Corresponding author: Nian-He Xia (
Academic editor: Yun-Hong Tan
A new genus of
Tong Y-H, Zheng X-R, Zhang YY, Qin Q-M, Ni J-B, Vu TC, Xia N-H (2020)
Bamboos, including a single evolutionary radiation of 1,642 species in the grass family
During an investigation of the bamboos in Hon Ba Nature Reserve, Khanh Hoa Province of central-southern Vietnam in October 2017, an unusual bamboo with unicaespitose habit, scandent stems, pachymorph rhizomes and semelauctant inflorescences on leafy flowering branches caught our attention. This species was misidentified as
Comparison of morphological characters, distributions and habitats of
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Habit | Scrambling | Pendulous or procumbent | Scrambling |
Branching pattern | Extravaginal | Extravaginal | Transferring |
Nodes | Swollen at one side | Nearly flat | Swollen at one side |
Mid-culm branch complement | One central dominant branch accompanied by 1–4 lateral slender ones | 3–7 branches, subequal | Several to numerous branches, subequal, or one or three dominant branches accompanied by numerous slender ones |
Bud | Elliptic, wholly sunken into culm | Elliptic, wholly sunken into culm | Ovate to broad ovate, not sunken or only base sunken into culm |
Culm sheath base | Swollen, with a distinctive zone of transverse wrinkles | Flat, without a distinctive zone of transverse wrinkles | Usually swollen, without a distinctive zone of transverse wrinkles |
Culm sheath auricles | Absent | Present, falcate, amplexicaul | Absent or present |
Culm sheath oral setae | Absent | Present, radiate | Absent or present |
Presence of dots on culm | With brownish green dots | Without dots | Without dots |
Leaf auricles and oral setae | Absent | Present | Absent or present |
Synflorescence | Composed of only one spikelet, single or several to many synflorescences arranged into a raceme or panicle on leafy flowering branches | Racemose, composed of 1 or few spikelets, single synflorescence on leafy flowering branches | Paniculate, composed of many spikelets, on leafy or leafless flowering branches |
Glumes | (0–)1–2 | Unknown | 2 |
Number of florets per spikelet | 7–9 | 5 | 2–7 |
Anther color | Purple | Purple | Yellow |
Caryopsis | Nut-like, with hardened pericarp and loosely adherent lemma and palea | Unknown | Grain-like, without hardened pericarp and with closely adherent lemma and palea |
Distribution | Central-southern Vietnam | Southwest China (Guizhou) | South and Southwest China (Gansu, Chongqing, Sichuan, Guizhou, Yunnan, Hainan) |
Habitat | Granite montane, alt. 1500 m | Limestone montane, alt. 500–950 m | Limestone, granite or basalt montane, alt. 200–1800 m |
The nuclear gene GBSSI (granule-bound starch synthase I) occurs as a single copy in
Samples of this putative new species were collected for morphological and molecular phylogenetic studies from the only known population in Hon Ba Nature Reserve, Khanh Hoa Province, central-southern Vietnam during our field investigation in Oct. 2017. Photographs were taken with a CANON EOS 60D camera and dried flowers were dissected and examined under an Olympus SZX16 Microscope; line drawings and descriptions were made by reference to dried specimens.
Total genomic DNA was isolated from silica gel-dried leaf material using the Plant Genomic DNA Extraction Kit (Tiangen, Beijing, China), following the manufacturer’s instructions. The nuclear GBSSI sequence was amplified following the protocol used in
In addition, sequences from the other 42 taxon representing nearly all known genera of
Voucher information and GenBank accession numbers for taxa used in this study.
