Research Article |
Corresponding author: Yongqing Liufu ( lfyongqing@foxmail.com ) Academic editor: Clifford Morden
© 2019 Renchuan Hu, Sujuan Wei, Yongqing Liufu, Yunkai Nong, Wei Fang.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hu R, Wei S, Liufu Y, Nong Y, Fang W (2019) Camellia debaoensis (Theaceae), a new species of yellow camellia from limestone karsts in southwestern China. PhytoKeys 135: 49-58. https://doi.org/10.3897/phytokeys.135.38756
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Camellia debaoensis R.C.Hu & Y.Q.Liufu, sp. nov. is described and illustrated as a new species from southwestern Guangxi, China. It is morphologically similar to Camellia pubipetala Y. Wan & S. Z. Huang, C. mingii S.X. Yang and C. tuyenquangensis D.V. Luong, N.N.H. Le & N. Tran, but it differs from these species in having glabrous young branches, glabrous petiole, glabrous sepals, glabrous petals, glabrous stamens and glabrous ovary, 10 petals, cylindrical ovary and style 3-lobed to 1/6 style length.
Camellia, China, limestone flora, taxonomy, Theaceae
Guangxi Zhuang Autonomous Region of southern China is an area noted for its karst landscapes (
During our floristic survey in limestone karsts of Debao County, southwestern Guangxi, in 2015, we collected several specimens from a population of Camellia with yellow flowers. In the following three years, this population was documented for flowering and fruiting regularly at the same locality. Morphological comparison between the newly collected specimens and other yellow camellias suggested that the specimens from Debao differed from all the previously described species. Therefore, we here describe this material as a new species.
Several specimens were collected at the entrance of one of the karst caves of Debao County, Jingde Town, Tuoliang village from 2015 to 2018, and were deposited in the herbaria GXMI, IBK, NHMG, KUN. The morpho-photographs of the plants were taken with a Panasonic LX100 camera. This material was confirmed as a new species based on detailed comparison with all other heretofore known yellow camellias, including specimens deposited at PE, KUN, IBSC, IBK, GXMI, HIB, SYS, GXMG, and description from botanical websites (e.g. http://www.cvh.ac.cn/, https://plants.jstor.org/). Herbarium acronyms follow
Morphologically, the new species is similar to Camellia pubipetala Y. Wan & S.Z. Huang, C. mingii S.X. Yang and C. tuyenquangensis D.V. Luong, N.N.H. Le & N. Tran, but it differs from these species in having glabrous young branches, glabrous petiole, glabrous sepals, glabrous petals, glabrous stamens and glabrous ovary, 10 petals, cylindrical ovary and 3-lobed to 1/6 style length.
China. Guangxi Zhuang Autonomous Region: Debao County, Jingde Town, Tuoliang village, at the entrance of one of karst caves, rare, 23°29'23.12"N, 106°9'47.27"E, 760 m a.s.l., 13 January 2017 (fl.), R.C. Hu HRC170113002 (holotype: GXMI!, isotypes: GXMI!, KUN!, NHMG! and IBK!).
Shrubs, 1–3 m tall. Young branches cylindrical, thick, glabrous, yellowish brown or grayish brown, and current year branchlets purplish red. Leaf blade leathery, ovate to long ovate, 6–13 × 3–5 cm, adaxial surface dark green and glabrous, abaxial surface pale green, brown glandular punctuate and veins sparsely spreading villous, veins abaxially elevated and adaxially impressed, secondary veins 5–6 on each side of midvein and connected at the proximal edge, base cuneate to broadly cuneate, apex caudate tip, margin serrulate; petiole 5–12 mm long, glabrous. Flowers subterminal axillary, solitary, 3–4.5 cm diam. Pedicel ca. 4(–6) mm long, thick; bracteoles 4 (or 5), unequal, 1–3 × 2–4 mm, appressed and covering pedicel, oval-triangle, leathery, green and glabrous, margin ciliolate. Sepals 5 (–6), semiorbicular to broadly ovate, 3–5 × 5–8 mm, leathery, glabrous, lightly yellow and occasionally with pink patches, fruiting stage green, margin ciliolate. Petals 10, in three whorls of 3–4 petals, golden yellow, glabrous; outer 3 or 4 petals suborbicular, occasionally with pink patches, 0.7–1.1 × 1 cm; inner orbicular-ovate or oval, 1.2–1.8 × 1.2–2.6 cm, basally connate for 1–3 mm. Stamens numerous, glabrous, ca. 2 cm long; anthers ca. 3 × 1mm; outer filaments connate ca. basal 1/4, ca. 1.6 cm, inner filaments nearly distinct, ca. 1.7 cm. Ovary cylindrical, ca. 2 mm in diam., glabrous, 3-loculed; style 2 cm long, glabrous, base connate, apex 3-lobed to 1/6 style length. Capsule triangle oblate, glabrous, 1.4–1.6 × 1.6–2.8 cm; Seeds brown, hemispherical, pubescent.
Flowering from December to February of the next year; fruiting from July to August.
Camellia debaoensis grows at the entrance of one of the limestone caves in the karst region of Debao County (Fig.
