{'fraction_non_alphanumeric': 0.05540300436116944, 'fraction_numerical': 0.04038119851397189, 'mean_word_length': 4.749303621169917, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 3, 'lorem ipsum': 0, 'www.': 1, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
CAMELLIA THUANANA (CAMELLIA SECT. CHRYSANTHA) – A NEW SPECIES FROM THE CENTRAL HIGHLANDS, VIETNAM

Camellia thuanana, a new species of the genus Camellia L. (Theaceae) is described and illustrated from the Central Highlands, Vietnam. Morphological features of this species are small flowers and pedicellate; leaves stalked, anastomosing venation, blades oblong-elliptic to elliptic, sparsely hirsute along the midrib below; pedicel very short; bracteoles 2–3, triangular; sepals 4–(5) in opposite pairs; corolla light greenish-yellow color; petals 7–8, glabrous; androecium 190–200 stamens, light yellow, in 3–4 circles; gynoecium 3, ovary ovoid and pubescent; styles 3, free to the base, and glabrous. C. thuanana resembles C. thuongiana in some morphological characteristics. C. thuanana is classified into sect. Chrysantha by styles completely free, flowers yellow, ovaries 3–5 locular, and partially connate. The IUCN Redlist Category of C. thuanana was assessed as Critically Endangered (CR).


INTRODUCTION
Camellia is the largest genus of the Theaceae; the number of species is estimated to be from 120 to 300 (Chang & Bartholomew, 1984;Ming & Bartholomew, 2007;Orel & Curry, 2015). The distribution of Camellia is centered in southern and eastern Asia with major distributions in China (about 80%) and Southeast Asia (about 20%) comprising Vietnam, Laos, Thailand, Indonesia, and Singapore (Orel & Curry, 2015;Sealy, 1958;Tran, 2002).
In 2020, Le et al. updated a checklist that included 126 species and five varieties of five genera of Theaceae in Vietnam based on the APG 4 classification system, of which 95 species and two varieties belong to Camellia. Tran et al. (2019) reported 52 golden Camellia species worldwide. Recently, five new Camellia species were published in two years (2020-2021): C. bidoupensis, C. flosculora, C. ngheanensis, C. proensis, and C. puhoatensis Le et al., 2021;Nguyen et al., 2020;Quach et al., 2021;Truong et al., 2020). Three new Camellia species as C. bidoupensis, C. flosculora, and C. proensis, were found in Lam Dong Province (Le et al., 2021;Quach et al., 2021;Truong et al., 2020). The number of known Camellia species increased to 100 by early 2021 Le et al., 2020;Le et al., 2021;Nguyen et al., 2020;Quach et al., 2021;Truong et al., 2020). During a field trip in November 2012 to survey camellias in Lam Dong Province, several interesting yellow flower camellias were found, and a new specimen was collected at Bao Loc at 700 to 850 m elevation. Only two individuals of this new species were found in a 1 km 2 area. An examination of herbarium specimens shows that this species is new to science.

MATERIALS AND METHODS
The description is based on measurements of mature living trees. New specimens were compared to those of closely related species in the following herbaria: DLU, HN, P, K, and NSW. Available digital images were accessed from botanical websites: https://science.mnhn.fr, http://www.cvh.org.cn, https://avh.ala.org.au, and https://apps.kew.org. The general terminology is the same as that used in Chang (1981), Chang and Bartholomew (1984), Gao et al. (2005), Ming and Bartholomew (2007), and Sealy (1958). The new specimens were compared to specimens of the closely related species, C. thuongiana, DL.160107 (holotype, isotype, DLU) and DL.160108 (paratype, DLU).

Phenology
Flowers during the rainy season; fruit not seen.

Etymology
The specific epithet of this species honors Mr. Do Cong Thuan, a member of the survey staff who has notably contributed to the collection, cultivation, and conservation of Vietnam's camellias.

Habitat and Ecology
Camellia thuanana was discovered at only the type locality with two individuals that are located under-canopy in an evergreen broadleaf forest at 750-800 m elevation. It grows with species of Fagaceae, Fabaceae, Anacardiaceae, Rubiaceae, and Sapotaceae.

IUCN Redlist Category
The area of occupancy for C. thuanana is estimated to be less than 1 km 2 . Despite a further search of the area around the type locality, only two mature trees were found. Field trips in the habitat area did not find more individuals. As the total known population of the species is fewer than 50 individuals, it qualifies as Critically Endangered (CR) under criterion D (IUCN Standards and Petitions Committee, 2019).
C. thuanana contains features typical of sect. Chrysantha by Chang (1981) such as styles completely free, flowers yellow, ovaries 3-5 locular, partially connate (Chang, 1981;Chang & Bartholomew, 1984). The complexity of sect. Chrysantha was discussedin further detail by Minh and Zhang (1993). Most species of sect. Chrysantha with yellow flowers were transferred to other sections, mainly sect. Archecamellia, with six species and two varieties (Minh & Zhang, 1993). Ming and Bartholomew (2007) combined sect. Chrysantha into sect. Archecamellia. In 2009, sect. Chrysantha was found to be paraphyletic because all golden camellias were combined into a single clade by the molecular analysis of Camellia, which was only accomplished by sampling from China and Taiwan together with C. gilbertii from Vietnam and C. assamica from Thailand (Vijayan et al., 2009). Orel and Curry (2015) still accept sect. Chrysanthae Sealy as an independent section (sect. Chrysantha). We accept C. thuanana belong to sect. Chrysantha by Chang (1981) because of the morphological features and molecular analysis of Vijayan et al. (2009).
Taxonomic Remarks: C. thuanana resembles C. thuongiana in morphological characteristics, such as mainly axillary and solitary flowers, semiorbicular to suborbicular sepal shape, petals and filaments glabrous, ovary 3 loculi and pubescent, styles 3 and glabrous ( Figure 2). The new species differs from C. thuongiana by its oblong-elliptic leaves with hirsute along the midrib below, leaf apex attenuates, shorter and pubescent petiole, smaller flowers, sepals puberulous inside, 7-8 petals, 3-4 circles and shorter stamen, nearly rounded petal, and freestyle to the base. A morphological comparison of C. thuanana and C. thuongiana is given in Table 1.  Styles 3, free to the base, 5-6.5 mm long, glabrous 3, free to ½ from the base, 8-9 mm long, glabrous