Research Article |
Corresponding author: Nian-He Xia ( nhxia@scbg.ac.cn ) Academic editor: Weilim Goh
© 2023 Yi-Hua Tong, Zheng-Yang Niu, Zhuo-Yu Cai, Jing-Bo Ni, Nian-He Xia.
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:
Tong Y-H, Niu Z-Y, Cai Z-Y, Ni J-B, Xia N-H (2023) Kengiochloa, a new bamboo genus to accommodate the morphologically unique species, Pseudosasa pubiflora (Poaceae). PhytoKeys 221: 131-145. https://doi.org/10.3897/phytokeys.221.98920
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Pseudosasa was confirmed as polyphyletic by recent phylogenetic analyses, with Chinese species of Pseudosasa distantly related to those from Japan. Among the Chinese species of Pseudosasa, Pseudosasa pubiflora is a morphologically unique as well as taxonomically problematic species endemic to South China, of which the generic designation is still uncertain. Molecular analyses based on both plastid and nuclear genomic data demonstrated that this species is closest to the recently published genus Sinosasa. Morphologically, the two are somewhat similar to each other in flowering branches developing at the nodes of every order of branches, raceme-like units of inflorescence with 3–5 short spikelets, each spikelet with few florets including a rudimentary one at the apex, and each floret with 3 stamens and 2 stigmas. However, P. pubiflora is very different from Sinosasa species in many reproductive and vegetative characters, such as the morphology of paracladia (lateral spikelet “pedicels”), the absence or existence of pulvinus at the base of paracladia, the relative length of the upper glume and the lowest lemma, the shape of lodicules and primary culm buds, the branch complement, the morphology of nodes, culm leaves and dried foliage leaf blades, and the number of foliage leaves per ultimate branchlet. The morphological and molecular evidence warrants recognition of a new genus to accommodate this unique species, which is here named Kengiochloa. After consulting related literature and examination of herbarium specimens or specimen photos, a taxonomic revision of K. pubiflora and its synonyms was made, and it was confirmed that four names, viz. P. gracilis, Yushania lanshanensis, Arundinaria tenuivagina and P. parilis, should be merged with K. pubiflora, while Indocalamus pallidiflorus and Acidosasa paucifolia are distinct species.
morphology, phylogeny, plastome, synonyms, taxonomy
Pseudosasa Makino ex Nakai, with ca. 20 species mainly distributed in East Asia and Vietnam, belongs to the subtribe Arundinariinae of the tribe Arundinarieae (Poaceae: Bambusoideae) (
Pseudosasa pubiflora has a relatively complicated taxonomic history. In 1936, Yi-Li Keng, the first Chinese botanist who studied the bamboo classification in China, described Arundinaria pubiflora Keng from northern Guangdong based on only one collection (To & Tsang 12284) with flowers (
The P. pubiflora published in Flora of China (
Field trips to the type locality of P. pubiflora as well as its several synonyms including I. pallidiflorus, Arundinaria teuivagina and P. parilis were conducted from 2018 to 2022. The complete specimens including rhizomes, culms with culm leaves, branches and foliage leaves as well as fresh young foliage leaves used for molecular analyses were collected. The types and other specimens of the pertinent species housed at CANT, IBSC, N, SYS and ZJFI, as well as photographs of specimens housed at K, US and W, were examined. Herbaria acronyms follow
To study the phylogenetic position of P. pubiflora within the tribe Arundinarieae, the whole chloroplast genomes were used for building the phylogenetic tree. Five Pseudosasa species including one from Japan, also the type species of the genus, viz. P. japonica, and four from China were sampled. In total, there were 29 species represented by 30 samples of all the five subtribes in the tribe Arundinarieae (two samples for P. pubiflora) and one sample of Bambusa bambos (L.) Voss from the tribe Bambuseae was the outgroup. Species names, voucher information and GenBank accession numbers are provided in Table
Species names, voucher information and GenBank accession numbers of the 30 whole chloroplast genomes used in this study.
