Begonia gabaldonensis Rubite, C.I Peng & C.W. Lin, 2018

Rubite, Rosario R., Peng, Ching-I, Chung, Kuo-Fang, Lin, Che-Wei, Evangelista, Luisito T., Tandang, Danilo N., Callado, John Rey C. & Hughes, Mark, 2018, Three new species of Begonia (section Baryandra, Begoniaceae) from Luzon Island, the Philippines, Phytotaxa 347 (3), pp. 201-212 : 204-207

2. Begonia gabaldonensis Rubite, C.I Peng & C.W. Lin , sp. nov. ( Figs. 3 & 4 ).

Type:— PHILIPPINES. Luzon, Nueva Ecija, Gabaldon, Barangay Malinao, Maplud River, on soil slope that is shaded and moist, elevation ca. 525 m, 15°29’43”N, 121°20’54”E, 25 October 2011, Peng 23356, with Chien-I Huang, Rosario R. Rubite, John Rey C. Callado (holotype PNH, isotype HAST).

Monoecious rhizomatous herb. Rhizome long creeping, to 15 cm or longer, 4.5 − 6 mm thick, densely appressed hirsute, hairs magenta to pink, turning white to pale brown with age; internodes 0.3 − 1 cm long. Stipules persistent, magenta, triangular, 6–10 mm long, 5–8 mm wide, herbaceous, strongly keeled, few fleshy red hairs fused into at the base of the keel, keel with a acute-angled triangular on topped, hirsute; densely hirsute adaxially, margin entire, apex aristate, arista ca. 3 mm long. Leaves alternate, petiole terete, reddish, 8 − 17 cm long, 2.5 − 4.5 mm thick, densely hirsute, hairs magenta to pink, turning white to pale brown with age, sometimes with few fleshy red hairs at base of petiole; leaf blade asymmetric, oblique, widely ovate, 7.3 − 11 cm long, 5.4–10 cm wide, broad side 3.8–7 cm wide, basal lobes cordate, 2–3.5 cm long, midrib 4.1–7.2 cm long, apex acuminate, margin denticulate and lined with puberulous or hirsute, hairs white to magenta; leaf thick chartaceous, adaxially green to blackish brown green or maroon, with sparsely small silvery grey to pale pink dots between veins; adaxially sparsely puberulous; abaxially pale green, hirsute on all veins; venation basally ca. 9–palmate, midrib distinct, ca. 2 secondary veins on each side, other primary veins branching dichotomously or nearly so, tertiary veins reticulate. Inflorescence axillary, bisexual, cymosely branching panicle 15–26 cm long, peduncle 11–17 cm long, dichasial cymes arising directly from rhizome, branched 4–8 times, erect or ascending, pale green to reddish, appressed hirsute; protandrous. Bracts pinkish, hyaline, deciduous, those at basal node of inflorescence ovate to widely ovate, boat-shaped, ca. 10 mm long, 7 mm wide, apex obtuse to rounded or retuse, margin entire or with hirsute at lower half; bracts at summit of inflorescence similar but smaller. Staminate flower: pedicel 0.5–0.7 cm long, glabrous; tepals 4, white, sometimes with pinkish toward to basal, glabrous; outer 2 widely ovate to suborbicular, 0.8–1.1 cm long, 0.7–1 cm wide; inner 2 obovate or oblanceolate, 0.7–1.2 cm long, 0.4– 0.7 cm wide, apex rounded to retuse; androecium actinomorphic, ca. 0.3 cm across; stamens yellow, 29–34; filaments short fused at base; anthers obovate, ca. 0.7 mm long, 2-locular, apex rounded to truncate, subequal at filaments. Pistillate flower: pedicel 0.4–0.6 cm long, glabrous; tepals 4, white or pinkish toward to basal, outer 2 elliptic to ovate or obovate, glabrous, 0.5–1.3 cm long, 0.5–1.1 cm wide, inner 2 oblanceolate to widely obovate, 0.4–0.7 cm long, 0.3–0.8 cm wide, apex rounted to truncate; ovary creamy to pinkish, body trigonous-ellipsoid, 3–5 mm long, 1.7–2.5 mm thick (wings excluded), glabrous; 3-winged, subequal, wings 4–6.5 mm long, crescent-shaped, cordate at proximal, truncate or slightly cordate to cuneate at distal, (1–) 2.5–5.5 mm wide, margin entire; ovary 3-locular, placenta bilamellate, ovules reddish; styles 3, shortly fused at base, yellow, 2.5–3 mm long, stigma spirally twisted. Capsule pendent, pedicel 0.5–0.7 cm long, tepals deciduous; body trigonous-ellipsoid, 6–7 mm long, 2.5–4 mm thick (wings excluded), greenish or reddish when fresh; wings subequal, ca. 7–9 mm long, 2–6 mm wide.

Etymology:— Named for the type locality, Gabaldon, where the new species was collected.

Distribution and habitat:— Begonia gabaldonensis is endemic to Gabaldon area of Nueva Ecija Province in eastern Luzon. The type locality consists of riparian forest on steep slopes and mossy sandstone boulders in deeply shaded, wet areas near streams.

Notes:— Begonia gabaldonensis is similar to B. luzonensis in having hairy rhizomes, hirsute petioles and widely ovate laminae, 4-tepalled staminate and pistillate flowers, and a truncate, distal wing. However, the new species differs in having shorter internodes (0.3 − 1 cm vs. 2 − 5 cm) in its rhizomes; a glabrous (vs. sparsely puberulous) upper lamina surface with light green to silvery grey stripes (vs. sparsely small-dotted) between the veins; an inflorescence with appressed hirsute hairs (vs. glabrous); and the reddish (vs. white) ovules. This species, according to the phylogenetic placement in Hughes et al. (2015), is part of a very recently diverged (Pleistocene) clade species including Begonia biliranensis Merrill (1915: 46) , B. luzonensis and Begonia nigritarum Steudel (1821: 194) .

Figures

FIGURE 3. Begonia gabaldonensis Rubite, C.I Peng & C.W. Lin. A. Habit; B. Stipule; C. Bracts at lowermost parts of inflorescence; D, D’. Staminate flower, face and side views; E, E’, E’’. Stamen, dorsal, side and ventral views; F, F’. Pistillate flower, face and side views; G, G’, G’’. Style and stigmatic band, dorsal, side and ventral views; H. Capsule; I. Cross section of an immature capsule. All from Peng 23356 (HAST).

FIGURE 4. Begonia gabaldonensis Rubite, C.I Peng & C.W. Lin. A, B. Habit and habitat; C. Rhizome, showing stipules and petioles; D. Stipules; E. Leaf, upper surface; F. Inflorescence with staminate and pistillate flowers; G. Bracts on an immature inflorescence; H. Staminate flower, face views; I. Pistillate, face and side views; J. Capsule; K. Cross section of an immature capsule. All from Peng 23356 (HAST).