1. Introduction

Melocalamus Benth. is a genus of the tribe Bambuseae (i.e., the tropical woody bamboos). The genus was first proposed by Bentham (1881) without descriptions and was validated in Bentham (1883). It had been long treated as a monospecific genus with the type species, Melocalamus compactiflorus (Kurz) Benth. (Gamble, 1896). A hundred years later, the second species (Melocalamus elevatissimus Hsueh & T.P. Yi) was described from Tibet (Xizang) (Yi, 1983). To date, about 15 species and one variety in Melocalamus have been described, all of which are distributed in Southeast Asia, from northeastern India, Bangladesh, Myanmar, to Thailand, Laos, Vietnam and South China (Ohrnberger, 1999; Guo and Li, 2001; Li et al., 2006; Nguyen and Tran, 2010; Vorontsova et al., 2016; Zhou et al., 2017; Qin et al., 2019).

Species in Melocalamus are characterized by having slender, flexuose and nearly solid culms, several to many branches, with a dominant branch that is occasionally about as thick as and can replace the main culm. Melocalamus have slightly prominent nodes with a ring of white or light yellow-brown powder and/or tomenta above and below the sheath-scales; pseudospikelets with 2-florets; two ovate and glabrous glumes; 2-keeled palea equal to or slightly longer than lemma; three lodicules; a berry-like caryopsis; and fleshy pericarp. There were two species of Melocalamus (i.e., Melocalamus arrectus T.P. Yi and M. elevatissimus) recorded in the Flora Reipublicae Popularis Sinicae (FRPS hereafter) (Keng and Wang, 1996). In contrast, the Flora of China (FOC hereafter) contains four Melocalamus species, i.e., M. arrectus, M. compactiflorus, M. elevatissimus and M. scandens Hsueh & C.M. Hui, as well as M. compactiflorus var. fimbriatus (Hsueh & C.M. Hui) D.Z. Li & Z.H. Guo (Li et al., 2006). However, the typification for M. compactiflorus and its distribution in China was contentious. Neither Kurz nor Bentham specified the type specimen for M. compactiflorus, while Gamble (1896) provided a complete illustration with dissections of florets and fruit for this species on the basis of Kurz's specimens collected in Myanmar and his figure in Bamboo and its use (Kurz, 1876). Hui and Hsueh (1992) firstly recorded this species in China based on the specimens Hsueh 1188, 1186 and Li De-Zhu 84005, 85021, but Guo and Li (2001) identified Hsueh 1188 and 1186 to be M. arrectus instead of M. compactiflorus. After the publication of the FOC bamboo accounts, two new combinations, i.e., Melocalamus yunnanensis (T.H. Wen) T.P. Yi (Yi et al., 2007; Zhang et al., 2016) and M. cordatus (T.H. Wen & Q.H. Dai) D.Z. Li & M.Y. Zhou (Zhou et al., 2017) were recorded in China.

There are several genera of tropical woody bamboos with climbing or scrambling culms in China, including Dinochloa Buse, Holttumochloa K.M. Wong, Neomicrocalamus Keng f. and some species of Dendrocalamus Nees, as well as other species of Cephalostachyum Munro and Schizostachyum Nees (Zhou et al., 2022). Among these genera, species of Dinochloa resemble those of Melocalamus in vegetative characters, such as having slender, flexuose and sometimes solid culms, and several to many branches, with a dominant branch that occasionally can replace the main culm. However, they can be distinguished from those of Melocalamus by their spiral growth habit with zigzag culms, and rough bases of the culm leaves. Furthermore, Dinochloa produce small one-floret pseudospikelets, bearing 2–3 glumes with an obtuse-mucronate apex; mucronate or obtuse lemmas; paleas that are not keeled when present; and lodicules that are usually absent or rarely present. Dinochloa has globose or sub-globose fleshy fruit with a thin pericarp (Dransfield, 1981; Ervianti et al., 2019). There are ca. 46 species of Dinochloa in Southeast Asia, from northeastern India, Bangladesh, and to the Indo-China Peninsula, Indonesia (east to Sulawesi) and the Philippines.

McClure (1940) published three Dinochloa species from Hainan, China based on vegetative specimens, i.e., Dinochloa orenuda McClure, Dinochloa puberula McClure, and Dinochloa utilis McClure. These species were not included in FRPS or in FOC because of their uncertain identity. However, some authors (Guangdong Institute of Botany, 1977; Ohrnberger, 1999; Vorontsova et al., 2016; Ervianti et al., 2019) have still treated these as species in Dinochloa.

