Begonia amamampang Mazo & Rubite, 2022

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 : 164-166

1. Begonia amamampang Mazo & Rubite , sp. nov. § Petermannia ( Fig. 2 )

Type:— PHILIPPINES. Mindanao, Zamboanga del Norte Province, Municipality of Leon B. Postigo, Brgy. Tinuyop, Sitio Binwangan, elevation 498 m, 8°3’23.67” N, 122°56’57.06” E, 28 October 2021, K. R. F. Mazo 55 (holotype PNH) .

Herb monoecious, perennial, terrestrial, up to 75 cm tall. Stem branched, erect and arching, 3–6 mm in diameter, green or reddish brown, strigose, internodes 1.0– 4.5 cm long. Stipules deciduous, green, lanceolate, 9–15 × 2.5–4.0 mm, sparsely pilose, margin ciliate, apex cuspidate. Leaves alternate; petiole terete, 3–5 × 1–4 mm, green, strigose; lamina obovate, 5–12 × 3–5 cm, base cordate, inequilateral, margin distantly serrate, apex acuminate; 2 colour forms: one is adaxially green, minutely echinate between veins, abaxially scabrid, strigose on midrib and veins; another form is adaxially surface olivaceous, dark green, minutely echinate; abaxially surface puberulent, strigose on midrib and veins, reddish maroon; secondary veins 5–7 pairs. Inflorescence axillary, few-flowered, 1(–3). Staminate flower bracteoles persistent, lanceolate, 3.2–8.0 × 1.0– 2.5 mm, green, sparsely puberulous, margin ciliate, apex caudate; pedicel 8.5– 11.0 mm long, white, minutely strigose; tepals 4, white suffused with pink; outer tepals ovate to suborbicular, 9–12 × 6.0– 7.5 mm, adaxially glabrous, abaxially sparsely puberulent, apex obtuse to rounded; inner tepals linear, 5–7 × 1.0– 2.5 mm, glabrous on both sides, apex acute or obtuse; androecium actinomorphic, stamens 18–30, filaments 0.3–0.8 mm, fused at base; anthers obovoid, 1.0– 1.4 mm, apex retuse. Pistillate flower bracteoles persistent, lanceolate, 3–11 × 1.3–2.0 mm, green, sparsely puberulous, margin ciliate, apex caudate; pedicel 2.5–5.0 mm long, white, puberulent; tepals 5, white suffused with pink; tepals lanceolate or broadly ovate to obovate, 8.0–15.0 × 6.1–8.0 mm, adaxially glabrous, abaxially sparsely puberulent to glabrous, apex obtuse to rounded; style 3, yellow, apically bifid, 4.0– 5.2 mm long, stigma in spiral band and papillose all around; ovary trigonous-ellipsoid, green or white to pinkish, 9–12 × 4.5–8.0 mm (wings excluded), short hirsute; wings 3, equal, same color with the ovary, truncate distally, 7.5–10.2 mm long, 5.4–7.1 mm wide; locules 3, placenta bilamellate. Capsule trigonous-elliptic, 11–13 × 10.8–13.0 mm (wings included); pedicel 3–5.5 mm long; wings 3, equal, truncate distally, rounded or subcordate proximally, 8.2–11.5 mm long, 4.0– 5.3 mm wide.

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

Etymology:— The epithet refers to the local name for Begonia species in the type locality.

Distribution and Habitat:— Begonia amamampang is endemic to Zamboanga del Norte, Mindanao, where it is currently known only from its type locality. The plant grows on shaded to semi-shaded areas near creeks of secondary lowland tropical evergreen forest at 300–500 m elevation.

Notes:— Begonia amamampang is similar to B. affinis Merr. in having lanceolate stipules, short petioles, and number of tepals of both pistillate and staminate flowers. However, this new species differs in having stipules deciduous (vs. persistent); petioles scabrid (vs. tomentose); leaf base obtuse and equilateral (vs. laterally cordate); adaxially surface punctuate (vs. glabrous); few-flowered axillary inflorescence (vs. terminal); and trigonous-ellipsoid capsules (vs. turbinate).

Additional specimen examined: Begonia amamampang Mazo & Rubite. PHILIPPINES. Mindanao, Zamboanga del Norte Province, Municipality of Leon B. Postigo, Brgy. Tinuyop, near sitio Tiwalos, elevation 518 m, 8°2’54.75” N, 122°55’50.12” E, 12 November 2021, K. R.F. Mazo 59 ( PNH) .

Proposed Conservation Assessment:— Begonia amamampang is known only from the Municipality of Leon B. Postigo at two close locations, with three populations each of about one or three mature individuals at one location and another with four populations each of about one or two mature individuals. After 16 months of fieldwork with 5 or 6 times/month site visits, no additional populations were found. The localities are not currently protected under the country’s National Integrated Protected Areas System by the Department of Environment and Natural Resources. Given the ongoing threats such as nearby rubber plantation, shifting cultivation, illegal logging, and the small number of <50 mature individuals it is prudent to provisionally assess this species as Critically Endangered CR D.

Figures

FIGURE 2. Begonia amamampang Mazo & Rubite. A. Habit and habitat; B. Portion of the stem showing strigose hairs; C. Leaf adaxial and abaxial surfaces showing green form; D. Leaf adaxial and abaxial surfaces showing olivaceous, dark green form; E. Staminate flower, front view; F. Staminate flower, side view; G. Pistillate flower, front view; H Pistillate flower showing the ovary; I. Cross-section of the ovary; J. Capsule.All from K.R.F. Mazo 55 except (D) from K.R.F. Mazo 59.