Vaccinium bangliangense Y.S. Huang & Y.H. Tong, 2022

Huang, Yu-Song, Nong, Shi-Yue, Li, Xing-Kang, Xie, Gao & Tong, Yi-Hua, 2022, Vaccinium bangliangense, a new species of Ericaceae from limestone areas in Guangxi, China, PhytoKeys 194, pp. 23-31 : 23

Vaccinium bangliangense Y.S. Huang & Y.H. Tong sp. nov.

Figs 1 , 2A-C , 3A, B , 4

Diagnosis.

Vaccinium bangliangense Y.S. Huang & Y.H. Tong belongs to V. section Conchophyllum Sleumer (1941) and is morphologically similar to V. pseudotonkinense Sleumer and V. sciaphilum C.Y. Wu in having small and dense obovate leaf blades with a retuse apex, hairy young branches and calyx and campanulate corollas, but can be distinguished from the former by basal glands on leaf blade margin at 0.3-0.8 mm (vs. 2.6-4 mm, Fig. 3C ) distance from petiole, inflorescence with very short peduncle or up to 5 mm long (vs. very short, Fig. 2E ), calyx lobes with ciliolate margin and a gland at apex (vs. with ciliate and glandular margin and without a gland at apex, Fig. 3D ) and, from the latter, by inflorescence with very short peduncle or up to 5 mm long (vs. very short, Fig. 2G ), longer (5-7 mm vs. ca. 3 mm) and glabrous (vs. densely pubescent, Fig. 2G ) pedicel, glabrous or sparsely villous (vs. densely hispid) calyx tube, glabrous or sparsely pubescent (vs. densely hispid, Fig. 3F ) calyx lobes with a gland at apex (vs. without a gland at apex, Fig. 2I ) and densely villous (vs. glabrous) filaments. A detailed morphological comparison amongst the three species is summarised in Table 1 .

Type.

China. Guangxi Zhuang Autonomous Region: Baise City, Jingxi City , Renzhuang Town , Bangliang protection station, campsite of Huitun , 850 m a.s.l., 2 June 2021, S.Y. Nong & P. Yang ZYA00199 (holotype: IBSC!; isotypes: IBK!, IBSC!) .

Description.

Small evergreen shrubs, 10-20 cm tall, usually epilithic, sometimes epiphytic on tree trunks. Stem ascending, with long creeping rhizomes. Roots with bead-like swellings 1-3 cm in diam. Young branches brownish-red, grey when older, densely white villous, glabrescent. Leaves dense; petiole 1-2 mm long, red, adaxially sparsely pubescent, glabrescent, abaxially glabrous; blades obovate or broadly obovate, 1-1.7 × 0.6-1.2 cm, leathery, adaxially near margin sparsely villous when young, glabrescent, abaxially sparsely brown glandular hispidulous, base cuneate, basal gland 1 per side, at 0.3-0.8 mm distance from petiole, margin entire, revolute, apex obtuse, slightly retuse; mid-vein impressed adaxially, raised abaxially; lateral veins 2-4 pairs, flat and inconspicuous or impressed adaxially, raised abaxially. Inflorescence shortly racemose, 2-flowered or solitary, axillary or borne on leafless old stems; peduncle very short or 3-5 mm long, base with several bracts, glabrous or sparsely white villous on distal part; bracts ovate, 0.5-1 mm long, ca. 0.5 mm wide, margin ciliolate, apex glandular; pedicel 5-7 mm long, glabrous, thickening towards the apex, articulate with the calyx tube; bracteoles 2, adnate to 1-3 mm above the pedicle base, triangular-ovate, ca. 1 × 0.5 mm, margin ciliolate, apex glandular; calyx tube green or purple green, obconical, ca. 1.5 × 2 mm, glabrous or sparsely villous; calyx limb divided nearly to the base; lobes 5, triangular-ovate, ca. 2 × 1.5 mm, both surfaces glabrous or sparsely pubescent abaxially, margin ciliolate, apex glandular; corolla yellowish-green or tinged reddish, broadly campanulate, ca. 9 × 5 mm, both surfaces glabrous, 5-lobed; lobes triangular-ovate, apical part reflexed, apex acute, pubescent abaxially, glabrous adaxially; stamens 10, 5.5-6 mm long; filaments white, tinged reddish in reddish flowers, flat, incurved, ca. 2 mm long, densely villous; anthers yellow, 4-5 mm long, thecae ca. 1.5 mm long, tubules 3-3.5 mm long, with 2 spurs at the base abaxially, spurs ca. 1.3 mm long, interlocked (that is: the spurs on antesepalous stamens extending laterally outside of antepetalous anthers and strongly overlapping with spurs of next antesepalous stamens, those on antepetalous anthers strongly hooked outward below spurs of antesepalous stamens); disc yellowish, annular, glabrous; style greenish, tinged reddish in reddish flowers, cylindrical, ca. 6.5 mm long, glabrous, stigma truncate; ovary pseudo-10-locular, each locule with several ovules. Berry globose, ca. 8 mm in diam., glabrous, greenish when young, white when mature, fruiting calyx persistent, narrowly triangular-ovate and slightly inflexed; seeds reniform, ventrally compressed, 1.5-2 mm long, testa brownish, cells elongated, with thickened anticlinal walls.