Molecular data have been used to resolve the phylogenetic relationships among Southeast Asian climbing bamboos (e.g., Dinochloa, Holttumochloa, Kinabaluchloa K.M. Wong, Maclurochloa K.M. Wong, Soejatmia K.M. Wong and Sphaerobambos S. Dransf.) and the Bambusa Schreber complex, which placed the Dinochloa-Sphaerobambos group at the most basal position in the phylogenetic tree (Goh et al., 2010). However, this study did not sample species of Melocalamus. Plastid data from paleotropical woody bamboos have indicated that species of Dinochloa belongs to the DGMNS (Dinochloa-Greslania-Mullerochloa-Neololeba-Sphaerobambos) assemblage, whereas D. puberula, and D. utilis from Hainan, as well as species of Melocalamus, belong to the BDG (Bambusa-Dendrocalamus-Gigantochloa) complex in the core Bambusinae clade (Zhou et al., 2017). It has also been suggested that D. puberula and D. utilis may be of hybrid origin among Dinochloa, Melocalamus and Bambusa; however, the relationships of the BDG complex have not been well resolved by plastid data.

More recently, Guo et al. (2019, 2021) and Ye et al. (2019) demonstrated that ddRAD-seq data can be used to address phylogenetic issues of bamboos, including those with complex evolutionary history. Liu et al. (2020b) revealed that Melocalamus was monophyletic by using ddRAD-seq data together with support from morphological evidence. In this study, we used morphological and molecular phylogenetic analyses to determine the identity of three doubtful Dinochloa species from Hainan, China. In addition, based on the molecular phylogeny and morphology, an enumeration of species of Melocalamus in China is provided.

2. Materials and methods 2.1. Morphological observation

Morphological data were obtained during fieldwork and based on the analysis of specimens available at herbaria of South China Agricultural University (CANT), Guangxi Institute of Botany, Chinese Academy of Sciences (IBK), Royal Botanical Gardens Kew (K), Kunming Institute of Botany, Chinese Academy of Sciences (KUN), Nanjing University (N), Forestry School of Sichuan Province (SIFC), Southwest Forestry University (SWFC), Sun Yat-Sen University (SYS) and United States National Herbarium at the Smithsonian Institution (US).

2.2. Molecular analyses 2.2.1. Taxon sampling

A total of 43 individuals were sampled, including eight taxa of Melocalamus, 11 species under Dinochloa (17 individuals, including the three doubtful species from Hainan), four species of Bambusa, six species of Dendrocalamus, and four species of Gigantochloa Kurz ex Munro. Outgroup taxa for this analysis included four species of Melocanninae, i.e., Schizostachyum diaoluoshanense N.H. Xia, L.L. Zhang & R.S. Lin, S. pseudolima McClure, S. hainanense Merrill ex McClure and Cephalostachyum sp. Details of the taxon sampling, including voucher information and geographical origin, are provided in Table S1. Fresh leaves were collected for all samples and then rapidly dried in silica gel. Voucher specimens were deposited at KUN.

2.2.2. DNA extraction, library preparation and data assembly

Total DNA was extracted with a modified cetyltrimethylammonium bromide (CTAB) method (Doyle and Doyle, 1987). Only DNA of high concentration (Qubit values ≥ 50 ng/μL) was selected for library construction. For the ddRAD-seq library preparation, we followed the method modified by Yang et al. (2016). The library was diluted to 10 nM and sequenced on an Illumina HiSeq X Ten System (San Diego, CA, USA) using 150 bp pair reads, generating ca. 2 GB data per sample. To identify single nucleotide polymorphism (SNP) sites for phylogenetic reconstruction, de novo clustering was performed on the retained reads using Stacks-1.41 (Julian et al., 2011; Catchen et al., 2013). Parameter settings followed Liu et al. (2020b).

2.2.3. Phylogenomic analyses

For each assembled data set, gene trees were constructed using RAxML-HPC BlackBox (8.2.12) on the Cyberinfrastructure for Phylogenetic Research Science (CIPRES) Gateway (http://www.phylo.org/), applying GTRGAMMA + I model and 1000 bootstrap replicates.

2.2.4. Network analysis

To account for potential conflicting signals within the investigated taxa, we chose the most stable topology matrices from ddRAD-seq and used network analysis on all taxa. SplitsTree v.4 was used with the Neighbor-Net algorithm and uncorrected P-distances (Huson and Bryant, 2006).

3. Results 3.1. Morphological comparison

Species in Melocalamus are similar to those of Dinochloa in some vegetative characters. Both have slender, flexuose and sometimes solid culms, and several to many branches, with the dominant branches sometimes about as thick as and replacing the main culm. We found other characters that provide useful information for identification in the field. Taxa in Dinochloa have a spiral growth habit and zigzag culms, and the bases of culm leaves are usually rough; in contrast, species in Melocalamus are not spiral and do not have zigzag culms (see Fig. 1a, M1: the habit of M. arrectus; D1: the habit of Dinochloa aff. scabrida S. Dransf.). Melocalamus have a ring of white or light yellow-brown powder and/or tomenta above and below the nodes, whereas Dinochloa do not (see Fig. 1a, M2: nodes of Melocalamus orenudus; D2: nodes of Dinochloa malayana S. Dransf.).