Taxon | Voucher information | GenBank accession |
---|---|---|
Ingroup | ||
Acidosasa glauca B. M. Yang | CZY56 (IBSC) | *OP850353 |
Ampelocalamus actinotrichus (Merr. & Chun) S. L. Chen T. H. Wen & G. Y. Sheng | MPF10003 (KUN) | MF066245 |
Chimonobambusa quadrangularis (Franceschi) Makino | Not provided by the author | MW928533 |
Ferrocalamus rimosivaginus T. H. Wen | Zhang08019 (KUN) | HQ337794 |
Ferrocalamus strictus Hsueh & Keng f. | NH001 (IBSC) | *OP850355 |
Gaoligongshania megalothyrsa (Hand.-Mazz.) D. Z. Li, Hsueh & N. H. Xia | MPF10056 (KUN) | JX513419 |
Gelidocalamus stellatus T. H. Wen | BH102 (IBSC) | *OP850347 |
Gelidocalamus tessellatus T. H. Wen & C. C. Chang | MPF10049 (KUN) | JX513420 |
Hsuehochloa calcarea (C. D. Chu & C. S. Chao) D. Z. Li & Y. X. Zhang | MPF10050 (KUN) | KJ496369 |
Indocalamus longiauritus Hand.-Mazz. | MPF10168 (KUN) | HQ337795 |
Indocalamus latifolius (Keng) McClure | CZY76 (IBSC) | *OP850354 |
Indocalamus sinicus (Hance) Nakai | ZMY037 (KUN) | MF066250 |
Indosasa crassiflora McClure | BH58 (IBSC) | *OK558536 |
Phyllostachys nidularia f. farcta H. R. Zhao & A. T. Liu | 2020-JZ01 (NF) | LC590826 |
Pleioblastus chino (Franch. & Sav.) Makino | NH029 (IBSC) | *OP850356 |
Pseudosasa amabilis (McClure) Keng f. | NH032 (IBSC) | *OP850358 |
Pseudosasa cantorii (Munro) Keng f. | MPF10006 (KUN) | MF066255 |
Pseudosasa japonica (Siebold & Zucc. ex Steud.) Makino ex Nakai | Pjc-1 (ZJFC) | KT428377 |
Pseudosasa nanunica (McClure) Z. P. Wang & G. H. Ye | XNH36 (IBSC) | *OP850361 |
Pseudosasa pubiflora (Keng) Keng f. ex D. Z. Li & L. M. Gao | CZY146 (IBSC) | *OP850350 |
Pseudosasa pubiflora (Keng) Keng f. ex D. Z. Li & L. M. Gao | XNH63 (IBSC) | *OP850362 |
Shibataea chinensis Nakai | NH036 (IBSC) | *OP850359 |
Sinobambusa tootsik (Makino) Makino ex Nakai | NH031 (IBSC) | *OP850357 |
Sinosasa fanjingshanensis N. H. Xia, Q. M. Qin & J. B. Ni | BH124 (IBSC) | *OP850348 |
Sinosasa sp. | CZY173 (IBSC) | *OP850352 |
Sinosasa longiligulata (McClure) N. H. Xia, Q. M. Qin & J. B. Ni | CZY163 (IBSC) | *OP850351 |
Ravenochloa wilsonii (Rendle) D. Z. Li & Y. X. Zhang | MPF10146 (KUN) | JX513421 |
Oligostachyum sulcatum Z. P. Wang & G. H. Ye | CZY113 (IBSC) | *OP850349 |
Yushania basihirsuta (McClure) Z. P. Wang & G. H. Ye | XNH144 (IBSC) | *OP850360 |
Outgroup | ||
Bambusa bambos (L.) Voss | B1-1 (ISC) | KJ870988 |
Total genomic DNA was isolated from silica gel-dried leaves using TIANGEN Genomic DNA Extraction Kit (TIANGEN, Beijing, China). The extracted genomic DNA was fragmented randomly by Covaris M220 (Covaris, Woburn, MA), and the fragments with insert size of 350 bp were selected by using AxyPrep Mag PCR Clean Up Kit. The selected fragments were enriched by PCR after undergoing end repair, the addition of polyA tail and adaptor ligation. The paired-end (2 × 150 bp) libraries were constructed on NovaSeq 6000 platform. Finally, 20 Gb genome skimming data were generated for each sample.
