Begonia chingipengii R. Rubite. A 2014, sp. nov.
Creators: name: Rubite, Rosario Rivera
name: Callado, John Rey C.
name: Kono, Yoshiko
name: Yang, Hsun-An
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Cucurbitales
Begoniaceae
Begonia
Begonia chingipengii

description: Begonia chingipengii R. Rubite, sp. nov. (Figures 1, 2)
Type: — PHILIPPINES. Luzon Island. Nueva Ecija: Gabaldon, Barangay Malinao, Maplud River, elev. ca. 415 m, on grassy, rocky slope, exposed to semi exposed, 25 October 2011, Ching-I Peng, Chien-I Huang, Rosario R. Rubite & John Rey C. Callado 23368 (holotype PNH, isotype CAS, E, HAST, HUH, MO).
Monoecious perennial, rhizomatous herbs. Rhizome green, glabrous, prostrate, 18–20 mm in diameter, internodes 5–10 mm. Stipules pink to maroon, glabrous, ovate, 1.8–3 × 1.8–3.2 cm, asymmetric, prominently keeled and with brown curved hairs (1–2 mm), apex acute. Leaves alternate; petiole 22–35 cm long, 8–12 mm across, erect, terete, succulent, light brown to maroon, brown tomentose (2–3 mm), trichomes more dense at the junction with lamina; blade ovate, 16–19(–32) × 13–17 cm, adaxial surface glabrous and glossy, generally dark green with prominent light green midrib and veins (width of variegation on midrib 4–6 mm, on primary veins 3–4 mm, secondary veins 2–3 mm), abaxial surface maroon between the green veins, brown tomentose, base obliquely cordate, lobes rounded, sinus when young overlapping (1 cm), when mature open at about 8 mm, apex elongate acuminate, tip of primary veins slightly acute (about 1–2 mm), margin brown ciliate (2–3 mm), primary veins 10 or 11. Inflorescences 32–52 cm long, axillary, arising directly from the rhizome, dichotomously branched 5 times; peduncle pink, 26–45 cm long, 8–12 mm across, erect, densely brown- to maroon-hairy, hairs 2–3 mm; bracts caducous, orbicular, boat-shaped, pink, 1.2–1.4 × 1.8–2.2 cm, glabrous; pedicels pink, in staminate flowers 2.5–3.2 cm long, erect to ascending, in carpellate flowers 1.5–4.2 cm long, ascending to horizontal. Male flowers: bracteoles orbicular, boat-shaped, white, 0.8–1.2 × 1.4–1.8 cm, glabrous; tepals 4, dark pink or whitish, glabrous, outer pair orbicular, 1.4–2.2 × 1.2–1.6 cm, inner pair obovate, 0.8–1.2 × 0.4–0.8 cm; androecium actinomorphic, with 30–40 stamens, filaments 1–2 mm long, free; anthers yellow, rounded, ca. 0.5 mm long. Female flowers: tepals 4, dark pink or whitish, glabrous, outer pair orbicular 1.2–1.8 × 1.6–2.2 cm; inner pair obovate, folded, not retuse, 0.7–1.5 × 0.4–0.6 cm; ovary pink (pale green in cultivation), 8–18 × 6–12 mm, wings unequal, three-locular, placentae axile, bifid; styles three, 7–9 mm long, stigma yellow, twice coiled. Capsule glabrous, nodding, ca. 1.2–2 × 1–2.2 cm, unequally 3-winged, abaxial wing 1–2.1 × 0.8–1.6 cm, rounded; lateral wings 1.2–2 × 0.5–1 cm.
Chromosome cytology:— Somatic chromosomes at mitotic metaphase of Begonia chingipengii were determined to be 2 n = 28 (Figure 3). The 28 chromosomes gradually varied from ca. 1.0 to 2.2 µm in length. Several longer chromosomes were identifiable as metacentric and/or submetacentric, however, centromere positions of shorter chromosomes were uncertain. Satellites were not observed.
Recently, members of Begonia sect. Diploclinium (Lindley ex R. Wight 1852: 9) A. de Candolle (1859: 129) from the Philippine were transferred to sect. Baryandra, based on the analysis of morphological features and molecular data (Rubite 2012; Rubite et al. 2013). Among about 50 species in sect. Baryandra, six that were studied showed chromosome numbers ranging from 2 n = 26 to 2 n = 56, namely, 2 n = 26 in B. fenicis Merrill (1908: 421) (Oginuma & Peng 2002); 2 n = 28 in B. gueritziana Gibbs (1914: 82) (Hughes et al. 2011); 2 n = 30 in B. blancii M. Hughes & C.-I Peng (2011: 204) and B. suborbiculata Merrill (1912: 398) (Hughes et al. 2011); 2 n = 36+2f in B. parva Merrill (1912: 402) (Legro & Doorenbos 1969); 2 n = 44 in B. rhombicarpa A. De Candolle (1859: 129) (Doorenbos et al. 1998 as B. nigritarum); 2 n = 56 in B. fenicis (Kokubugata & Madulid 2000). To our knowledge, however, 2 n = 28 and 2 n = 30 are the predominant chromosome numbers in Begonia sect. Baryandra in the Philippines (our unpublished data), with which that of B. chingipengii agrees.
Leaf anatomy:— Both surfaces have sparse glandular trichomes (Figure 4A, B); stomata on the abaxial surface helicocytic, 1–4 clustered (Figure 4B), slightly elevated; cross section ca. 0.46 mm thick, epidermis biseriate, with a layer of thick hypodermis (160–220µm) under upper epidermis and a thinner layer of hypodermis (ca. 100µm) under lower epidermis (Figure 4C).
Ecology:— Disturbed broadleaf forest; on rocky slope above stream.
Etymology:— The plant is named in honor of Dr. Ching-I Peng, the leader of the expedition, collaborator, mentor and supporter of R. R. Rubite in the studies of Philippine begonias.
Additional specimen examined (paratype):— PHILIPPINES. Luzon Island. Nueva Ecija: Gabaldon, Brgy. Malinao, elev.ca. 250 m, small waterfall NE of Stone & Resort, on moist rock or soil, semishaded, rare, 26 October 2011, Ching-I Peng, Chien-I Huang, Rosario R. Rubite & John Rey C. Callado 23397 (HAST).
Notes:— Many Philippine begonias when cultivated tend to be stunted in growth and would lose the variegated leaves, becoming all green but not B. chingipengii. It continues to produce large beautiful variegated leaves.
description: Published as part of Rubite, Rosario Rivera, Callado, John Rey C., Kono, Yoshiko & Yang, Hsun-An, 2014, Begonia chingipengii (sect. Baryandra, Begoniaceae), a new species from Luzon Island, Philippines, pp. 175-182 in Phytotaxa 164 (3) on pages 177-179, DOI: 10.11646/phytotaxa.164.3.2, http://zenodo.org/record/5132722