According to currently available data, Camellia debaoensis is only found in its type locality and there are only nine adult trees and four saplings, with the distribution restricted to a very limited region (less than 200 m2). Considering this situation, we consider Camellia debaoensis as ‘Critically Endangered’ (CR) based on the IUCN categories and criteria (
China. Guangxi Zhuang Autonomous Region: Debao County, Jingde Town, Tuoliang village, at the entrance of karst cave, rare, ca. 760 m a.s.l., 13 Jan. 2017 (fl.), R.C. Hu HRC170113001 (GXMI!); the same locality, 21 May 2016 (fr.), R.C. Hu HRC170521001 (GXMI!); the same locality, 25 Dec. 2015 (fl.), R.C. Hu & Y.Q. Liufu HRC151225023 (GXMI!).
The specific epithet is derived from the type locality, Debao County, Guangxi.
It is noted that there are several classification systems about taxonomic treatments of Camellia, represented by
Camellia debaoensis resembles many other yellow-flowering camellia species with connate style, such as Camellia pubipetala Y. Wan & S.Z. Huang, C. mingii S.X. Yang, C. tuyenquangensis D.V. Luong, N.N.H. Le & N. Tran, C. oconariana Orel, Curry & Luu, C. thuongiana Luong, Anna Le & Lau, C. luteocerata Orel, C. luteopallida Luong, T.Q.T. Nguyen & Luu, C. bugiamapensis Orel, Curry, Luu & Q.D. Nguyen and C. capitata Orel, Curry & Luu. These species are placed in various sections within the genus including sections Stereocarpus Chang, Chrysantha Chang, Dalatia Orel and Capitatae Orel (Table
Morphological comparison of C. debaoensis with other yellow camellias with connate style. Data from
Taxon | Section | Leaf shape, leaf size | Pedicel length | No. of bracts | No. of petals | Style, extent to which cleft, hairiness | Ovary, carpels, hairiness | Filaments morphology |
---|---|---|---|---|---|---|---|---|
C. capitata | Capitatae | Elliptic to oval, 24.0–27.0 × 10.0–12.0 cm | Sessile | 8–10 | 6 | Apex 3-lobed, apically cleft for 1–2 mm, glabrous | 3-carpellate, glabrous | Glabrous, outer filaments basally attached to inner petals for ca. 10 mm |
C. luteocerata | Dalatia | Elliptic to broadly elliptic, 22.0–27.5 × 9.0–11.0 cm | Sessile | 6 | 11–13 | Apex 5-lobed, apically cleft to 1/3 style length, glabrous | 5-carpellate, glabrous | Glabrous, filaments basally connate for 1/3 of their length, and partially joined to the inner petals |
C. bugiamapensis | Dalatia | Elliptic, oval to widely elliptic, 18.0–27.5 × 12.0–14.0 (–15.0) cm | Sessile | 7 | 9–11 | Apex 5-lobed, apically shortly lobed, white hairs | 5–6-carpellate, glabrous | Glabrous, outer filaments basally attach to inner petals for 20–25 mm |
C. luteopallida | Dalatia | Elliptic to ovate, 16.0–20.0 × 5.0–9.0 cm | Sessile | 6–9 | 12–14 | Apex 3-lobed, apically cleft 3–6 mm, dense white hairs | 3-carpellate, glabrous | Sparely hairy, filaments basally united to each other to form a 10–13 mm fleshy tube |
C. tuyenquangensis | Chrysantha | Oblong ovate to narrow elliptic, 14.0–18.0 × 5.0–8.0 cm | 10 mm | 4–5 | 12 | Apex 3-lobed, apically cleft to 1/2 style length, glabrous | 3-carpellate, glabrous | Glabrous, outer filament whole basally connate for 10–14 mm, adnate to petal base |
C. thuongiana | Chrysantha | Elliptic to oblong elliptic, 9.0–17.0 × 4.0–6.5 cm | 8–10 mm | 3–4 | 11–13 | Apex 3-lobed, apically cleft to 1/2 style length, glabrous | 3-carpellate, pubescent | Glabrous, outer filaments basally connate for 4–5 mm |
C. oconoriana | Chrysantha | Narrowly elliptic, 30.0–36.5 × 8.0–8.5 cm | 30–40 mm | 6 | 6 | Apex 3–5-lobed, apically cleft 9–11 mm, finely hairy proximally, glabrous distally | 4–5-carpellate, densely tomentose | Glabrous, outer filaments basally connate for ca. 6 mm |
C. pubipetala | Stereocarpus | Elliptic to ovate, 10.0–17.0 × 5.0–8.0 cm | Subsessile | (4–)6–8 | 9–13 | Apex 3(or 4)-lobed, apically cleft 5–10 mm, tomentose | 3(or 4)-loculed, yellowish tomentose | Distinct part pilose, outer filament whorl basally connate for ca. 1/3 of its length |
C. mingii | Stereocarpus | Elliptic-ovate to narrowly ovate, 10.0–15.0 × 4.0–6.0 cm | 3–6 mm | 4 or 5 | 12 or 13 | Apex 3-lobed, apically cleft ca.2–3 mm, glabrous or sparsely pubescent | 3-carpellate, densely tomentose | Puberulent, outer filaments basally connate for ca. 1/2 of their length |
C. debaoensis | Stereocarpus | Oval to long oval, 6.0–13.0 × 2.5–5.0 cm | 4(–6) mm | 4 (or 5) | 10 | Apex 3-lobed, apically cleft to 1/6 style length, glabrous | 3-carpellate, glabrous | Glabrous, outer filaments basally connate for ca. 1/4 of their length |
Morphological comparison of C. debaoensis with C. pubipetala, C. mingii and C. tuyenquangensis.
