Begonia lanuzaensis Blasco, Rubite, Cortes & Alejandro, 2021

Blasco, Freddie A., Rubite, Rosario R., Cortes, Junelito C. & Alejandro, Grecebio Jonathan D., 2021, Begonia lanuzaensis (sect. Petermannia, Begoniaceae) a new species from Surigao del Sur, Mindanao Island, Philippines, Phytotaxa 523 (3), pp. 203-207 : 204-206

publication ID	https://doi.org/ 10.11646/phytotaxa.523.3.1
DOI	https://doi.org/10.5281/zenodo.5596422
persistent identifier	https://treatment.plazi.org/id/2A18960E-DF28-FFB3-7FF2-2CF06EFA69E9
treatment provided by	Plazi
scientific name	Begonia lanuzaensis Blasco, Rubite, Cortes & Alejandro
status	sp. nov.

Treatment

Begonia lanuzaensis Blasco, Rubite, Cortes & Alejandro View in CoL , sp. nov. ( Figs. 1 View FIGURE 1 & 2 View FIGURE 2 )

Sect. Petermannia

Type:— PHILIPPINES. Mindanao Island. Surigao del Sur, Lanuza, Mt. Nabuywang , Poblacion , elev. ca. 100 m, on shady, moist rocky slopes along sides of small streams, 27 May 2013, Freddie A . Blasco 13-910 (holotype PNH, isotype USTH) .

Diagnosis:— Begonia lanuzaensis is similar to B. mindanaensis Warb. in its habit with arching stems, oblanceolate leaves with short petioles, and four–tepalled staminate flowers. However, the new species differs in having larger leaves (18–20 × 7–9 cm, not 7–10 × 2–4 cm) with tiny pink bristles on the margin (vs. without bristles), glabrous stipules (vs. pubescent), glabrous stems (vs scabrid), and female flowers with 4 tepals (vs. 5).

It superficially resembles B. agusanensis Merr. in having erect stems and leaves with short petioles, but differs in leaf shape (base obliquely acute, not obliquely cordate) and male flowers solitary in the axils (not in many flowered cymes on a long peduncle).

Description:— Monoecious perennial herb, stands ca. 45 cm. tall. Stem red to brown, glabrous, erect and arching, 5–8 mm diameter, internodes 12–28 mm. Stipules persistent, triangular, green, 9‒12 × 5‒7 mm, apex acuminate, margin entire, glabrous. Leaves alternate, petioles terete, succulent, green, 4–6 mm long and 2–3 mm in diameter with tiny bristles; lamina green, oblanceolate, 18–20 × 7–9 cm, apex long acuminate becoming broad at the middle and narrowing towards the base, adaxial surface shows evenly spaced bristles, glossy dark green with a prominent light green midrib and veins, abaxial surface light green and smooth, base obliquely acute, margin broadly serrate with slightly pink tiny bristles and a pink stripe along its side, hairs on the veins absent. Inflorescences axillary, flowers solitary. Male flowers: bracteoles linear, 1–2 mm × 0.5 mm; perianth segments 2+2, pink, outer pair orbicular, 6–7 × 4–5 mm inner pair linear, 3–4 mm × 1–1.5 mm, pedicel 5–7 mm × 0.5–1 mm; stamens 20–30, yellow; filaments free 0.5 mm long; anthers obovate, apex rounded, dehiscing along 2 slits that runs along the length, ca. 1 mm long. Female flowers: bracteoles narrowly triangular, 2–3 mm × 0.5–1 mm; perianth segments 3+1, pink, outer tepals ovate, 7–8 × 5 mm, inner tepal lanceolate, 6–7 × 3–4 mm; ovary 12 × 7 mm (wings excluded), 3-locular, placentation axillary, placentae bifid bearing ovules on both surfaces of branches; styles 3, deciduous, 2.5–3 mm long, stigma yellow, spiral.

Fruit: pedicels 4 mm; fruit glabrous, pink, upright capsules, 1.8–2 × 1.6–1.7 cm, triangular in outline, apex truncate, the base obtuse, unequally 3-winged, abaxial wings 1–1.2 × 0.8–0.9 cm, lateral wings 1–1.2 cm × 0.5–0.6 cm.

Phenology:— Flowering is from April to June.

Etymology:— The specific epithet “ lanuzaensis ” is derived from the type locality.

Distribution and ecology:— Endemic to the Province of Surigao del Sur, Mindanao, Philippines. It grows on shady, moist rocky slopes along sides of small streams.

Proposed IUCN category:— Vulnerable (VU) under criterion D2. At the moment it is only known from the type collection site but it is likely that other populations exist in neighboring forests. The species is quite uncommon at the type locality and indigenous tribes populate the area. Some neighboring land mass is also being developed for agricultural purposes. Hence we consider this species to belong to the ‘prone to the effects of human activities or stochastic events within a very short time period in an uncertain future’.