Our comparison of the three species from Hainan with the type species of Dinochloa and Melocalamus indicated that the vegetative characters of the three species resemble Melocalamus rather than Dinochloa, despite the lack of inflorescence of the three species. Culms of the three species are not spiral and zigzag, and all three species have a ring of white or yellow-brown powder and/or tomenta above and below the nodes. A morphological comparison of the three doubtful species with species of Dinochloa and Melocalamus is provided in Table 2.

In Melocalamus, species were easily distinguished according to the characters of culm leaf and leaf sheaths. The key morphological characters among species of Melocalamus are presented in Fig. 3.

3.2. Phylogeny with ddRAD-seq data

After filtering ddRAD-seq Illumina raw reads, we obtained high quality sequencing reads for each sample, with approximately 90% of base pairs having quality scores of 30 or above (Q30, sequencing base calls with an error rate of < 0.1%). We generated five SNPs matrices (-p = 20, 25, 30, 35, 40 separately) after the de novo assembly using Stacks. The total length of SNP data sets ranged from 3290 bp to 61, 516 bp except for -p = 40 (with 261 SNPs that lacked effective information).

Maximum Likelihood phylogenetic analyses of four SNPs data sets resulted in two different topologies for the five genera. The topologies of three trees (-p = 20, 25, 30) showed the same relationship between the five genera with almost 100% support (Fig. 1b); one topology (-p = 35), which had lower support, showed a different relationship among Dendrocalamus and Gigantochloa compared with other three topologies (Fig. 1c). The well-resolved phylogenetic trees inferred from the three different SNPs data sets were largely congruent with one another. We selected the phylogenetic tree derived from the -p = 25 data set for subsequent analysis (Fig. 1a).

The phylogenetic tree was divided into three clades, roughly corresponding to Dinochloa, Melocalamus, and a clade of the other three genera (Bambusa, Dendrocalamus, Gigantochloa), i.e., the BDG clade. Melocalamus and Dinochloa were each resolved as monophyletic with 100% bootstrap support. Melocalamus was retrieved as sister to the BDG clade. The three doubtful species from Hainan were associated with the species of Melocalamus with high support (MLBS: 100%). D. utilis was close to the four individuals of D. orenuda, whereas D. puberula was sister to M. yunnanensis.

3.3. Network results

The neighbor-net network constructed from the SNPs (-p = 25) data set revealed a splitting pattern similar to the phylogenetic topology (Fig. 2). The results revealed the three species from Hainan, China were nested within Melocalamus and showed closer relationships with the clade that included M. compactiflorus (the type species of Melocalamus). Species of Melocalamus were separated into two clades and no obvious conflicting signals were found. Species in Dinochloa were clearly separated from Melocalamus.

4. Discussion 4.1. Molecular and morphological evidence supports the placement of the three doubtful species in Melocalamus

Our molecular results indicate the three species from Hainan previously placed in Dinochloa are clustered with the species of Melocalamus (Fig. 1). Our ddRAD-seq data produced a well-resolved clade that confirms Melocalamus is a monophyletic genus (Liu et al., 2020b). This result reinforces the same conclusion previously inferred from nuclear markers such as ITS and GBSSI (Yang et al., 2008). Morphologically, the three doubtful species from Hainan have slender culms, several to many branches, with a dominant branch that occasionally can be about as thick as and replaces the main culm. These species also have nodes with a ring of white or light yellow-brown powder and/or tomenta above and below. All of these characters are similar to Melocalamus rather than Dinochloa (refer to Fig. 3 for the diagnostic characteristics for all recognized species of Melocalamus in China). Network analysis also confirmed that these three species are clearly separate from Dinochloa (Fig. 2). As climbing bamboos, they can be easily distinguished from the genera Bambusa, Dendrocalamus and Gigantochloa. However, previous studies based on plastome phylogeny indicated that species of Melocalamus nest within genera Bambusa, Dendrocalamus and Gigantochloa (Goh et al., 2010; Zhou et al., 2017; Liu et al., 2020b), which implies that hybridization was a frequent occurrence among these genera. We infer that the incongruence between nuclear and plastid data may also be caused by chloroplast capture events which are known to have commonly occurred in temperate bamboos (Yang et al., 2013), Saxifragaceae (Liu et al., 2020c), Salicaceae (Liu et al., 2016) and Fagales (Liu et al., 2020a; Yang et al., 2021). Here, no clear evidence is available to support hybridization; nevertheless, we recommend that future studies address this issue by examining the population genetics of these species.

