Begonia qinzhouensis D.K.Tian & J.Y.Zhou, 2024

Tian, Dai-Ke, Zhou, Jin-Ye, Xiao, Yan, Wu, Yan-Nong, Hu, Ren-Chuan, Dong, Xun & Guan, Shi-Kai, 2024, Three new species of Begonia (sect. Platycentrum) from South China, Phytotaxa 675 (2), pp. 147-157 : 154-156

3. Begonia qinzhouensis D.K.Tian & J.Y.Zhou sp. nov. § Platycentrum (ṻfflữåDz) ( Fig. 5 )

Type:— CHINA. Guangxi Zhuang Autonomous Region, Qinzhou city (ṻfflḿ), Qinbei district (ṻ北区), Guitai town (ā台ḋ), Bazhaigou resort ( Ā Ṟṡạ区), 22°5'N, 107°15'E, alt. 108, in peak flowering period, 13 November 2023, Daike Tian, Renchuan Hu, Jinye Zhou, Xiangchun Lan TDK5560 (holotype CSH [ CSH 0204822], isotypes CSH [3]).

Diagnosis:— Begonia qinzhouensis is morphologically similar to B. edulis Léveillé (1909) but mainly differs by its deeper (1/2–2/3 vs. 1/5–1/3) lobed leaf blade, rounded to truncate (vs. acute-angled to partially overlapped) leaf base, pink to red (vs. usually white and rarely lightly pink) flowers, and later flowering (October to December vs. June to October).

Herb, perennial evergreen, rhizomatous, dioecious, 22–40 cm tall (including 1–3 erect stem internodes at anthesis). Rhizome creeping, 8–20 cm long, 8–13 mm thick, unbranched to rarely branched, grayish-green to light red, internodes very short or indistinct; erect stem with 1–3 nodes, internodes 2–22 cm long, 3–10 mm thick. Stipules caducous, only seen at upper nodes, light to deep red, long triangular, 10–20 × 4–16 mm (including apex arista 5–8 mm long), glabrous, keeled, with long apex arista. Petioles mostly light green, base greenish-brown or reddish-brown, glabrous, cylindrical, ungrooved, basal petiole 20–35 cm long, 7–8 mm thick, cauline petiole 2–15 cm long, 1.8–4 mm thick. Leaves 2–10 per plant, mostly basal, few (2–4) cauline, papery, slightly asymmetrical, ovate to nearly rounded, 6–18 × 5–18 cm; adaxially green, sparsely covered with very short bristles, bristles less than 0.5 mm long, venation palmate, primary veins 5–7, primary veins and primarily branched veins convex; abaxially grayish-green, veins distinct and convex, sparsely very short gray-white bristles along veins; blade deeply lobed nearly 1/2–2/3, 3–6 lobes, middle one 4.5–12 cm long, deeply or shallowly lobed again, non-lobed part 2.2–6 cm long; leaf base rounded to truncate or nearly truncate, margin sparsely shallow serrate and short cilia, apex long caudate. Inflorescences dichasial cyme,1–2 arising from 1–2 terminal nodes of erect stems, 9–27 cm long, unbranched or incompletely branched or only branched once; peduncle green, 8–21 cm long, 2–4 mm thick, nearly glabrous, 3–5 flowers per inflorescence. Bracts caducous-deciduous, ovate, light green to light red, abaxially grayish-green villous, without dorsal ridge and terminal awn, margin sparsely villous, basal bracts 10–15 × 8–12 mm, upper bracts 8–10 × 5–7 mm. Staminate flower: pedicel pink, glabrous, 18–22 mm long, 1.5–1.8 mm thick; flower 35–50 mm long, 30–44 mm wide; tepals 4, outer 2 glabrous, adaxially nearly white or white with light pink tint to red, veins distinct, abaxially pale pink, ovate, 18–24 × 16–22 mm, entire, adaxially depressed in central part, which is much thicker than margin part; inner 2 glabrous, white, long obovate to oblanceolate, 15–19 × 8–11 mm, entire; androecium yellow, nearly capitate, actinomorphic, 6–8 mm long, 8–9 mm wide, stamens 120–170, filaments basally connate, connate part ca. 3 mm long, 1.5 mm thick, free filaments 1–2 mm long, anthers 1–2 mm long, apex flatted or rounded. Pistillate flower: pedicel pink, glabrous, 15–20 mm long, 1.2–2 mm thick; perianth nearly circular, 26–42 mm in diameter, tepals 5, nearly glabrous; outer 2 slightly larger, pale pink, obovate, 13–22 × 11–17 mm; inner 3, gradually smaller inward, long obovate to oblanceolate, 11–19 × 8–15 mm, innermost one white; pistil 6–8 × 5–10 mm, style 2, yellow, basally connate, stigma highly spirally curled, compactly arranged, each side spiraled up to nearly 1.5 revolutions; ovary light green with reddish tint, glabrous, placentation axile, 2-loculed, placentae 2 per locule. Fruits green, glabrous, 11–14 × 9–11 mm, unequally 3-winged, glabrous, abaxial wing larger, nearly trapezoidal or rectangular, 16–20 × 13–15 mm; lateral wings distinct or nearly absent in the middle and upper part of fruits, narrowly falcate, 3–6 × 12–15 mm; fruit stalk 17–26 mm long, ca. 1.5 mm thick. Flowering Oct.–Dec. (May), fruiting Dec.–Feb..