After quality control of 20 Gb clean data by Trimmomatic v 0.39 (
All the cp genomes were aligned using MAFFT v. 7.450 (
The chloroplast genomes ranged from 139,093 bp (Pleioblastus chino Makino) to 140,064 bp (Gaoligongshania megalothyrsa (Hand.-Mazz.) D. Z. Li, Hsueh & N. H. Xia) with an alignment length of 144,771 bp. The plastid data matrix was characterized by sequence divergence with 9,751 variable sites (6.74%), including 6,477 parsimony informative sites (4.47%) and 3,274 singleton variable sites (2.27%).
The reconstructed phylogenetic tree is shown in Fig.
After consulting related literature and examining the types and other herbarium specimens or specimen photographs, we agree with
Kengiochloa pubiflora A habitat B habit C leptomorph rhizome and pluricaespitose culms, the arrow showing an internode with a bud D culm leaf, the arrow showing the junction of sheath and blade E culm leaf oral setae F intravaginal branching G prophyll of primary branch H three young branches at a node I foliage leaf branch. Photos by Y. H. Tong.
However, we do not agree that I. pallidiflorus and Acidosasa paucifolia are identical to P. pubiflora. Indocalamus pallidiflorus (≡ Pseudosasa pallidiflora (McClure) S. L. Chen & G. Y. Sheng) markedly differs from P. pubiflora in the woolly (vs. glabrous) infranodal region, the culm leaf sheath oral setae present (vs. absent) and the culm leaf blade much shorter (vs. usually longer) than sheath. Actually, the description of P. pubiflora in Flora of China is mainly based on that of I. pallidiflorus made by
Recent research has proved that the formerly recognized Arundinaria in a broad sense should not be adopted any more, which at present is thought to be a small genus with only three species restricted to North America (
Comparison of key morphological characters of Pseudosasa pubiflora, Sinosasa, Indocalamus sinicus and Pseudosasa. The characters unique to P. pubiflora among these taxa are indicated in bold.
P. pubiflora | Sinosasa | Indocalamus sinicus | Pseudosasa | |
---|---|---|---|---|
Culm bud | Narrowly ovate | Trullate | Triangle, lower half adnate to culm | Trullate to narrowly trullate |
Branches at mid-culm nodes | 2 to 4 | Solitary | Solitary | 1 to 3 |
Nodes | Flat | Prominent, supranodal ridge strongly raised | Flat | Flat or weakly prominent |
Infranodal region | Glabrous, nonpowdery | With a sericeous or villous band | Glabrous, nonpowdery | Powdery |
Culm leaf sheath | Persistent, papery | Persistent, papery | Persistent, leathery-papery | Persistent, usually leathery |
Culm leaf oral setae | Adnate at base | Distinct | Distinct or absent | Distinct or absent |
Culm leaf blades | Erect, amplexicaul, usually longer than sheath | Erect or slightly spreading, not amplexicaul, much shorter than sheath | Erect or reflexed, not amplexicaul, narrowly triangular-lanceolate, much shorter than sheath | Erect or reflexed, amplexicaul or not, narrowly triangular to strap-shaped, shorter than or as long as sheath |
Number of foliage leaves per ultimate branchlet | 1 to 4 | 5 to 17 | 7 to 14 | 2 to 10 |
Inner ligule | Very short, 0.3–1.5 mm | Long, (8–)10–20 mm | Short, 2–3 mm | Short to long, 1–5 mm |
Foliage leaf blades | Flat when dry | Wavy when dry | Flat when dry | Flat when dry |
Flowering branch | Developing at the nodes of every order of branches | Developing at the nodes of every order of branches or culm | Terminal on culm or foliage leaf branches | Developing at the nodes of every order of branches or culm |
