Vaccinium guangdongense W.P.Fang & Z.H.Pan (1981: 112)

Tong, Yi-Hua, Zeng, Si-Jin, Ni, Jing-Bo & Xia, Nian-He, 2018, Supplementary description of floral morphology of Vaccinium guangdongense W. P. Fang & Z. H. Pan (Ericaceae), Phytotaxa 360 (1), pp. 81-84 : 82-83

Vaccinium guangdongense W.P.Fang & Z.H.Pan (1981: 112) .

Type:— CHINA. Guangdong: Yangchun, Hewei Mountain , 6 June 1957, Zhanjiang Botany Expedition 4247 (holotype IBSC-0002581!; isotypes IBSC-0420192!, SYS-00109541!) .

Inflorescences pseudoterminal or axillary, racemose, 2.5–5 cm, puberulent, 6–12-flowered, slightly zigzag; bracts caducous, leaflike, ovate to elliptic, 4–4.5 × 2–2.5 cm, glabrous, margin ciliate; bracteoles 2, ovate, 0.5–1 mm long, densely puberulent, margin ciliate. Pedicel 2.5–3.5 mm long, densely puberulent. Hypanthium ca. 1 mm long, densely pubescent; calyx lobes triangular, ca. 1 mm long, densely pubescent, margin ciliate. Corolla white, rarely reddish, tubular, 5-angled, 7–8 mm long, densely pubescent adaxially, puberulous abaxially; lobes slightly reflexed, triangular, ca. 1 mm long. Filaments 3–3.5 mm, densely pilose; anthers ca. 2.5 mm, with spurs ca. 0.3 mm long, tubules ca. 1.5 times as long as thecae. Disk densely pubescent. Style robust, tapered toward to the apex, glabrous; stigma punctate; ovary 10-pseudoloculed. Fl. May; fr. June-July.

Distribution:— Endemic to Guangdong Province (Taishan, Yangchun), South China.

Ecology and habitat:— The population of Vaccinium guangdongense in Nanfeng Mountain grows in evergreen broadleaf forests at elevations of 300– 700 m. The dominant species of the forests is Polyspora axillaris (W.Roxburgh ex Ker Gawler 1818: pl.349) R.Sweet ex G. Don (1831: 574; Theaceae ) and Baeckea frutescens Linnaeus (1753: 358 ; Myrtaceae ), with some other associated species, like Dunnia sinensis Tutcher (1905: 70 ; Rubiaceae ), and unidentified species of Syzygium ( Myrtaceae ), Ilex ( Aquifoliaceae ), etc.

Conservation status:— Only several individuals of Vaccinium guangdongense were found at Nanfeng Mountain. Another specimen of this species (Z. X. Li et al. 0554, IBSC) was collected from Xiang Ling, which is also located in Chixi Town and about 6 km away from Nanfeng Moutain. We also have conducted two field trips to the type locality, i.e., Hewei Mountain, which is about 150 km away from Nanfeng Mountain, but no individuals of this species were found. Because no population assessment of this species in the field has been made, it is best classified as ‘Data Deficient’ (DD) ( IUCN 2012).

Similar species and notes:— There are three sheets of the gathering Zhanjiang Botany Expedition 4247, two of which are deposited in IBSC and one in SYS. The sheet IBSC-0002581 bears both the handwritten and typewritten identification labels, and Fang & Pan (1981) also provided the black-white photo of this sheet in the protologue. The sheet IBSC-0420192 was misidentified as V. bracteatum and kept in another folder separated from IBSC-0002581. Therefore we conclude that the sheet IBSC0002581 is the only element examined by Fang & Pan (1981), and thus this sheet should be regarded as holotype.

According to Sleumer’s infrageneric classification system of Vaccinium, Fang assigned V. guangdongense to V. sect. Eococcus Sleumer (1941: 420), because it has caducous bracts, which is the most important character to separate V. sect. Eococcus from V. sect. Bracteata Nakai (1927: 234) ( Sleumer 1941, Fang 1991). However, this character is very unstable according to our field observations. The bracts of V. guangdongense sometimes are persistent, while even the ones of the type of V. sect. Bracteata , i.e., V. bracteatum , sometimes are caducous. Recent preliminary phylogenetic results also revealed that neither of the two sections is monophyletic ( Tong 2014), so the delimitation of these two sections may be arbitrary, and there is still much work to solve the sectional assignment problem of V. guangdongense .

Vaccinium guangdongense is further distinct from V. bracteatum in having ovate to elliptic bracts, anthers with spurs 0.3 mm long and tubules ca. 1.5 times as long as thecae, while V. bracteatum has lanceolate bracts, anthers without spurs and tubules 2–2.5 times as long as thecae. Thus, with the supplemented description of floral characters, it is much easier to key out the two species.

Additional specimens examined:— CHINA. Guangdong: Taishan County, Chixi Town, Xiang Ling , 15 May 1981, Z. X. Li et al. 0554 ( IBSC) ; Taishan County, Chixi Town, Nanfeng Moutain , 25 June 2016, Y. H. Tong, J. B. Ni & S. J. Zeng TYH-879 ( IBSC) ; ibid. 25 June 2016, Y. H. Tong, J. B. Ni & S. J. Zeng TYH-880 ( IBSC) ; ibid. 14 May 2017, Y. Y. Liu TYH-1019 ( IBSC) .