Begonia parvilimba Merr., 1925

Mazo, Kean Roe F. & Rubite, Rosario R., 2022, Two new species of Begonia (section Petermannia, Begoniaceae) from the Zamboanga Peninsula, Philippines, and a redescription of Begonia parvilimba, Phytotaxa 538 (2), pp. 163-171 : 168

3. Begonia parvilimba Merr. in PJS 26, 1925: 481. § Petermannia ( Fig. 4 )

Type:— PHILIPPINES. Mindanao, Zamboanga del Sur, Malangas (now part of Zamboanga Sibugay), October / November 1919, BS 36936 Ramos & Edaño (lectotype US, here designated) .

Herb monoecious, perennial, terrestrial, up to 20 cm tall. Stem unbranched, erect and arching, 3–5 mm in diameter, reddish maroon or green, sparsely strigose, with prominent leaf scars, internodes 1.0– 1.7 cm long. Stipules deciduous, light green to pinkish, asymmetric, oblique, ovate, 11–13 × 4–6 mm, keeled, sparsely pilose, margin ciliate, apex cuspidate. Leaves alternate; petiole terete, 2–3 ×1.5–2.0 mm, reddish-brown, strigose; lamina oblanceolate, 5–7 × 3–4 cm, base cordate, margin serrate, sinuate, undulate, on the upper third abruptly narrows into an acute apex; adaxially verrucose with gray spots, each spot with very short erect hair, olivaceous, dark green; abaxially puberulent, maroon, hirsute on midrib and veins; secondary veins 3–5 pairs. Inflorescence axillary, few-flowered, 1 or 2. Staminate flower bracteoles persistent, narrowly ovate, 5–8 × 2–3 mm, green, sparsely puberulous, margin ciliate, apex caudate; pedicel 11–13 mm long, white, puberulent; tepals 4, white suffused with pink; outer tepals suborbicular, 8–10 × 6–8 mm, adaxially glabrous, abaxially sparsely puberulent or glabrous, apex obtusely rounded; inner tepals linear, 6–7 × 1–2 mm, glabrous, apex acute; androecium actinomorphic, stamens 20–30, filaments 0.5–0.7 mm, fused at base; anthers obovoid, 1.3–1.5 mm, apex retuse. Pistillate flower bracteoles persistent, narrowly ovate, 5.5–8.0 × 2–3 mm, green, sparsely puberulous, margin ciliate, apex caudate; pedicel 1.5–3.0 mm long, white, puberulent; tepals 5, white suffused with pink, lanceolate, 6.5–7.3 × 2.0– 4.6 mm, glabrous, apex obtuse to rounded; style 3, yellow, apically bifid, 2.5–2.8 mm long, stigmas in spiral band and papillose all around; ovary trigonous-ellipsoid, pinkish-white or light green, 4–5 × 5–6 mm (wings excluded), puberulous; wings 3, equal, same color with the ovary, locules 3, placenta bilamellate. Capsule trigonous-elliptic, 6–7 × 7.5–8.0 mm (wings included); pedicel 3.5–4.0 mm long; wings 3, equal, truncate distally, rounded proximally, 5.0– 6.5 mm long, 4.0– 4.6 mm wide.

Phenology:— Observed flowering and fruiting between February to November.

Distribution and Habitat:— Begonia parvilimba is endemic to Zamboanga Peninsula, Mindanao, where it is currently known in the provinces of Zamboanga Sibugay and Zamboanga del Norte ( Fig. 1 ). The plant grows on a semi-shaded environment near waterfalls at 592 m elevation.

Notes:— The type specimen of Begonia parvilimba was collected in Malangas, Zamboanga Sibugay in 1925. Merrill (1925) noted that the B. parvilimba closely resembles B. mindanensis but significantly differs in having smaller leaves and capsules.

Additional specimen examined: Begonia parvilimba Merr. — PHILIPPINES. Mindanao, Zamboanga del Norte Province, Municipality of Leon B. Postigo, Brgy.Tinuyop, Ekam River , elevation 592 m, 8° 2’59.23”N, 122°56’24.42”E, 9 February 2021, K. R.F. Mazo 9 ( CMUH) .

Proposed Conservation Status:— Begonia parvilimba is currently known from two localities in Zamboanga Peninsula. The type locality is now part of the populated, site of coal mining municipality of Malangas. The area with the recently found record for the species at the Ekam River is an inhabited, previously kaingin area and now covered with invasive species Piper aduncum L ., in addition the nearby Ekam waterfalls is frequently visited by tourists. Here, only one population with two individuals were observed. After 16 months of fieldwork with 5 or 6 times/month site visits, no additional populations nor individuals were found. The area is not currently protected under the country’s National Integrated Protected Areas System by the Department of Environment and Natural Resources. Given the ongoing habitat change and the small number of <50 mature individuals, it is prudent to provisionally assess this species as Critically Endangered CR D.

Figures

FIGURE 1. Distribution map of known Begonia species in the Zamboanga Peninsula, Mindanao, Philippines.

FIGURE 4. Begonia parvilimba Merr. A. Habit and habitat; B. Leaf adaxial surface; C. Leaf abaxial surface; D. Stipule; E. Staminate flower, front view; F. Staminate flower, side view; G. Pistillate flower showing the ovary; H. Capsules.All from K.R.F. Mazo 9.