Begonia caramoanensis Rubite, Irabagon, Palacio, Y.P.Ang, R.Bustam., 2020

Begonia caramoanensis Rubite, Irabagon, Palacio, Y.P.Ang, R.Bustam. View in CoL sp. nov.

sect. Baryandra

Type:— PHILIPPINES. Luzon Island: Province of Camarines Sur, Municipality of Caramoan, Barangay Caputatan, moist rocks under trees and shrubs, elevation ca. 30 m, 13°45’44”N, 123°52’6”E, 2 November, 2018, R. R. Rubite 988 ( holotype PNH). Fig. 2–3 View FIGURE 2 View FIGURE 3 .

Monoecious perennial rhizomatous herbs. Rhizom e dark green to maroon to brown, 4 to 16 cm long, 10–16 mm thick, subglabrous, internodes 4–8 mm long. Stipules ovate, green to pink to brown, apex aristate, 7–19 × 5–14 mm, with prominent pink to red keel and with tuft of pink hairs ( 6–10 mm long) on the abaxial side. Leaves alternate; petiole, green to maroon to brown, terete, 12–26 cm long and 4–8 mm thick, tomentose (0.5–2.0 mm green to brown hairs); blade mostly obliquely rounded some obliquely wide ovate, 8–11 × 8–12 cm, adaxial lamina dark green to maroon, glabrous, abaxial lamina light green to maroon with prominently raised veins, pilose with light green to maroon hispid ( 0.5–1 mm long), denser on the veins, margin shallowly undulate almost entire, ciliate; base cordate, lobes rounded, apex obliquely rounded to slightly acute, venation palmate, primary veins 9–10. Inflorescence axillary, arising directly from the rhizome, dichotomously branched ca. five times; peduncle light green to maroon to brown 10–25 cm long and 2–5 mm thick, erect, with white to green to brown glandular hairs ( 0.5–2 mm) varying from sparse to dense. Bracts boat-shaped, pink to maroon 4–5 × 5–6 mm, with white to green to brown glandular hairs ( 0.5–1 mm), bracteoles pink to maroon, densely covered with glandular hairs, boat-shaped, 2.5–4 × 4–5 mm in staminate flower and ovate, 2–2.5 × 3–4 mm in pistillate flower. Staminate flower: pedicel light green to maroon, erect to ascending, 3–18 mm with pinkish to green glandular hairs ( 0.5–1 mm) varying from sparse to dense; corolla 15–20 × 12–18 mm; tepals 2+2, white, glabrous, outer pair orbicular to oblong 7–9 × 7–8 mm, inner pair oblanceolate 5–8 × 2–3 mm, adaxial side of both outer and inner tepals white, while abaxial side pinkish, androecium actinomorphic, stamens 25–30, filaments 1 mm long, shortly united at the base; anthers yellow, oblong, 1 mm long. Pistillate flower: pedicel green to pink, ascending at the beginning then later recurving downwards, 9–10 mm with pinkish to green glandular hairs ( 0.5–1 mm), varying from sparse to dense; corolla 14–16 × 13–15 mm; tepals 2+3, outer pair orbicular 6–7 × 6–7 mm; pinkish abaxial and white adaxial, 3 inner tepals white, asymmetrical, 6–9 × 2–5 mm; ovary pinkish green, oblong 4–7 × 3–4 mm (wings excluded), wings 3, unequal, 6–10 mm long, lateral wings, narrowly crescent-shaped, 3–6 mm wide, abaxial wing much protruded, crescent-shaped, acute or rounded at proximal, truncate at distal, 8–14 mm wide, ovary and wings with pinkish glandular hairs ( 0.5–1 mm), tri-locular, placentae axile, bifid; styles three, 2–4 mm long, stigma yellow, spirally twisted and papillose all around. Capsule pendent, glabrous, recurved such that the largest wing is facing downwards, 6–12 × 14–22 mm, obliquely rounded to sub-rhomboid in outline.

Diagnostic characters:— The long glandular hairs on the bracts, peduncle, pedicels and ovary of B. caramoanensis is a rare character in the members of section Baryandra . It is shared with two other Philippine species, B. droseroides Rubite et al. (2018: 201) and B. palemlemensis Calaramo et al. (2019: 36) . B. caramoanensis is distinguished from B. droseroides by its suborbicular (vs. oblique, widely ovate) and larger leaves with 8–11 × 8–12 cm (vs. 5.4−8.2 × 4.4–7 cm); smaller staminate flowers with outer tepals 7–9 × 7–8 mm (vs. 11–16 × 10–17 mm), inner tepals 5–8 × 2–3 mm (vs. 9–17 × 3–6 mm) and 25–30 stamens (vs. 34–43). B. caramoanensis is differentiated from B. palemlemensis by its subglabrous rhizome (vs. densely pilose); suborbicular (vs. widely ovate) and smaller leaves with 8–11 × 8–12 cm (vs. 9−14 × 7–9 cm); smaller staminate flowers with outer tepals 7–9 × 7–8 mm (vs. 8–10 × 8–10 mm), inner tepals 5–8 × 2–3 mm (vs. 9–12 × 3–6 mm) and 25–30 stamens (vs. 47–60).

Etymology:— The species epithet is named after the type locality.

Distribution and Habitat:— The plants grow abundantly on moist rocks under trees and shrubs over limestone forests together with other herbaceous plants like Impatiens sp. and Elatostema sp.

Conservation Status:— About 500 to 700 individuals, was observed in each of the four barangays of Caramoan, thus according to to the IUCN red list categories and criteria ( IUCN 2012), B. caramoanensis is hereby proposed to be placed under Least Concern (LC) category.

Begonia caramoanensis is the latest addition to the growing number of Philippine Begonia sect. Baryandra , which now includes 73 species worldwide (Hughes et al. 2015–). The province of Camarines Sur is now the home of two endemic begonias, B. caramoanensis and B. madulidii . The researchers recommend the consideration of these species as icons of conservation at the Caramoan National Park.