Items | C. debaoensis | C. pubipetala | C. mingii | C. tuyenquangensis |
---|---|---|---|---|
Young branches | Glabrous | Gray spreading villous | Densely spreading yellowish villous | Glabrous |
Leaf | Ovate to long ovate, 6.0–13 × 2.5–5.0 cm, abaxial veins sparsely spreading villous, secondary veins 5–6 | Elliptic-ovate, 10.0–17.0 × 5.0–8.0 cm, abaxial appressed villous but densely spreading villous along midvein, secondary veins 8–10 | Elliptic-ovate to narrowly ovate, 10.0–15.0 × 4.0–6.0 cm, abaxial densely spreading villous along veins, secondary veins 7–10 | Oblong ovate to narrow elliptic, 14.0–18.0 × 5.0–8.0 cm, abaxial glabrous, secondary veins 9–11 |
Petiole | 5–12 mm long, glabrous | 5–10 mm long, villous | 5–7 mm long, densely villous | 10–15 mm long, glabrous |
Pedicel length | 4 (–6) mm | 3–5 mm | 3–6 mm | 10 mm |
Sepals | Glabrous | Densely puberulent | Inside densely puberulent | Glabrous |
Petals | 10, glabrous | 9–13, outside gray puberulent, inside glabrous | 12 or 13, puberulent on both surfaces | 12, glabrous |
Stamens | 2.0 cm long, glabrous | 2.5–3.0 cm long, distinct part pilose | 3.0 cm long, puberulent | 2.5–3.0 cm long, glabrous |
Ovary | Cylindrical, glabrous | Spherical, densely tomentose | Ovoid, densely tomentose | Ovoid, glabrous |
Style | 2 cm long, apex 3-lobed to 1/6 style length, glabrous | Apically 3 (or 4)-lobed to 1/3 style length, tomentose | 3.0 cm long, apex 3-cleft to 1/10 style length, glabrous | 3 cm long, apex 3-cleft to 1/2 style length, glabrous |
1 | Ovary 3 carpellate, style 3-parted; if ovary 3 (or 4) carpellate, style 3 (or 4)-parted, young branches and leaves spreading villous (C. pubipetala) | 2 |
– | Ovary 4–6 carpellate, style (3–) 4–6-parted | 8 |
2 | Petals 9–14 | 3 |
– | Petals 6 | C. capitata |
3 | Young branches, petiole, petals, stamens, ovary and style piliferous | 4 |
– | Young branches, petiole, petals, stamens, ovary and style glabrous | 5 |
4 | Petals puberulent on both sides, suborbicular | C. mingii |
– | Petals adaxial puberulent, inside glabrous, elliptic | C. pubipetala |
5 | Petals with dense appressed brown hairs; style with dense white appressed hairs | C. luteopallida |
– | Petals and style glabrous | 6 |
6 | Leaf 6–13 × 2.5–5 cm, abaxial veins sparsely spreading villous, secondary veins 5–6; ovary cylindrical; style apex 3-lobed to 1/6 the length of style | C. debaoensis |
– | Leaf glabrous; style apex 3-cleft to 1/2 the length of style | 7 |
7 | Stamens 2.5–3 cm long; style 30 mm long | C. tuyenquangensis |
– | Stamens 1.3–1.4 cm long; style 8–9 mm long | C. thuongiana |
8 | Leaf secondary veins 8–11; pedicel sessile, 1–5 mm long | 9 |
– | Leaf secondary venation 24 pairs; pedicel 30–40 mm long | C. oconoriana |
9 | Petals 9–11, with margins sparsely ciliate; style finely tomentose | C. bugiamapensis |
– | Petals 11–13, outer 5-petaloid concave; style glabrous | C. luteocerata |
We are grateful to Xu Weibin (Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and the Chinese Academy of Sciences, Guilin) for useful comments on the manuscript, Huang Xiaona, Jiang Changjie and Professor Huang Liangdong (Nanning Golden Camellia Park, Nanning) for species diagnosis, Yang Ping, Wei Guiyuan and Lan Xiangchun (Guangxi Institute of Traditional Medical and Pharmaceutical Sciences, Nanning) for fieldwork assistance, Qu Xincheng for the line drawing. This work was partially supported by the 2017 Chinese Medicine Public Health Service Subsidy Special “National Chinese Medicine Resources Census Project” (GXZYZYPC17-3), the National Natural Science Foundation of China (31760088), the Guangxi Key Laboratory of Traditional Chinese Medicine Quality Standards Independent research topic (GZZZ201605), the Guangxi Science and Technology Project (guike AD16380013).