Another climbing bamboo genus in tropical Asia, Maclurochloa, is similar to Melocalamus and Dinochloa in some vegetative characters, such as having clambering-scrambling culms, and several to many branches, with a dominant branch occasionally about as thick as and replacing the main culm. However, the non-fleshy fruit of Maclurochloa is a noticeable character that was used to distinguished the genus from Dinochloa and Melocalamus. As no flowering material of the three doubtful species from Hainan is available, such material would be useful for further confirmation. In addition, species of Maclurochloa were not included in our ddRAD-seq data due to poor DNA quality obtained from material of specimens. However, one study based on a partial gene showed that Maclurochloa montana (Ridley) K.M. Wong is not closely related to Melocalamus but to Soejatmia ridleyi (Gamble) K.M. Wong, with M. montana and S. ridleyi grouped in one clade with high support (Qin et al., 2019). A study based on plastid loci indicated that Melocalamus is not monophyletic, and placed M. montana at the basal position of the BDG complex, with D. utilis and D. puberula clustered with species of Bambusa (Zhou et al., 2017). The discrepancies between these studies suggest that nuclear data from Maclurochloa are needed to clarify the relationships of climbing bamboos in Southeast Asia.

4.2. Geographic distribution of Melocalamus

To date, there are about 15 species of Melocalamus globally and most are distributed in Southeast Asia, from Southwest China to Vietnam (Vorontsova et al., 2016, Table 1), with the type species M. compactiflorus widespread in Thailand, Myanmar, Laos, South China and northeastern India. Species of Dinochloa are native to Malaysia, Indonesia and Philippines, with five species recorded in northeastern India (Assam, Manipurand, Andamans) and Bangladesh (Table 1). A distribution map for both Dinochloa and Melocalamus (Fig. 1a) was made according to the available specimens and literature (Ohrnberger, 1999; Nguyen and Tran, 2010; Vorontsova et al., 2016; Zhou et al., 2017; Ervianti et al., 2019; Qin et al., 2019). This map shows that the distribution range of Dinochloa is more southward and there is a little overlap between the distributions of Dinochloa and Melocalamus. The three species from Hainan were found within the distribution range of Melocalamus. Based on the present results, we confirm that there has been no recognized Dinochloa species in China yet. However, bamboo surveys in border regions with Laos and northeastern India have been limited. Greater understanding of Melocalamus and Dinochloa can be gained by further field surveys along with molecular investigations.

4.3. Identification key to species of Melocalamus in China

A key to the nine currently known species and one variety of Melocalamus in China is provided on the basis of vegetative morphology.

1. Culm leaf blades erect…………………………………………… 2.

1. Culm leaf blades reflexed………...……………………………… 5.

2. Culm leaf auricles absent or inconspicuous……………………………………………………………… M. elevatissimus

2. Culm leaf auricles conspicuous………………………………… 3.

3. Culm leaves apically oblique, asymmetrical…………………………………………………………………… M. scandens

3. Culm leaves apically truncate, symmetrical……………………. 4.

4. Culm leaf auricles and leaf sheath auricles reflexed, margin with long white fimbriate, ligule apically fringed, easily falling………………………………………………. M. cordatus

4. Culm leaf auricles erect and leaf sheaths auricles small, ligule small, oral setae absent to several………………………………………………………………………… M. arrectus

5. Culm leaf auricles conspicuous…………………………………………………………………………… 6.

5. Culm leaf auricles absent or inconspicuous…………………. 8.

6. Culm leaf auricles narrow, extending upwards………………………………………………………… M. utilis

6. Culm leaf auricles reflexed……………………………………… 7.

7. Culm leaves initially appressed brown or dark-brown pubescent and then glabrous abaxially, auricles brown, wrinkled; ligule apex wide arched.…………………………………….. M. puberulus

7. Culm leaves smooth or with white appressed hairs, auricle margins with long bristles, ligule absent or small…………………………………………… M. compactiflorus

8. Culm leaf ligules fimbriate…………………………………………………………… M. compactiflorus var. fimbriatus

8. Culm leaf ligules inconspicuous………………………………... 9.

9. Culm leaves with brown hairs, scabrous, each side of apex conspicuously protruding……………………… M. yunnanensis

9. Culm leaves with few white, soft hairs, apex flat ………………………………………………… M. orenudus

5. Taxonomic treatment

Based on the morphological, molecular and biogeographical evidence, we here propose three new combinations and enumerate all known species of Melocalamus in China. As a result, a total of eighteen species of Melocalamus are recognized, nine of which are distributed in South and Southwest China.

1. Melocalamus orenudus (McClure) D.Z. Li & J.X. Liu, comb. nov.

无耳梨籐竹(Wu Er Li Teng Zhu) Figs. 3 and 4.

Basionym: Dinochloa orenuda McClure in Lingnan Univ. Sci. Bull. 9: 18, 1940.

