Begonia gulongshanensis Y.M.Shui & W.H.Chen, 2018

Chen, Wen-Hong, Radbouchoom, Sirilak, Nguyen, Hieu Quang, Nguyen, Hiep Tien, Nguyen 4, Khang Sinh & Shui, Yu-Min, 2018, Seven new species of Begonia (Begoniaceae) in Northern Vietnam and Southern China, PhytoKeys 94, pp. 65-85 : 70-72

Begonia gulongshanensis Y.M.Shui & W.H.Chen sp. nov. Fig. 5

Begonia sect. Coelocentrum Irmsch.

Remarks.

The new species is similar to Begonia daxinensis T. C. Ku, but different from it in its ovate leaves (vs. broadly ovate in B. daxinensis ), slightly oblique leaf base (vs. extremely oblique), glandulose-villous on peduncles, pedicels, adaxial surface of exterior tepals and fruits (vs. glabrous, sparely eglandulose-pubescent), filaments connected to a half (vs. only at base), the smaller petals of male flowers (0.7-1.2 × 0.7-0.9 cm vs. 1.2-1.9 × 1-1.6 cm), the smaller petals of the female flowers (0.9 × 1.0 vs. 1-1.5 × 1-1.2 cm).

Type.

CHINA. Guangxi Zhuang Autonomous Region, Jingxi county, Gulongshan , 23°19 ’44” N, 106°16 ’46” E, 286 m a.s.l., in the deep valley, growing on the moist surface of steep cliffs, flower pinkish, 18 February 2016, Y.M. Shui et al. B2016-048 (holotype, KUN!) .

Herb, rhizomatous.

Rhizome: 0.3-0.5 cm in diam. Stipule triangular, 0.2-0.4 × 0.6-0.8 cm, apex acute, adaxially subglabrous, abaxially hispid. Leaves all basal, alternate; petiole 5-9 cm long, glandular-hispid; blade greenish, asymmetric, ovate or ovate-lanceolate, 12-18 × 5-9 cm, base cordate, auricular, oblique or slightly oblique, apex caudate, margin serrulate; adaxially greenish, tubercular-setose, with white semi-circle in the middle and with dark red patches along the main nerves; abaxially greenish, glandular-pubescent along veinlets, sparsely villous and densely strigose on main veins; venation palmate, ca. 7 primary veins, secondary veins branching di chotomous, tertiary veins slightly reticulate, veins prominent adaxially. Inflorescence dichasial cyme, axillary, peduncle 5-9 cm, glandular-villous; bracts caducous, oblong-lanceolate, ca. 5 × 1 mm, apex acuminate, adaxially glabrous, abaxially long setulose. Staminate flower: pedicel 1.1-1.8 cm long, glandular-villous; tepals 4, pinkish to pink; outer tepals 2, widely ovate, 0.7-1.2 × 0.7-0.9 cm, apex rotund, margin entire, adaxially glabrous, abaxially glandular-villous; inner tepals 2, narrowly oblong or obovate, 0.6-1.0 × 0.2-0.25 cm, apex acute; androecium actinomorphic; stamens numerous, filaments connected to a half, ca. 1 mm long; anthers yellow, obovate, ca. 0.5 mm long, apex emarginate. Pistillate flower: pedicel ca. 1.1 cm long, glandular-villous; tepals 3, pinkish or pink; outer tepals 2, widely ovate, ca. 0.9 × 1.0 cm, apex rotund, margin entire, adaxially glabrous, abaxially glandular-villous; inner tepal 1, oblong, 5-6 × 2-3 mm, base cuneate, apex acute, margin entire; styles 3, fused at base; stigmas spiralled, papillose; ovary green, elliptic, 0.8-0.9 cm long, glandular-villous; placentation parietal, 2-segmented per carpel. Capsule nodding, 3-winged unequally; major wing ca. 3.5 mm long, lateral wings ca. 2.1 mm long.

Phenology.

Flowering in February-May, fruiting in May-June.

Etymology.

The epithet refers to the locality of the type specimens.

Habitat.

The species only grows on the moist surface of shady cliffs at the entrance to shallow caves in a deep valley.

Distribution.

The species occurs exclusively in Jingxi county of Guangxi in China.

Note.

In Begonia sect. Coelocentrum , the new species is similar to the population of B. daxinensis with a white area on the leaves, but differs mainly in its long glandular hairs ( Wu and Ku 1997; Ku et al. 2004). In the latter species, the petals are covered abaxially by brown pubescence and are much larger than those of the new species. As to the lanceolate and colourful leaves, the new species is similar to Begonia locii C.-I Peng, C. W. Lin & H. Q. Nguyen, but different in the absence of glandular hairs of flowers ( Peng et al. 2015a). Furthermore, as to the glandular pubes, the new species is also similar to B. filiformis Irmsch., but differs in the subglabrous adaxial surface and laxly pubescent abaxial surface of leaves (vs. densely pubescent adaxial and abaxial surface of leaves in the latter).

Figures

Figure 5. Begonia gulongshanensis Y. M. Shui & W. H. Chen A Habitat B View of adaxial leaf C View of abaxial leaf D Staminate flower, face view, side view and dorsal view E Pistillate flower, face view and side view F Inflorescence K Cross section of ovary in the middle part. (All photographs by Y. M. Shui).