武广山茶 Camellia vuquangensis V.D.Luong, Ninh & L.T.NguyenCamellia vuquangensis

Camellia vuquangensis Luong, Tran & L. T. Nguyen, sp. nov. (Figs. 1, 2).—TYPE: VIETNAM. Ha Tinh province, Vu Quang district, 21 Aug 2017 (fl), Luong Van Dung, Tran Ninh, Nguyen Thi Lieu, Do Cong Thuan, Thai Canh Toan, Le Van Toan, Hoang Van Hoan VN.0358 (holotype: DLU, Isotype: VAFS). First published in Korean J. Pl. Taxon. 48: 115 (2018).

The specimen was discovered by Luong Van Dung, Tran Ninh, Nguyen Thi Lieu, Do Cong Thuan, Thai Canh Toan, Le Van Toan and Hoang Van Hoan in 2016-2017 in Vu Quang district, Ha Tinh province. In 2018, the authors Nguyen Thi Lieu, Tran Ninh, Uematsu Chiyomi, Katayama Hironori, Luong Van Dung, Hoang Thanh Son,  Nguyen Danh Ky, Nguyen Viet Hung and Thai Canh Toan published in the Korean Journal of Plant Taxonomy with the scientific name Camellia vuquangensis. The Vietnamese name is Vu Quang Tea, named after Vu Quang National Park where the specimen was first discovered.

Shrub, 3–4 m tall, young branches and leaves light violet and pubescent. Leaves stalked; blade thick and coriaceous, oblong, 12–23 cm long and 4–7 cm wide, glabrous above, hirsute below, the apex acuminate to long caudate, the base auriculate with some teeth, the margins sharply serrulate, the midribs sunken above and protruding below with 17 to 22 pairs of lateral veins, sunken above and protruding below the main leaf surface; the petioles 8–10 mm long, hirsute. Flowers 1 or 2, positioned on the terminal or axillary of branches, 8 9.5 cm in diameter, shortly pedicellate. Perules 6 or 7, scale shaped to nearly rounded, 0.4–2.2 cm high, 0.4–1.6 cm wide, pubescent on both sides, ciliate margins. Petals 13 or 14, elliptic, obovate, oblanceolate, entire, light yellow, 2.5 6.0 cm long, 1.5–2.5 cm wide, emarginated, glabrous on inner surfaces, pubescent central region of outer surfaces, united with outermost filaments 0.6–1.8 cm at the base. Androecium over 290 stamens, in 6 or 7 circles, light yellow, 3.5–4.5 cm long, pubescent to 1/2 from the base, outer filaments united for 2–2.4 mm from the base and form a short cup. Ovary cylindrical, 3-locular, 5–6 mm long, pubescent; styles 3, free to the base, 1–1.3 cm long, pubescent to 1/2 from the base. Capsule not seen.

Distribution and phenology: This species was found in the forest of Vu Quang International Park, Vu Quang district, Ha Tinh province, at the elevation of 50–100 m. Blooming season: Spring, August to September.

Etymology: The specific epithet of the new species refers to the location of discovery, Vu Quang National Park, Vietnam.

IUCN Red List category: The Area of Occupancy (AOO) for C. vuquangensis is estimated to be less than 1 km2 , as extensive surveys in the wider region have not located this species elsewhere. Despite a further search of the area around the type locality, only eight additional mature trees were found. The total known population of the species is fewer than 50 individuals, and it would be qualified as Critically Endangered (CR) under criterion D (IUCN, 2011).