Taxon | Voucher no. | Source | GenBank accession no. (GBSSI) |
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Zhang 08035 (KUN) | Guangdong, China |
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Zhang 08065 (KUN) | Fujian, China |
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Zeng and Zhang 06054 (KUN) | Hainan, China |
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Zhang US1025 (KUN) | Arkansas, United States |
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Triplett 173 (ISC) | South Carolina, United States |
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Zhang KMBG09 (KUN) | Yunnan, China |
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Zhang 07092 (KUN) | Sichuan, China |
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Zeng and Zhang SB5 (KUN) | Yunnan, China |
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Zeng and Zhang 06174 (KUN) | Zhejiang, China |
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Zhang 07091 (KUN) | Sichuan, China |
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Zhang 07057 (KUN) | Yunnan, China |
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Zhang 07071 (KUN) | Yunnan, China |
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GLM 081860 (KUN) | Xizang, China |
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DZL 199903 (KUN) | Kew, Britain |
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Zhang 07087 (KUN) | Hubei, China |
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Zhang 07048 (KUN) | Yunnan, China |
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Zhang KMBG10 (KUN) | Sichuan, China |
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Zeng and Zhang SB1 (KUN) | Yunnan, China |
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JRX 9401 (KUN) | Yunnan, China |
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Zeng and Zhang 06183 (KUN) | Zhejiang, China |
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GLM 081524 (KUN) | Xizang, China |
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Zhen-Hua Guo 013 (KUN) | GenBank |
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Zeng and Zhang 06081 (KUN) | GenBank |
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Zeng and SD Zhang 07119 (KUN) | GenBank |
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Zhang 07014 (KUN) | GenBank |
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BVN2017048 (IBSC) | Vietnam |
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LL07236 (KUN) | Xizang, China |
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Triplett and Clark (2010), ZHZ200101 (KUN) | Locality unkown |
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Zhang 07024 (KUN) | Guangxi, China |
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MPF10052 (KUN) | Guizhou, China |
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MPF10142 (KUN) | Chongqing, China |
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MPF10123 (KUN) | Chongqing, China |
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Zhang 07075 (KUN) | Yunnan, China |
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Zhen-Hua Guo 013 (KUN) | Yunnan, China |
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Zhang KMBG04 (KUN) | Yunnan, China |
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Zhang and Zeng 06157 (KUN) | Zhejiang, China |
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Zhang and Zeng 06136 (KUN) | Zhejiang, China |
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Zhang 07023 (KUN) | Guangxi, China |
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Triplett 146 (KUN) | Tennessee, United States |
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Zhang and Zeng 06090 (KUN) | Guangdong, China |
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GLM 081775 (KUN) | Xizang, China |
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Zeng and Zhang 06108 (KUN) | Hunan, China |
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Zhang 08005 (KUN) | Sichuan, China |
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Gaps were coded as present or absent using the simple indel coding method (
Phylogenetic analyses were conducted with PAUP*v.4.0b10, MrBayes 3.2.5 (
ML analyses were conducted using GARLI 2.0 (
BI analyses were conducted using MrBayes 3.2.5 (
A total of 1414 characters were included in the maximum parsimony (MP) analyses matrix, of which 133 characters were parsimony-informative, 238 variable characters were parsimony-uninformative and 843 characters were constant. The strict consensus tree for the 234 most parsimonious trees (tree length = 531; CI = 0.787; RI = 0.675; RC = 0.532) is shown in Fig.
The strict consensus of 234 equally most parsimonious trees based on the partial GBSSI gene. Numbers below branches indicate posterior probability of Bayesian Analysis, and numbers above branches indicate bootstrap values of MP and ML.
In the current study, the monophyly of the temperate woody bamboo clade was strongly supported, with 100% MPBS, 100% MLBS and 1.00 PP. Our putative new species was nested in the monophyletic clade of
Shrubby bamboo. Rhizomes pachymorph, short-necked. Culms unicaespitose, erect at lower part, distally scrambling; internodes terete, with dense brownish green dots; nodes conspicuous, swollen at one side. Buds elliptic, wholly sunken into culm. Branches extravaginal, often solitary at lower part of culm, and usually with one central dominant branch elongating to reiterate the culm and 1–4 lateral slender ones in the middle part of culm. Culm sheaths persistent, basally swollen, with a distinctive zone of transverse wrinkles; auricles and oral setae absent; blade reflexed; ligule convex. Foliage leaves without auricles and oral setae; ligules convex. Synflorescence semelauctant, composed of only one spikelet subtended by one or several sheath-like bracts, single or several to many synflorescences arranged into a raceme or panicle which is terminal on leafy branches; spikelets with 8–9 florets. Glumes (0-)1–2. Palea slightly shorter than lemma. Lodicules 3. Stamens 3, filaments free, anthers purple. Styles 2, free, stigmas 2, plumose. Caryopsis nut-like, with a hardened pericarp and loosely adherent lemma and palea, apex with 2 persistent style bases.