Distribution and ecology: — The new species is currently known only in two places restricted to Qinzhou and Fangchenggang which belong to southern Guangxi of China ( Fig. 2 ). It grows usually on wet rock surfaces along the creek under forest and is rarely found on dry places.

Etymology: — The species is named after the name of Qinzhou, where the earliest specimen of this species was collected by Liang Deng & Delin Wu on 20 December 1955, Liang Deng & Delin Wu 618 (IBSC). The Chinese name is given as “ ṻfflữåDz ”.

Additional specimen examined:— China, Guangxi, Qinzhou city: Qin county (currently Qinzhou city, Qinbei district ) (ṻ县, Κ为ṻfflḿṻ北区), Nalue town (currently Guitai town ) ( Dü 乡, Κ为ā台ḋ), Gaoli village (ª ṣť), fruits, 12 December 1955, Liang Deng, Delin Wu 618 ( IBSC) ; Guitai town, Maqishan ( ḶAEƜ) (belonging to Dongli village), red flowers and dry fruits, 18 May 1960, Huimin Wu 0038 ( IBSC). All of other specimens were collected from Bazhaigou resort of Guitai town in Qinbei district (ṻ北区ā台ḋĀṞṡạ区), rock surface of wet and shady places along a creek, 22°6'N, 108°15'E, alt. 80–150 m, without flower, 4 June 2022, Jinye Zhou TDK4961 ( CSH) ; without flower, 24 July 2023, Daike Tian, Jinye Zhou, Yannong Wu TDK5354 ( CSH) ; without flower, same date and same collectors as before TDK5356 (CSH); without flower, same date and same collectors as before TDK5358 (CSH); in peak flowering period, 13 November 2023, Daike Tian, Renchuan Hu, Jinye Zhou, Xiangchun Lan TDK5561 ( CSH). Guitai town, Gaoli village, soil slope along a creek, 22°4'N, 108°13'E, alt. 80 m, with dried fruits, 2 March 2024, image by Yunbiao Liao. Fangchenggang city ( Ŀ ẅăḿ): Nasuo town (Dũḋ), Shangyue village (上ẽť), Fangcheng Golden Camellia National Naturel Reserve ( Ŀ ẅaeĸë国ẍãnḦ保ae区), with pink flowers and young fruits, 29 October 2018, image by Bo Liu .

Conservation status:— The new species is restricted to distributing in only two locations of Guangxi, which are separated only by just 40 km distance. The extent of occurrence is less than 40 km 2 (<100 km 2) and the area of occupancy is less than 8 km 2 (<10 km 2). The total number of mature plants is less than 100 (<250). Its occupancy area and the total number of mature plants are predicted to decline in the future due to climate change and specimen collection. Based on the current data as well as considering its ornamental value, this species should be treated as Critically Endangered (CR) (B1B2ab(iii,v), C2a(i)) following Guidelines for Using the IUCN Red List Categories and Criteria (IUCN Standards and Petitions Committee, 2024).

Note:— Flowering was recorded on 18 May 1960 by Huimin Wu 0038 (IBSC) collected from Maqishan of Guitai town. We regard this as an abnormal flowering time because we found that this species usually blooms between October and December.

Figures

FIGURE 2. Distribution map of the three new species: ■Begonia liangguangensis, ▲ B. shaoqingii, ★ B. qinzhouensis, ● B. qinzhouensis and B. shaoqingii.

FIGURE 5. Habitat and morphology of B. qinzhouensis D.K.Tian & J.Y.Zhou. A. Habitat; B. Habit of flowering plant; C. Inflorescence; D. Rhizome and basal portions of an aerial stem and petioles; E. Leaves showing variation in shapes and two surfaces (left two, cauline leaves adaxial surface view; right two, basal leaves (left showing adaxial surface and right showing abaxial surface)); F. Adaxial (upper) and abaxial (lower) leaf section; G. Erect stem of a mature plant; H. Bracts, abaxial surface views; I. Front (left) and back (right) views of staminate flower; J. Front (left) and oblique back (right) views of pistillate flower; K. Top (upper) and side (lower) views of androecium; L. Stigmas; M. Petiole bases and stipules; N. Abaxial (left) and oblique side (right) views of stipule; O. Side and adaxial views of fruit; P. Cross-section of ovary.