom).

Etymology:— The epithet refers to the prominent aristate apex of the bracts and stipules.

Distribution and Ecology:— Endemic to the province of Surigao del Sur, Caraga Region, Eastern Mindanao, Philippines. It thrives with banana and coconut plants on rocky slopes near the coast of Matho, Cortes, Surigao del Sur, elev. 0–10 m asl.

Proposed IUCN category:— We only observed one population of this new species, consisting of perhaps 20 individuals. The precise population size and distributional range of B. aristata has not yet been discovered. Information about the species will become available through more investigations in the remaining forest regions close to the type site and its surrounding municipalities. We propose that this new species be classified as Data Deficient [DD] ( IUCN, 2022).

Notes:— Begonia aristata also resembles Begonia longistipula Merr. in having glabrous, erect, and branching stems, long acuminate leaf apex, lanceolate bracts, 2-tepaled staminate flowers, 5-tepaled pistillate flowers, ovary with 3 equal wings and nodding glabrous capsules, but differs in having stipules with aristate apex (vs. acuminate), ovate leaves with an obtuse base (vs. oblanceolate, base acute or obtuse), serrated margin (vs. denticulate), semi-persistent bracts with aristate apex (vs. deciduous with acuminate apex), female flowers in pairs at equal height with the staminate flowers (vs. solitary female flower basal to staminate flowers), and capsule with cordate base (vs. acute).

Figures

FIGURE 1. Begonia aristata Blasco, Alejandro & Rubite. A & B. Habit and habitat.All from Freddie A. Blasco 22-007.

FIGURE 2. Begonia aristata Blasco, Alejandro & Rubite. A. Stem, B. Young stipules, C. Mature stipule. D. Inflorescence. E. Bracts, F. Staminate Flower, G. Pistillate flower, H. Cross section of the ovary, I. Capsule.All from Freddie A. Blasco 22-007.

FIGURE 3. Begonia aristata Blasco, Alejandro & Rubite. A., B., C., & D. Different stages of the inflorescence. All from Freddie A. Blasco 22-007.