The unit of inflorescence of the synflorescence | Raceme-like with 3–5 spikelets | Raceme-like with 3–5 spikelets | Panicle-like with many spikelets | Raceme or panicle-like with several to many spikelets |
Paracladia | Robust and erect, appressed to the axis | Slender, porrect to reflexed | Slender, porrect | Slender, porrect |
Pulvinus at the base of pracladia | Absent | Present | Present | Absent |
Spikelet | Lanceolate, 1.6–2 cm long | Lanceolate, 0.5–1.5 cm long | Lanceolate, 1.5–2.5 cm long | Narrowly terete or linear, 2.5–20 cm long |
Number of floret per spikelet | 2–4 | 2–3 | 3–4 | 3–30 |
Terminate rudimentary floret | Exist | Exist | Exist | Exist or not |
The relative length of upper glume and the lowest lemma | Upper glume shorter than the lowest lemma | Upper glume nearly equal to the lowest lemma | Upper glume shorter than the lowest lemma | Upper glume shorter than the lowest lemma |
Lodicule | Oblong-obovate, spatulate or obovate, apex rounded | Ovate or narrow oblong, apex acute | Ovate to oblong, apex obtuse | Oblong, obovate-lanceolate, spathulate or lanceolate, apex acute or obtuse |
Stigma number | 2 | 2 | 2 | 3 to 5 |
Interestingly, both of the two phylogenetic studies suggested a close relationship between Pseudosasa pubiflora and Sinosasa. In the analysis of
Last, there are so many different vegetative and productive characters between Pseudosasa pubiflora and Sinosasa that they cannot belong to the same genus. Specifically, Pseudosasa pubiflora differs from Sinosasa in having narrowly ovate culm buds (vs. trullate) (Fig.
Kengiochloa pubiflora (Keng) Y. H. Tong & N. H. Xia (≡ Arundinaria pubiflora Keng).
This new genus is close to Sinosasa, but differs in having narrowly ovate culm buds, branch complement with 2–4 branches at mid-culm nodes, flat nodes, glabrous and nonpowdery infranodal region, culm leaf oral setae adnate at base, amplexicaul culm leaf blades that are usually longer than sheath, 1–4 foliage leaves per ultimate branchlet with blades flat when dry and short inner ligule, robust and erect paracladia (lateral spikelet pedicels) appressed to the axis and without pulvinus at base, upper lemma typically shorter than the lowest lemma and lodicules with a rounded apex.
Shrubby bamboo. Rhizomes leptomorph. Culms pluricaespitose, short and thin, less than 2 m tall and 8 mm in diam.; nodes flat. Culm buds narrowly ovate. Branches intravaginal, 2–4 at each mid-culm node. Culm leaf sheath persistent, papery; auricles absent; oral setae fragile, adnate at base; blade erect and amplexicaul, usually longer than sheath; ligule convex, short. Foliage leaves 1–4 per ultimate branchlet; auricles obscure; inner ligule short. Flowering branches developing at the nodes of every order of branches; the unit of inflorescence of synflorescence raceme-like with 3–5 spikelets; paracladia robust and erect, appressed to the axis and without pulvinus at base; florets 2–4 per spikelet including a rudimentary one at the apex; glumes 2, upper one shorter than the lowest lemma; lemma longer than palea; palea 2-keeled; lodicules 3, apex rounded; stamens 3, anthers pale yellow; styles 2, base slightly connate; stigmas 2, plumose. Caryopsis unknown.
Kengiochloa is named in honor of Professor Yi-Li Keng (1897–1975), a renowned botanist and the first Chinese who studied the bamboo taxonomy in China. The type species of this genus was first described by him, too. Its Chinese name is given as 以礼竹属 (pinyin: yĭ lĭ zhú shŭ).