Phenology.

Vaccinium bangliangense was observed flowering from May to June and fruiting from August to October (and up to January of the following year in indoor cultivated plants).

Etymology.

The specific epithet is derived from the type locality, Bangliang Gibbon National Nature Reserve of Guangxi, China. The Chinese name is given as " 邦亮越橘 (pinyin: bāng liàng yuè jú)”.

Distribution and habitat.

Thus far, Vaccinium bangliangense was found only in Bangliang Gibbon National Nature Reserve of Guangxi, China. It usually grows on rocks of limestone hillside or peak at an elevation from 850-900 m, sometimes on the trunks of Pistacia weinmanniifolia J. Poisson ex Franchet ( Anacardiaceae ). The slope direction is to the south and the slope gradient is ca. 30°. The tree layer is up to 8 m tall with a canopy cover of 70% and the shrub and herb layer covers are 85% and 20%, respectively. The associated species include Quercus phillyreoides A. Gray ( Fagaceae ), Sinosideroxylon pedunculatum (Hemsl.) H. Chuang var. pubifolium H. Chuang ( Sapotaceae ), Ardisia pseudocrispa Pit. ( Primulaceae ), Schefflera pesavis R. Vig. ( Araliaceae ), Tetradium calcicola (Chun ex C.C. Huang) T.G. Hartley ( Rutaceae ), Sageretia camelliifolia Y.L. Chen & P. K. Chou ( Rhamnaceae ), Paraboea swinhoei (Hance) B.L. Burtt ( Gesneriaceae ), Bonia amplexicaulis (L.C. Chia et al.) N.H. Xia ( Poaceae ), Bulbophyllum andersonii (Hook. f.) J.J. Smith ( Orchidaceae ) etc.

Conservation status.

Vaccinium bangliangense has only been found in Bangliang Gibbon National Nature Reserve of Guangxi, China. As a new species, more subpopulations of V. bangliangense could probably be found in similar habitats of surrounding limestone areas in the future. However, wild surveys have been conducted for more than ten years in the area where the new species was found. Only two subpopulations were found in the protected region with a total of fifteen individuals and seven of these are mature. Based on the current data, its population size is very small, and the area of occupancy (AOO) is restricted. According to Guidelines for Using the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2022), the conservation status of V. bangliangense should be assessed as Critically Endangered (CR), based on criteria D of ( IUCN 2012).

Additional specimens examined

(paratypes). China. Guangxi Zhuang Autonomous Region: Baise City, Jingxi City , Renzhuang Town , Bang Liang protection station, 900 m a.s.l., 2 June 2021, S.Y. Nong & P. Yang NSY2021060201 (IBK); Guilin City, cultivated in Botany Garden of Guilin , collected from the same locality as above, 16 January 2022, Y.S. Huang 2022011601 (IBK) .

Figures

Figure 1. Vaccinium bangliangense A habitat B habit C young branch, showing the leaves with a sparsely villous margin D fruiting branch E flowering branch with tinged reddish flowers F inflorescence borne on leafless old stem with yellowish-green flowers G flower (lateral view) H flower (vertical view) I flower bud J, K flowers with opened corolla L flower with corolla and stamens removed M bracteole N transection of ovary O calyx tube and disc P androecium and adaxial (left), lateral (middle) and abaxial (right) view of a stamen Q infructescence R seeds. Scale bars: 5 mm (G-I, P, Q); 1 mm (M-O, R).

Figure 2. A-C Vaccinium bangliangense A flowering branch with tinged reddish flowers B flowering branch with yellowish-green flowers C fruiting branch D-F V. pseudotonkinense D flowering branch with opened flower E flowering branch with unopened flower F fruiting branch G-I V. sciaphilum G flowering branch H leafy branch I fruiting branch. All by Yi-Hua Tong, except G by Xin-Xin Zhu.

Figure 3. A, B Vaccinium bangliangense A basal gland B calyx, arrows showing apical glands C, D V. pseudotonkinense C basal gland D calyx, showing lobes with a ciliate and glandular margin E, F V. sciaphilum E basal gland F calyx. Scale bars: 2 mm.

Figure 4. Vaccinium bangliangense A SEM micrograph of seed B elongated cells of testa. Scale bars: 100 μm.