Begonia polyclada, Peng, Ching-I, Rubite, Rosario Rivera & Lin, Che-Wei, 2017

Peng, Ching-I, Rubite, Rosario Rivera & Lin, Che-Wei, 2017, Begonia polyclada (sect. Petermannia, Begoniaceae), a gracile new species from Luzon, Philippines, Phytotaxa 296 (1), pp. 93-97 : 93-94

1. Begonia polyclada C.-I Peng, C. W. Lin & R. Rubite, sp. nov. ( Figures 1 , 2 ) ṪÜḦfi⁂

Sect. Petermannia

Type:–– PHILIPPINES. Luzon, Aurora, Baler Municipality, Baler , to 600 m elev. Specimens pressed from plants originated from the wild and grown in the experimental greenhouse, 25 Oct 2012, Ching-I Peng 23553 (holotype PNH; isotype HAST) .

Plant monoecious, perennial. Stem much branched, erect, to 35 cm tall, 1–3.5 mm thick, olive to crimson, sparsely to densely appressed tomentose and sparsely glandular hairy, glabrescent, internodes 0.2–1 cm long on upper branches, to 4 cm on lower stem, nodes swollen. Stipules pale green, hyaline, narrowly triangular, 3.5–5.5 mm long, 0.5–1 mm wide, glabrous, slightly keeled, margin entire, apex cuspidate, cusp ca. 0.5 mm long; persistent. Petioles terete, 0.8–2.5 mm long, ca. 0.5 mm thick, pale green to red, tomentose, glabrescent later. Leaves numerous, subsymmetric, held horizontally; lamina ovate to ovate-lanceolate, asymmetric, base unequal, rounded to subcordate, margin dentate with shapely pointed vein endings, 7–16 mm long (basal lobes included), 3.5–8 mm wide, broad side 1.9–4.5 mm wide, adaxially emerald green, glabrous, slightly succulent, abaxially pale green, appressed puberulous on veins; venation pinnate, midrib 3.1–7 mm long, with ca. 2 major lateral veins on each side, other primary veins branching dichotomously; all veins on abaxial side slightly prominent. Bracts at basal node of inflorescence pale green, narrowly triangular to ovate-triangular, 1.5–2 mm long, 0.3–0.5 mm wide, glabrous, margin entire, turning brown and persistent. Inflorescence unisexual, peduncle white to pale green, puberulous, staminate inflorescence a simple cyme, axillary on upper branches or terminal, peduncle 1–3.5 mm long, with up to 3 flowers, ascending; pistillate flower usually 1 on a subsessile peduncle, axillary on upper branches; protogynous. Staminate flower: pedicel 7–10 mm long, glabrous or sparsely puberulous, tepals 2, white, widely ovate to orbicular, 8–11 mm long, 7–10 mm wide, margin entire, apex acute to rounded; androecium nearly actinomorphic, stamens ca. 15, filaments subequal, slightly fused at base; anthers very widely obovate, apex retuse, ca. 0.8 mm long, equal to or longer than filaments. Pistillate flower: pedicel 4–5 mm long, glabrous to sparsely puberulous; tepals 5, white to pinkish, margin entire, narrowly elliptic to ovate, 7–13 mm long, 3–5 mm wide, base cuneate, apex acute to attenuate; ovary trigonous-ellipsoid, 7–10 mm long, 3–4.5 mm across (wings excluded), white to pinkish, 3-locular, placentation axile; 3-winged, wings subequal, rounded-triangular, ca. 10 mm long, 3.5–5.5 mm wide; styles 3, golden yellow, bifid, ca. 3 mm long, apically split and C-shaped; stigmas in a spiral band and papillose all around. Capsule recurved horizontally, pedicel ca. 5 mm long, capsule ca. 1 cm long, up to 1.5 cm wide (wings included), glabrous, wings 3, subequal, subrectangular, truncate distally, cuneate or obtuse proximally, ca. 1 cm long, 4.5–6.5 mm wide.

Additional specimen examined:–– PHILIPPINES. Luzon, Aurora, Baler Municipality, Baler, to 600 m elev., 5 July 2010, Pi-Fong Lu 20597 ( TAIF).

Distribution and ecology:–– Endemic to Baler, Aurora Province, Luzon, Philippines; on deeply shaded cliffs or soil slopes, elevation up to 600 m.

Etymology: –– The epithet polyclada refers to the multi-branched stem of the new species.

Notes:–– Begonia polyclada has the smallest leaves of any Philippines Begonia . It is apparently allied to a small group of climbing species of Begonia from Philippines that can be recognized by the axillary inflorescences, 2-tepalled staminate flowers, and numerous sub-symmetric, relatively small-sized leaves, e.g. B. aequata A. Gray (1854: 658), B. binuangensis Merr. (1918: 40), B. edanoi Merr. (1918: 314), B. gracilipes Merr. (1912: 405), B. lagunensis Elmer (1912: 406), B. sarmentosa L.B.Sm. & Wassh. (1983: 443) and B. wenzelii Merr. (1915: 277). The new species however can be distinguished from the allied species by its erect habit, tomentose stem and the uniformly diminutive leaves. A comparison of the distinguishing features of B. polyclada with allied species is shown in Table 1.

Figures

FIGURE 1. Begonia polyclada C.-I Peng, C. W. Lin & R. Rubite. A. Habit; B. branch; C. Stipule; D. Bract; E, E’. Staminate flower, face and side views; F, F'. Stamen, drosal and side views; G, G'. Pistillate flower, face and side views; H, H', H''. Style, dorsal, side and ventral views; I. Capsule. All from Peng 23553 (HAST).

FIGURE 2. Begonia polyclada C.-I Peng, C. W. Lin & R. Rubite. A. Habit; B. Upper branches with pistillate flower; C. Staminate flowers, face view; D. Pistillate flower, side view; E. Immature capsule.All from Peng 23553 (HAST).