≡Arundinaria pubiflora Keng, Sinensia 7: 414, fig. 4. 1936; Yang & Chao, J. Bamb. Res. 13(1): 5. 1994, excl. syn. of Indocalamus pallidiflorus. ≡ Pseudosasa pubiflora (Keng) Keng f. ex D. Z. Li & L. M. Gao in Zhu et al., Fl. China 22: 118. 2006, excl. descr. and syn. of Indocalamus pallidiflorus and Acidosasa paucifolia; Keng f. in Keng, Clav. Gen. Sp. Gram. Prim. Sin. 154. 1957 & Fl. Ill. Pl. Prim. Sin. 32 & pl. 22. 1959, nom. inval. Type: China, Guangdong, on top of the hill at the rear of Iu [Yao] village, Lung Tau Mt. [Longtou Mountain], 30 May 1924, To & Tsang 12284 (holotype US00130296 (sheet 1) & US00065420 (sheet 2), image!, isotypes US0031360, image!, US00144993, image!, W19390008723, image!, SYS!). Figs
=Pseudosasa gracilis S. L. Chen & G. Y. Sheng, Acta Phytotax. Sin. 21: 405. 1983; Chen et al., Fl. Reipubl. Popularis Sin. 9(1): 658. 1996; Zhu et al., Fl. China 22: 119. 2006. Type: China, Hunan, Yizhang County, Zeping, 6 May 1977, Z. P. Wang, H. R. Zhao & G. Y. Sheng 77004 (holotype NAS, not seen, isotypes N019022078!, N019022079!, N019022080!).
=Yushania lanshanensis T. H. Wen, J. Bamboo Res. 4(2): 13. 1985. ≡ Arundinaria lanshanensis (T. H. Wen) T. H. Wen, J. Bamboo Res. 5(1): 19. 1986. Type: China, Hunan, Lanshan County, Ziliang Township, 1125 m, 17 June 1984, S. Q. Chen CX84860 (holotype ZJFI!, isotypes ZJFI!).
=Arundinaria tenuivagina W. T. Lin & Z. M. Wu, J. S. China Agric. Univ. 11(3): 48. 1990. Type: China, Guangdong Province, Xinyi City, Dawuling, 1400 m, 12 April 1987, Z. M. Wu 0167 (holotype CANT00002410!, isotypes CANT00002408!, CANT00002409!, CANT00002411!, CANT00002412!, CANT00002413!, CANT00002414!, CANT00002415!).
=Pseudosasa parilis T. P. Yi & D. H. Hu in Yi, J. Bamboo Res. 14(1): 20. 1995. Type: China, Jiangxi, Suichuan County, Dabali, 1400 m, 21 November 1991, Q. Hu & D. H. Hu 032 (holotype SAUT, not seen, isotype Herbarium of Ji’an Forestry Institution, not seen).
Rhizomes amphipodial, internodes terete, 2–2.5 cm long, ca. 2.5 mm in diam. Culms 1.2–2 m tall, up to 8 mm in diam.; internodes terete, 8–24 cm long, green, not powdery, glabrous; wall thick, cavity with woolly or irregularly lamellate pith; supranodal ridge flat, remains of sheath base persistent, sheath scar pubescent or glabrous. Culm buds narrowly ovate. Branches intravaginal, 2–4 at each mid-culm node, base attached to culm. Culm leaf sheaths gradually deciduous or rather persistent, 1/2 to 4/7 as long as internodes, thickly papery, glabrous or sometimes sparsely brown appressed hispidulous, margins ciliolate; auricles absent; oral setae 5–11, lateral 1–4 curved and downward, others straight forward, 6–9 mm long, fragile, base usually adnate; ligule short, less than 0.5 mm, unevenly laciniate, glabrous; blade erect, amplexicaul, striate, broadly ovate-lanceolate, usually longer than sheath, both surfaces glabrous, margins ciliolate, apex acuminate. Foliage leaves 1 to 4 per ultimate branch; sheath 2–4 cm long, upper half more or less white-pilose abaxially, margins ciliolate, glabrescent; outer ligule ca. 0.5 mm long, margin white-pilose; auricles obscure; oral setae present, to 1.4 cm long; inner ligule short, 0.3–1.5 mm; pseudopetiole 1.5–3 mm long, slightly pilose