Vietnam, Khanh Hoa, Hon Ba Nature Reserve, 1500 m, 17 October 2017, N. H. Xia et al. BVN2017048 (holotype, IBSC!; isotypes, SING!, VNM!).
Culms erect at lower part, distally scrambling, 2–4(-10) m long; internodes terete, 20–32 cm long, 4–6 mm in diam., initially light purple, becoming gray-green, with dense brownish green dots turning black when dry; nodes conspicuous, swollen at one side, lower margin ciliate, supranodal ridge inconspicuous, intranodes glabrous. Buds elliptic, wholly sunken into culm. Branches extravaginal, often solitary at lower part of culm, and usually with one central dominant branch elongating to reiterate the culm and 1–4 lateral slender ones in the middle part of culm, lateral branches 10–25 cm long. Culm sheaths persistent, leathery, glossy, initially light purple, 8–9.5 cm long, abaxially with distinct veins, basally swollen, with a distinctive zone of transverse wrinkles; auricles and oral setae absent; blade reflexed, lanceolate, 6–9 cm long, glabrous, deciduous; ligule convex, ca. 2 mm high, glabrous. Leaves 3–8 per ultimate branch; leaf sheaths glabrous; auricles and oral setae absent; ligules convex, ca. 2 mm high; blades elliptic-lanceolate, 10–20 × 1–2.5 cm, glabrous both sides except margin ciliate at the base when young, secondary veins 3–5 pairs, transverse veins distinct. Synflorescence semelauctant, composed of only one spikelet subtended by one or several sheath-like bracts, single or several to many synflorescences arranged into a raceme or panicle which is terminal on leafy branches; spikelets 4–7 cm long, florets 8–9. Glumes (0-)1–2, ovate, ca. 10 × 3 mm, apex acute, glabrous, 11-veined. Rachilla segments flat, ca. 6 mm, glabrous, apex inflated. Lemma ovate-lanceolate, 12–13 × 5 mm, glabrous, 13-veined, apex acute with a mucro; palea slightly shorter than lemma, 11–12 × 2–3 mm, 2-keeled, keels ciliolate, apex with excurrent keel vein, 3-veined between keels and 2-veined outside keels, veins inconspicuous; lodicules 3, ovate, membranous, 3–5 × 1.5–2 mm, ciliolate, apex acuminate; stamens 3, filaments white, free, anthers tinged purplish when young, then becoming purple, ca. 7 mm long; ovary ovoid, 1 mm long, glabrous; styles 2, free, ca. 1 mm long, stigmas plumose, ca. 3 mm long. Caryopsis nut-like, with a hardened pericarp and loosely adherent lemma and palea, dark brown, fusiform, 8–9 × ca. 3 mm, apex with 2 persistent style bases.
This species was only found in the type locality, i.e. Hon Ba Nature Reserve, Khanh Hoa Province of Vietnam. It occurs in high mountain broadleaved forests at an elevation of ca. 1500 m.
(paratype): VIETNAM, Khanh Hoa, Hon Ba Nature Reserve, 12°06'39.2"N, 108°56'47.2"E, C. Y. Lee et al. HIKK370 (HN!).
Morphological analysis (Table
Comparison of culm leaf sheath bases
Comparison of buds
The authors are grateful to Mr. Ngyuen Van Dat and the staff in Hon Ba Nature Reserve for their help during the field trip. Our thanks also go to Dr. Joongku Lee for his help during locating the paratype specimen. This study was funded by the National Natural Science Foundation of China (grant nos. 31670196 & 31870180), Regional International Cooperation Project of Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (grant no. 2016CASSEABRIQG008) and Provincial Science and Technology Planning Project of Guangdong (grant no. 2017A030303061).