Begonia benitotanii Rubite, Tandang & C.W. Lin, 2021

Rubite, Rosario Rivera, Brillantes, Rochelle Yongque, Tandang, Danilo N., Moran, Cecilia B., Rule, Mark Gregory Q. & Lin, Chei-Wei, 2021, Begonia benitotanii (section Petermannia, Begoniaceae) a new species endemic to the Philippine island of Bucas Grande, Phytotaxa 513 (3), pp. 257-264 : 259-262

Begonia benitotanii Rubite, Tandang & C.W. Lin , sp. nov. ( Figs. 2 & 3 )

Type:— PHILIPPINES. Bucas Grande Island, Province of Surigao del Norte, Municipality of Socorro , Barangay Sudlon , elevation 102 m, 9°38’50.8”N, 125°55’11.9”E, 19 December 2018, R . Rubite 1003 (holotype PNH) .

Monoecious, perennial, glabrous herb. Stem erect, 2–4 m tall, 7–12 mm in diameter, dark green some becoming brown, internodes 7–12 cm long, nodes slightly swollen. Stipules deciduous, green, oblong, 25–30 × 4–10 mm, slightly keeled, glabrous, margin entire, apex mucronate. Petioles green, terete, 4–7 cm long, ca. 2.5 mm in diameter, glabrous. Leaves glabrous, obovately oblong, asymmetric, base obliquely cordate, apex acuminate, margin irregularly serrate and undulate, 8–21 × 6–12 cm; adaxially uniformly emerald green, sometimes with sparse, large, white spots between veins, veins sulcate; abaxially pale green to pinkish, veins emergent; venation palmate-pinnate, primary veins 7 or 8. Inflorescence terminal opposite a leaf, separate inflorescence between male and female; female inflorescence with short peduncle (7–10 mm) flowers basal, borne in pairs; male inflorescence with longer peduncle (2–3 cm) flowers apical on short cymes branching 3–4 times; protogynous. Bracts deciduous, light green, basal pair lanceolate, 9–11 × 2–3 mm, margin entire. Staminate flower: pedicel 5–7 mm long; tepals 2, pink, orbicular, 4–5 × 4–5 mm, margin entire, apex rounded; androecium actinomorphic; stamens 15–20, golden yellow; filaments 0.5–2 mm, slightly fused at base; anthers very widely obovate, apex truncate to round, ca. 1.5 mm. Pistillate flower: pedicel 4–6 cm long; tepals 5, pink, obovate to elliptic, 11–15 × 4–11 mm, margin entire, apex acute; ovary light green to pink, elliptic, 10–14 × 9–11 mm (wings excluded), 3-locular, placentation axile; 3-winged surrounding and extending beyond the ovary, wings pink, equal; styles 3, golden yellow, ca. 3 mm long, apically 2-cleft; stigmas in a spiral band. Capsule trigonouselliptic, 30–38 × 20–36 cm including wings; pedicel 5–7 cm long; wings 3, equal, truncate to rounded distally, cuneate proximally, 30–38 mm long, 10–18 mm wide.

Etymology:— This species is named in honor of Professor Benito C. Tan, a distinguished Filipino muscologist, who inspired a lot of students from different parts of the world to study plants.

Distribution and habitat:— Begonia benitotanii is endemic to Surigao del Norte Province, Caraga Region, Mindanao, where it is currently known only from its type locality. The plants grow on soil slopes with coconut and banana plants.

Notes:— B. benitotanii is similar to B. balangcodiae in having upright stems, adaxial leaf green, sometimes with sparse, large, white spots, two-tepaled staminate flowers and five-tepaled pistillate flowers, and capsule with 3 equal wings. However, the new species differs in having longer stems, petioles, pistillate flower pedicels, larger lamina, stipules, ovaries and capsules; stipules oblong (vs. ovate-triangular); leaf shape obovately oblong (vs. lanceolate) apex acuminate (vs. acute), adaxial leaf green along the veins, veins sulcate (vs. reddish along veins, veins flat), abaxial leaf pale green to pinkish, emergent veins (vs. crimson, flat veins); pink, orbicular staminate tepals, 4–5 × 4–5 mm (vs. white, sometimes greenish at apex, ovate, 12–18 × 10–12 mm); pink wings surrounding and extending beyond the ovary (vs. reddish, does not surround and extend beyond the ovary).

Conservation status: —In 2011, there were two populations observed, each of about 300 individuals in a 100 m area. During our recent fieldwork, one population was found totally decimated while the other was reduced to just about 100 individuals. The site is being converted into coconut, banana and rice plantations. The area is not currently protected under the country’s National Integrated Protected Areas System by the Department of Environment and Natural Resources. These observations of B. benitotanii satisfy the IUCN Red List CR (Critically Endangered) Criteria B1ab(ii,iii,v)+2ab(i,ii,iii,v) ( IUCN, 2019), i.e. the species has an EOO <100 km 2 and is known from only a single location with inferred and observed declines in area of occupancy, quality of habitat and number of mature individuals, and an AOO <10 km 2 at the single location with a reduction in area of occurrence, occupancy, extent and quality of habitat, and number of mature individuals. Therefore, B. benitotanii is hereby proposed to be placed under Critically Endangered (CR) category.

Figures

FIGURE 2. Begonia benitotanii Rubite, Tandang & C.W.Lin. A. Habit; B. Stipule; C-C''. Bracts; D, D'. Staminate flower, face and side views; E, E'. Stamens, dorsal and ventral views; F, F'. Pistillate flower, face and side views; G, G'. Style and stigmatic band, ventral and dorsal views; H. Capsule; I. Cross section of an immature capsule. All from R. Rubite 1003.

FIGURE 3. Begonia benitotanii Rubite, Tandang & C.W.Lin. A, B. Habit and habitats; C. Stipule; D. Inflorescence; E. Staminate flower; F. Pistillate flower, face and side views; G. Immature capsules; H. Cross section of an immature capsule. All from R. Rubite 1003.