adaxially, glabrous abaxially; blade lanceolate or narrowly lanceolate, 8–24 × 0.9–2 cm, slightly pilose at base adaxially, hispidulous abaxially, glabrescent, base cuneate, margins serrulate, apex acuminate; lateral veins 4–5 pairs, veinlets conspicuous. The unit of inflorescence of the synflorescence 3–9 cm long; main axis glabrous, flattened on the branching side, basal internode 0.8–1.8 cm long. Paracladia 2–4, 0.4–1 cm long, robust, close to the axis, puberulent or appressed-pubescent at the apex, base without a pulvinus. Spikelets 1.6–2 cm long, stramineous; developed (fertile) florets 1–3, uppermost one rudimentary; rachilla segments thickened upwards, 3–4 mm long, glabrous except the upper part white-tomentose; glumes 2, the lower one lanceolate to narrowly lanceolate, 7–10 mm long, glabrous at lower part, pubescent towards the apex, apex acuminate; the upper one with the same shape and indumentum as the lower one, 7–12 mm long; callus bearded with white- or grey-tomentose hairs; lemmas ovate, the lowest one 10–12 mm long, densely adpressed-pubescent abaxially, 9-veined, apex acuminate-mucronate; palea 7–8 mm long, apex obtuse, glabrous except the ciliate and strongly curved keels; lodicules 3, ca. 2 mm long, anterior 2 oblong-obovate, posterior 1 spatulate or obovate, rounded at apex, lower part brown-nerved, upper part hyaline and minutely ciliate; anthers 3, pale yellow, 5 mm long; ripe ovary 2 mm long, brownish when dry; styles 2, persistent, ca. 1 mm long, base slightly connate, stigmas very thin, plumose, ca. 3 mm long. Fruit unknown. Description of inflorescence follows
Culm shoots produced in April to July, flowering in May.
This species is distributed in Hunan, Jiangxi and Guangdong, China. It grows under evergreen broadleaved forests at an elevation from 1100–1600 m.
以礼竹 (pinyin: yĭ lĭ zhú).
Kengiochloa pubiflora: China. Guangdong: Ruyuan County, Tianjingshan, 4 May 1978, Z. P. Wang & S. T. Liu 780047 (N019022073, N019022074, N019022075, N019022076); Shixing County, Longtou Moutain, elev. 1131 m, 25 April 2021, Z. Y. Cai & X. H. Ye czy-146 (IBSC); Xinyi City, Mianbeiding, 20 April 2020, N. H. Xia, Y. H. Tong, J. B. Ni, S. J. Zeng & B. M. Wang XNH-63 (IBSC). Hunan: Yizhang County, Mang Mountain, elev. 1600 m, 4 July 1964, B. M. Yang 026501 (N019022077). Jiangxi: Suichuan County, Dabali, 22 April 2022, C. Long BH-148 (IBSC); ibid. 13 November 2022, C. Long s.n. (IBSC). Indocalamus pallidiflorus: CHINA. Guangdong: Longmen County, Nankun Mountain, 12 April 1932, W. T. Tsang 20216 (SYS00095376, US00065467 (image), US00312706 (image), US00312707 (image)); ibid., 18 April 2018, X. R. Zheng, J. B. Ni & Y. Y. Zhang zxr-145 (IBSC). Indocalamus sinicus: CHINA. Hongkong: hill sides, C. Wright s.n. (K00092161 (image)); without precise locality, Hance s.n. (K00092162 (image), K00092163 (image)).
We are grateful to Dr. Si-Jin Zeng, Mr. Bing-Mou Wang, Mr. Yuan-Qiu Li, Ms. Xue-He Ye and Mr Chuan Long for help during field trips. Mr. Xi-Rong Zheng is thanked for providing the photo of Indocalamus sinicus. This work was supported by the Natural Science Foundation of Guangdong Province (no. 2114050002139) and National Natural Science Foundation of China (grant no. 32270227).