Two new species of Camellia (Theaceae) from Vietnam
Article information
Abstract
Two new species of Camellia (Theaceae) are described from Vietnam: Camellia vuquangensis Luong, Tran & L. T. Nguyen and Camellia hatinhensis Luong, Tran & L. T. Nguyen. The new taxa were collected from Vu Quang National Park in the center of Vietnam. The new finds are morphologically dissimilar to all known Camellia species. Recent Camellia discoveries have increased the number of species recorded in Vietnam from 50 to 75, making Vietnam a center of diversity and a crucial area for more research into the diversity and distributions of Camellia.
Camellia is the largest genus of the Theaceae, with an estimated 120 to 300 species (Chang and Bartholomew, 1984; Ming and Bartholomew, 2007). According to Sealy (1958), Chang and Bartholomew (1984), Gao et al. (2005), Ming and Bartholomew (2007), about 80% of these species are found in China and others are found in Cambodia, Indonesia, Japan, Laos PDR,, Philippines, Thailand, and Vietnam.
In Vietnam, about 50 species of Camellia were recognized prior to the mid-2000’s (Ho, 1999; Ninh, 2002). However, in recent years additional species of Camellia have been discovered and described from Vietnam, increasing the total to 75 species and making Vietnam the centre of Camellia diversity (Orel and Wilson, 2010, 2012; Ninh and Dung, 2012, 2013; Orel et al., 2012, 2013, 2014a, 2014b; Luu et al., 2015; Ninh and Ninh, 2015; Dung et al., 2016; Ninh and Dung, 2016).
Vu Quang National Park with about 1,678 species of vascular plants, 94 species of mammals, 315 species of birds, 58 species of reptiles, and 31 species of amphibians, including many endemic and rare species, have been recorded, indicating that Vu Quang National Park is one of the centers of biodiversity for Vietnam (Vu Quang National Park Management Board, 2014).
During a field trip in 2016 to survey on Camellia in the Vu Quang National Park, we collected two species of Camellia. Careful examination of the morphological characters indicated and more than 300 dried specimens kept in the following herbaria were also examined: VAFS, DLU, HN, VNM as well as digitized plant specimen images available on the web of Muséum National d’Histoire Naturelle (https://science.mnhn.fr/) and Chinese Virtual Herbarium (http://www.cvh.org.cn/) that did not match any described species.
Taxonomic Treatment
1. 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).
Camellia vuquangensis Luong, Tran & L. T. Nguyen. A. Leaf, adaxial surface. B. Venation detail of leaf (abaxial surface). C. Venation of leaf (adaxial surface). D. Flower, lateral view. E. Flower, top view. F. Perules (inner surfaces shown). G. Petals (inner surfaces). H. Stamens. I. Pedicel and gynoecium (other floral parts removed) (drawn by Luong Van Dung).
Camellia vuquangensis Luong, Tran & L. T. Nguyen. A. Branches. B. Flower bud. C. Flower, lateral view. D. Flower, top view.
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.
Morphological comparison between C. vuquangensis with C. dilinhensis.
2. Camellia hatinhensis Luong, Tran & L. T. Nguyen, sp. nov. (Figs. 3, 4).—TYPE: VIETNAM. Ha Tinh province, Vu Quang district, 27 Aug 2017, Luong Van Dung, Tran Ninh, Nguyen Thi Lieu, Do Cong Thuan, Nguyen Viet Hung VN.0354 (holotype, isotype: DLU).
Camellia hatinhensis Luong, Tran & L. T. Nguyen. A. Leaf, adaxial surface. B. Venation detail of leaf (abaxial surface). C. Venation of leaf (adaxial surface). D. Flower bud. E. Flower, top view. F. Perules (inner surfaces shown). G. Petals (inner surfaces). H. Perules and gynoecium. I. Stamens. J. Capsule with persisting styles. K. Pericarpa. L. Seeds (drawn by Luong Van Dung).
Camellia hatinhensis Luong, Tran & L. T. Nguyen. A. Branches. B. Fruit. C. Flower bud. D. Flower.
Shrubs or small trees, 4–6 m tall, young branches villous becoming glabrous with age. Leaves stalked; blade thick and coriaceous, oblong, 11–15 cm long and 3–5 cm wide, glabrous above, villous below, the apex acuminate to long caudate; the base broadly cuneate or nearly rounded, the midribs sunken above and protruding below main leaf, 10 to 14 pairs of lateral veins sunken above and protruding below the main leaf, the margins serrulate or serrate; petioles 1–1.3 mm long, villous. Flowers solitary at branch apices, white, 8–9 cm in diameter, the pedicel absent. Perules 9 or 10, nearly rounded, 0.4–2.3 cm high, 0.3–2.1 cm wide, pubescent on both sides, persistent, margins ciliate. Petals 10 or 11, elliptical, nearly rounded, obovate, retire, 2.7–4.8 cm long, 2.3–4.5 cm wide, pubescent on both sides, united with outermost filaments 0.5–1.3 cm at the base. Androecium over 300 stamens, in 6 or 7 circles, 3–3.5 cm long, pubescent, outer filaments united from the base and forming a short cup, united 1.3–1.6 cm at the base. Ovary nearly rounded, 3-locular, tomentose, 0.5 cm long, 0.4 cm wide; styles 3, free to the base, 3–3.3 cm long, tomentose. Fruits globose, pubescent, 3.5–4 cm in diameter, 3-locular, with 1 or 2 seeds in each locule, columella abortive. Seeds cuneate or semiglobose, 1.6–1.9 cm high, 1.1–1.4 cm wide, glabrous.
Distribution and phenology: This species was found in the forest of Vu Quang National Park, Vu Quang district, Ha Tinh province, at the elevation over 100 m. Flowering: August to September; Fruiting: October to November.
Etymology: The specific epithet of the new species refers to the location of discovery, Ha Tinh province, Vietnam.
IUCN Red List category: The AOO for C. hatinhensis is estimated to be less than 1 km2. Despite a further search of the area around the type locality and other forests in the vicinity, only eight additional mature trees were found. The total known population of the species is fewer than 50 individuals, and it would be qualifid as CR under criterion D (IUCN, 2011).
Taxonomic remarks: Camellia hatinhensis possesses some morphological characteristics common to the species C. gauchowensis Chang, C. oleifera Abel; C. sasanqua Thunb. and C. vietnamemsis Huang ex Hu (Gao et al., 2005) belonging to Section Oleifera Hung T. Chang (Chang and Bartholomew, 1984). All these species have terminal flowers which are sessile and white; bracteoles and sepals are not differentiated, coriaceous; ovaries 3-locular; styles 3–5. Therefore the species should be classified into Sect. Oleifera Hung T. Chang. The main similarities and differences between C. hatinhensis with C. gauchowensis, C. oleifera, C. sasanqua, and C. vietnamemsis are summarized in Table 2.
Morphological comparison between C. hatinhensis with C. gauchowensis, C. oleifera, C. sasanqua, and C. vietnamemsis.
Acknowledgements
The authors would like to express their sincere thanks to Mr. Hoang Van Hoan and Mr. Le Van Toan who provided valuable information leading to the discovery of those species. We are also grateful for the support provided through the JSPS KAKENHI Grant Number JP16K07239, Japan.
Notes
Conflict of Interest
Authors declare that there is no conflict of interest.