Taxonomic remarks: This species most closely resembles Camellia dilinhensis of sect. Obvoidae Tran et Luong (Ninh and Dung, 2013) as the leaf is elliptic oblong; flowers are yellow and are either solitary or a pair at the ends of branches; ovary 3-locular, cylindrical, pubescent; style 3, free. Thus based on morphological similarity, this species should be assigned to sect. Obvoidae Tran et Luong. The main similarities and differences between Camellia vuquangensis with Camellia dilinhensis are summarized in Table 1

 VIETNAM: Vu Quang district of Ha Tinh province

武广山茶 Camellia vuquangensis Luong, Tran & L. T. Nguyen, sp： 越南。河静省，武广地区，2017年8月21日(花期)，Luong Van Dung, Tran Ninh, Nguyen Thi Lieu, Do Cong Thuan, Thai Canh Toan, Le Van Toan, Hoang Van Hoan VN.0358(主模式：DLU，等模式：VAFS)。首次发表于《韩国植物分类学杂志》（Korean J. Pl. Taxon. 48: 115 (2018)

该标本由 Luong Van Dung、Tran Ninh、Nguyen Thi Lieu、Do Cong Thuan、Thai Canh Toan、Le Van Toan 和 Hoang Van Hoan 于 2016-2017 年在河静省武广县发现。2018 年，作者 Nguyen Thi Lieu、Tran Ninh、Uematsu Chiyomi、Katayama Hironori、Luong Van Dung、Hoang Thanh Son、Nguyen Danh Ky、Nguyen Viet Hung 和 Thai Canh Toan 在《韩国植物分类学杂志》上发表了学名为 Camellia vuquangensis 的文章。越南语名称为武广茶，以首次发现该标本的武广国家公园命名。

灌木，3-4米高，幼枝和叶浅紫色，具短柔毛。叶有柄；叶片厚而具革质，长圆形，长12-23厘米，宽4-7厘米，上面无毛，下面具长硬毛，先端渐尖到长尾状，基部耳形，有一些齿，边缘有锐细锯齿，中脉上面凹陷，下面突出，有17到22对侧脉，上面凹陷，下面突出于主叶面；叶柄长8-10毫米，具长硬毛。花 1 或 2 朵，位于枝条的顶端或腋下，直径 8 9.5 厘米，有短花梗。花被 6 或 7，鳞片状至近圆形，高 0.4-2.2 厘米，宽 0.4-1.6 厘米，两面被短柔毛，边缘具缘毛。花瓣 13 或 14，椭圆形、倒卵形、倒披针形，全缘，淡黄色，长 2.5-6.0 厘米，宽 1.5-2.5 厘米，微缺，内表面无毛，外表面中央区域有短柔毛，基部与最外层花丝合生 0.6-1.8 厘米。雌雄蕊超过 290 枚，6 或 7 圈，淡黄色，长 3.5-4.5 厘米，自基部起被短柔毛至 1/2，外花丝自基部起 2-2.4 毫米合生，形成短杯状。子房圆筒状，3室，长5-6毫米，被短柔毛；花柱3，离生至基部，长1-1.3厘米，被短柔毛至基部的1/2。蒴果未见。

分布和物候： 该物种发现于河静省武广县武广国际公园的森林中，海拔 50-100 米： 春季，八月至九月。

词源： 新物种的特称指的是发现地点：越南武广国家公园。

世界自然保护联盟红色名录类别： Vuquangensis 的栖息地面积（AOO）估计不到 1 平方公里，因为在更广泛的地区进行的广泛调查并未在其他地方发现该物种。尽管对模式产地周围地区进行了进一步搜索，但只发现了另外 8 棵成熟的树木。该物种的已知种群总数少于 50 个，根据标准 D（世界自然保护联盟，2011 年），该物种将被列为极度濒危物种（CR）。

分类学备注： 该物种与Camellia dilinhensis同组sect. Obvoidae Tran et Luong (Ninh and Dung, 2013)，叶片为椭圆形长圆形；花黄色，单生或一对生于枝端；子房 3 室，圆柱形，被短柔毛；花柱 3，离生。因此，基于形态上的相似性，本种应归入sect. Tran et Luong。表 1 总结了武冈山茶（Camellia vuquangensis）与山茶（Camellia dilinhensis）的主要异同点。

河静省武广县武广国际公园