Type: CHINA. Hainan: Ling Shui District, Chim Shan, Fan Maan Ts'uen and vicinity, 3–20 May 1932, H. Fung 20230 [holotype, specimens was recorded in SYS with Catalog No.: 21373 and found in US! (US Catalog No.: 2802829 Barcode: 00065462)].

Description: Rhizomes pachymorph, short necked; culms slender, scandent, 9–20 m long, 2–4 cm in diameter, wall ca. 5 mm thick; nodes slightly prominent, each node with a ring of white or light yellow-brown powder and tomenta above and below, internodes initially with white pubescence. Branches several to many, occasionally with a dominant branch replacing main culm. Culm leaves yellow-green when young, shorter than internode, appressed white pubescent abaxially, apex truncate, margins glabrous; blades lanceolate, recurved, more or less cordate at the base, margins glabrous; auricles and oral setae absent; ligules 1–4 mm tall, usually without bristles, entire or lightly toothed. Foliage leaves 7–9 per ultimate branch; sheaths slightly pubescent and white powdery which are easily deciduous, margins glabrous; ligules 1–2 mm; auricles absent; blades lanceolate to oblong-lanceolate, rounded at the base, 7–18 × 1.2–3 cm, glabrous or white pubescent abaxially, margins coarse.

Inflorescence unknown.

Local name (Cantonese): T'ang Chuk (籐竹).

Additional specimens examined: —CHINA. Hainan: Ling Shui District, Chim Shan, Fan Maan Ts'uen and vicinity, 4–20 May 1932, F.A. McClure 20087 (SYS); Bao Ting, Ganzhaling Nature Reserve, 22 Aug 2018, Liu Jing-Xia & Xu Zu-Chang Liujx18063 (KUN); Ling Shui, Diaoluo Mountain National Nature Reserve, 24 Aug 2018 Liu Jing-Xia & Xu Zu-Chang Liujx18076 (KUN); San Ya, Tian Ya, Ming Shan, 26 Aug 2018, Liu Jing-Xia & Xu Zu-Chang Liujx18079, Liujx18081 (KUN); San Ya, Tian Ya area, Ya Lin, 27 Aug 2018, Liu Jing-Xia & Xu Zu-Chang Liujx18084, Liujx18088 (KUN).

2. Melocalamus puberulus (McClure) D.Z. Li & J.X. Liu, comb. nov.

毛梨籐竹(Mao Li Teng Zhu) Figs. 3 and 5.

Basionym: Dinochloa puberula McClure in Lingnan Univ. Sci. Bull. 9: 19, 1940. ≡ Neohouzera puberula (McClure) Wen in J. Bamboo Res. 10(1): 14, 1991. (misspelled as "puberala").

Type: CHINA: Hainan, Lin-kaoi (Lam Ko) District, enroute FaanLun to Naam Fung, 28 Aug 1929, McClure 837 (L. U. 18370) [holotype, specimens recorded in SYS but found in US! (US Catalog No.: 2802830, Barcode: 00065463)].

Description: Rhizomes pachymorph, short necked; culms slender, scandent, 10–30 m long, 2–3.5 cm in diameter; wall ca. 4 mm thick; nodes prominent, a ring of white-yellow tomenta present above and below the nodes, internodes initially with white pubescence. Branches several to many with one dominant and sometimes as thick as and replacing main culm. Culm leaves initially appressed brown or dark-brown pubescent and then glabrous abaxially, margins glabrous, gray–green when young; blades lanceolate, recurved, cordate at the base, margins glabrous; auricles conspicuous, brown, reflexed, wrinkled, oral setae radiated (1.5–2.5 cm long); ligules 1.5–4 mm tall, apex wide arched, fimbriate. Foliage leaves ca. 13 per ultimate branch; sheaths slightly pubescent and white powdery, easily deciduous, margins glabrous; auricles conspicuous, oral setae radiated (1–1.5 cm); ligules 1–2 mm tall, fimbriate, apex truncate; blades lanceolate to oblong-lanceolate, rounded at the base, 5–25 × 1.2–4 cm, glabrous or back with white pubescence, margins coarse. Inflorescence unknown.

Additional specimen examined: —CHINA. Hainan: Taam Chau District, Sha Bao Shan, 24 Apr 1929, Tsang, Tang & Fung 17 (L. U. 17548) (SYS); Taam Chau District, Nodoa and Naam Fung, 10–11 Jul 1929, H. Fung 866 (L. U. 18389) (SYS); Lai (Loi) area, Hung Mo Shan and vicinity, 7 May 1929, Tsang, Tang & Fung 114 (L. U. 17645) (SYS); Cang Jiang, Bawangling Nature Reserve, 12 Jul 2017, Zhou Meng-Yuan et al. zmy041 (KUN).

3. Melocalamus utilis (McClure) D.Z. Li & J.X. Liu, comb. nov.

陵水梨籐竹(Ling Shui Li Teng Zhu) Figs. 3 and 6.

Basionym: Dinochloa utilis McClure in Lingnan Univ. Sci. Bull. 9: 20, 1940.

Type: CHINA: Hainan, Ling Shui District, Chim Shan, Fan Maan Ts'uen and vicinity, 4–20 May 1932, McClure 20136 [holotype, specimens recorded in SYS, but found in US (US Catalog No.: 2802831, Barcode: 00065464); isotype, specimens recorded in SYS but found in US! (US Catalog No.: 2767635, Barcode: 00036336; No.: 2767636, Barcode: 00036337)].

Description: Rhizomes pachymorph, short necked; culms slender, scandent, ca. 10 m long, 4–5 cm in diameter; wall ca. 5 mm thick; nodes slightly prominent, a ring of white-yellow tomenta present above and below the nodes, internodes initially with several white spiny hairs; sheath scars prominent. Branch many, occasionally with a dominant branch replacing main culm. Culm leaves with appressed light-yellow or light-brown spiny hairs abaxially, margins glabrous, yellow-green but red at the margin and basal part when young; blades lanceolate, recurved, cordate at the base, margins glabrous; auricles narrow, extending upwards, oral setae absent; ligules ca.1 mm tall, concave, without bristles, entire or lightly toothed. Foliage leaf sheaths slightly striped, glabrous; auricles narrow, extending upwards with several bristles; ligules 1 mm tall, entire; blades lanceolate, rounded at the base, 7–13 × 1–2 cm, glabrous, margins coarse.

Inflorescence unknown.

Local name (Cantonese): Tang Chuk (籐竹); Loi: Soo; Too.

Additional specimen examined: —CHINA. Hainan: Lai area, Hung Mo Shan and vicinity, 16 May 1929, Tsang, Tang & Fung 17725 (SYS); Ling Shui, Diaoluo Mountain National Nature Reserve, 10 Jul 2017, Zhou Meng-Yuan et al. zmy034 (KUN).

4. Melocalamus arrectus T.P. Yi

澜沧梨籐竹(Lan Cang Li Teng Zhu) Figs. 3 and 7.

M. arrectus T.P. Yi in Acta Bot. Yunnan. 10 (4): 440. f. 3. 1988.

Dinochloa bambusoides Q.H. Dai in Bamboo Spec. & Cult. Guangxi, pp. 9. f. 3. 1987. nom. nud.

Type: CHINA: Yunnan, Lancang, secondary forests, alt. 1900 m, 20 Feb 1987, Yi Tong-Pei 87019 (holotype, SCFI).

Additional specimen examined: —CHINA. Yunnan: Jiangcheng, Menglie, Niuluohe, 10 Aug 2012, Zhang Yu-Xiao et al. 12143, 12150 (KUN); Cangyuan, Nangun River National Park, alt. 1500 m, 10 Aug 1986, Hui Cao-Mao 0062 (SWFC); ibid., alt. 1738 m, 16 Aug 2012, Zhang Yu-Xiao et al. 12187 (KUN); ibid., 22 Apr 2016, Liu Jing-Xia & Guo Cen Liujx16029 (KUN); ibid., Nanla, Hui Cao-Mao 0076 (SWFC); ibid., Banhong, alt. 1000 m, 18 Dec 1986, Xue Jia-Rong 86011 (SWFC); ibid., Banhong to Mengding Road, alt. 1495 m, 16 Aug 2012, Zhang Yu-Xiao et al. 12190 (KUN); ibid., Banhong, Hongwei Bridge, alt. 640 m, 25 Aug 2019, Guo Cen et al. GC19009 (KUN); Shuangjiang, alt. 1400 m, 20 Apr 1990, Hui Cao-Mao 90418 (SWFC); Ruili, 5 Sep 1999, Hsueh 1169 (SWFC); Hekou, Nanxi, alt. 120 m, 9 Nov 1985, Li De-Zhu 85291 (SWFC).

5. Melocalamus compactiflorus (Kurz) Benth.

梨籐竹(Li Teng Zhu) Figs. 3 and 8.

M. compactiflorus (Kurz) Benth. in Gen. Pl. 3(2): 1212, 1883.

Basionym: Pseudostachyum compactiflorum Kurz, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 42(4): 252, 1874.

Dinochloa compactiflora (Kurz) McClure in Bull. Misc. Inform. Kew. 1936: 253, 1936.

Type: MYANMAR: Pegu, Karen Hills, Kurz S. 3183 [lecto-designated here: BM!, Barcode: BM000959270; isolecto-: K!, Barcodes: K000912020, K000912021].

Additional specimen examined: — CHINA. Guangxi: Pingxiang, Nahuai Forest Farm, alt. 400 m, 30 Nov 1985, Hsueh 1011 (SWFC); — THAILAND: Phu Soi Dao National Park, 7 Dec 2019, Zhang Yu-Xiao et al. 19064 (KUN).

Note: Here we designate Kurz 3183 at BM as the lectotype of Melocalamus compactiflorus which fits well with the protologue of Kurz. The distribution of M. compactiflorus in China was previously controversial (Guo and Li, 2001; Hui and Hsueh, 1992). We carefully checked the specimens in SWFC cited in Hui and Hsueh (1992), and agree with Guo and Li (2001) that M. compactiflorus in Yunnan was misidentified. We identified only specimens of Hsueh 1011, which were collected from Guangxi, to be M. compactiflorus; other specimens cited in Hui and Hsueh (1992) and Guo and Li (2001) were different, probably belonging to undescribed species. We recommend that more field surveys be undertaken to clarify the identity of those dubious specimens.

5a. M. compactiflorus var. fimbriatus (Hsueh & C.M. Hui) D.Z. Li & Z.H. Guo

流苏梨籐竹(Liu Su Li Teng Zhu) Figs. 3 and 9.

M. compactiflorus var. fimbriatus (Hsueh & C. M. Hui) D. Z. Li & Z. H. Guo in Acta Bot. Yunnan. 23(2): 178, pl. 1. 2001.

Basionym: Melocalamus fimbriatus Hsueh & C. M. Hui (in Acta Phytotax. Sin. 30(2): 167, pl. 1, f. 5–9. 1992.)

Type: CHINA: Yunnan, Menglian to Lancang, alt. 1100 m, 30 Sep 1985, Li De-Zhu 85246 (holotype, SWFC!, Catalog No.: 0065827).

Additional specimen examined: —CHINA. Yunnan: Yingjiang, Muwen, alt. 1100 m, 29 Apr 1992, Zhang Wei-Ping 8400621 (SWFC); ibid., Sudian, Pishi, alt. 1590 m, 8 Aug 1984, Li De-Zhu 84035 (SWFC); ibid., the road side of Pishi to Lumian, alt. 1690 m, 8 Aug 1984, Li De-zhu 84034 (SWFC); Jinghong, Jinuo, 12 Nov 1985, Hui Cao-Mao 85310 (SWFC); Menghai, Daluo, alt. 1700 m, 1 Sep 1986, Du Fan 86046 (SWFC); ibid., Bulangshan, Lagan, alt. 1500 m, 14 Sep 1986, Du Fan 86069 (SWFC); ibid., alt. 1650 m, 14 Sep 1986, Du Fan 86060; ibid., Banchang, alt. 1650 m, 11 Sep 1986, Du Fan 86061, 86062 (SWFC); ibid., Bulang Nature reserves, alt. 1680 m, 10 May 2018, Zhang Yu-Xiao et al. 18011 (KUN); ibid., alt. 1130 m, 21 May 2019, Zhang Yu-Xiao et al. 19002 (KUN); Malipo, Tianbao, alt. 1199 m, 19 Aug 2014, Ye Xia-Ying & Guo Cen YXY149 (KUN).

6. Melocalamus cordatus (T. H. Wen & Dai) D.Z. Li & M.Y. Zhou

糯米竹(Nuo Mi Zhu) Figs. 3 and 10.

M. cordatus (T.H. Wen & Dai) D.Z. Li & M.Y. Zhou in Taxon 66(3): 547, 2017.

Basionym: Neohouzeaua cordata T.H. Wen & Dai in J. Bamboo Res. 10(1): 12, 1991 (misspelled as "coradata").

Type: CHINA. Guangxi: Pingxiang, 7 Nov 1973, Wen Tai-Hui 73115 (holotype, ZJFI).

Additional specimen examined: —CHINA. Guangxi: Longzhou, Daqing Mountain, alt. 815 m, 13 May 2014, Ye Xia-Ying & Guo Ying, YXY022 (KUN).

7. Melocalamus elevatissimus Hsueh & T.P. Yi

西藏梨籐竹(Xi Zang Li Teng Zhu) Figs. 3 and 11.

M. elevatissimus Hsueh & T.P. Yi in J. Bamboo Res. 2(1): 28, f. 1, 1983.

Type: CHINA. Tibet (Xizang), Motuo, Beibeng, Deergong, alt. 940–2000 m, 15 Aug 1977, Yi Tong-Pei 77183 (holotype, SCFI!; isotype, SWFC!, Catalog No.: 0065824).

Additional specimen examined: —CHINA. Tibet (Xizang): Motuo, alt. 1995 m, 15 Jul 2021, Xiahou Zuo-Ying XHZY2021003 (KUN); Yadong, Xiayadong, alt. 1625 m, 16 Jul 2021, Ya Ji-Dong et al. 21CS20510 (KUN).

8. Melocalamus scandens Hsueh & C.M. Hui

大吊竹(Da Diao Zhu) Figs. 3 and 12.

M. scandens Hsueh & C.M. Hui in Acta Phytotax. Sin. 30(2): 166, pl. 1, f. 1–4, 1992.

Type: CHINA. Yunnan: Jiangcheng, Mantan, alt. 1100 m, 1 Apr 1988, Zhao Jian-Wei & Hui Chao-Mao 88027 (holotype, SWFC!, Catalog No.: 0065846).

Additional specimen examined: —CHINA. Yunnan: Jiangcheng, Niuluohe, alt. 770 m, 29 Mar 1988, Zhao Jian-Wei & Zhou De-Sheng 88019 (SWFC); ibid., Mantan, alt. 1022 m, 13 Apr 2016, Liu Jing-Xia & Guo Cen Liujx16005 (KUN).

9. Melocalamus yunnanensis (T.H. Wen) T.P. Yi

高肩梨籐竹(Gao Jian Li Teng Zhu) Figs. 3 and 13.

M. yunnanensis (T.H. Wen) T.P. Yi in J. Sichuan Forest. Sci. Technol. 28(2): 6, 2007.

Basionym: Racemobambos yunnanensis T.H. Wen in J. Bamboo Res. 5(2): 11, 1986.

Neomicrocalamus yunnanensis (T.H. Wen) Ohrnb. in Bamboos World Introd. 4: 19, 1997; Li & Stapleton, Fl. China 22: 57, 2006.

Type: CHINA. Yunnan: Jinping, Mengla, Zhou Wen-Wei 83311 (holotype, ZJFI).

Additional specimen examined: —CHINA. Yunnan: Jinping, Mengla, alt. 500 m, 31 Oct 1985, Zhang Wei-Ping 840319 (SWFC); Jiangcheng, Zhengdong, Manhe, Dajiacao, alt. 860 m, 12 Aug 2012, Zhang Yu-Xiao et al., 12153, 12154 (KUN); Mengla, Bubang, alt. 790 m, 8 Apr 2013, Zhang Yu-Xiao & Xu Yu-Xing 13006 (KUN).

Note: This species was published based on poor, sterile material as a species of Racemobambos and misplaced in Neomicrocalamus by Ohrnberger (1999), which was followed by FOC bamboo accounts. Yi's treatment in Melocalamus was echoed by an earlier molecular study (Yang et al., 2008). Zhang et al. (2016) supplemented a description of its flowering specimens collected in 2012 and 2013, and confirmed its membership in Melocalamus, which was consolidated by more recent molecular studies (Zhou et al., 2017; Liu et al., 2020b).

10. Taxon

Melocalamus gracilis W.T. Lin (Type: Chen Peng-Fei 4726, deposited at CANT!) was described from sterile material from Guangxi (Ningming) (Lin, 1993). However, the name M. gracilis R.B. Majumdar was used by Karthikeyan et al. (1989) for another entity, making M. gracilis W.T. Lin a late homonym, and thus illegimate (Turland et al., 2018). Subsequently, Ohrnberger renamed it as M. ningmingensis (Ohrnberger, 1997, 1999). To date, we have only been able to check the type specimens collected from Guangxi in 1985. No other specimens or further information was available for examination. We were unable to carry out fieldwork on this species, and temporarily treated it as a taxon incertae sedis due to limited information.

Acknowledgements

We thank the staff of the Diaoluo Mountain National Nature Reserve and Ganzhaling Nature Reserve, Hainan, China; the staff of Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Myanmar and Dr. Thammarat Boonthammee and Dr. Dieter Ohrnberger (Thailand) for their kind help in fieldwork. We are grateful to Ms. Wang Jia-Yan from Sun Yat-sen University, Dr. Yao Gang from South China Agricultural University for their help in checking the specimens and Dr. Ye Xia-Ying, Mr. Zuo Zheng-Yu as well as Xiahou Zuo-Ying for providing pictures. We sincerely thank the Molecular Biology Experiment Center, Germplasm Bank of Wild Species for facilitating the laboratory work. We are also indebted to Singapore Botanic Garden and the Research Center for Biology of Indonesian Institute of Sciences for permission to access their collections. The project was supported by the National Natural Science Foundation of China (31670396 and 31800181), Postdoctoral Directional Training Foundation of Yunnan Province, China (E2317482) and the Key R & D program of Yunnan Province, China (202103AC100003).

Author contributions

JXL conducted the fieldwork, lab and phylogenomic work and drafted this paper; ZCX produced the pictures and drafted the taxonomic treatment; YXZ conceived and revised the draft; MYZ revised the draft; DZL conceived and wrote this paper.

Declaration of competing interest

The authors declare no conflicts of interest.

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.pld.2022.07.001.