J. Jpn. Bot. 91(6): 337–344 (2016)

Two New Combinations of Leptopetalum () Based on Molecular Phylogenetic Evidence

a, b b b Akiyo Naiki *, Yoshiteru Komaki , Keiko Mizunashi and Tetsuo Ohi-Toma

aIriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, 870, Uehara, Yaeyama-gun, Okinawa 907-1541 JAPAN; bBotanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1, Hakusan, Bunkyo-ku, Tokyo 112-0001 JAPAN *Corresponding author: [email protected]

(Accepted on October 11, 2016)

As a result of our phylogenetic analysis, two new combinations, Leptopetalum pachyphyllum (Tuyama) Naiki & Ohi-Toma, and L. strigulosum (Bartl. ex DC.) Neupane & N. Wikstr. var. luxurians (Hatus.) Naiki & Ohi-Toma, are proposed for taxa formerly in Hedyotis s.l., which was recently divided into 13 genera recircumscribed on the basis of the phylogenetic and morphological evidences. Leptopetalum pachyphyllum is closely related to L. mexicanum Hook. & Arn., the type of the , and L. grayi (Hook. f.) Hatus., shrub endemic to the Ogasawara Islands, Japan. Leptopetalum strigulosa var. luxurians is nested in the of L. strigulosum.

Key words: Bonin Islands, Hedyotis, Kazan Islands, Leptopetalum pachyphyllum, Leptopetalum strigulosum var. luxurians, Ogasawara Islands, Rubiaceae, Volcano Islands.

Hedyotis L. s.l. (including : W. H. Lewis, Oldenlandia L., and Scleromitrion Rubiaceae) comprises 500–600 species of (Wight & Arn.) Meisn. herbs, subshrubs and shrubs from tropical, The genus Leptopetalum was described in subtropical to warm temperate regions in the 1838 by W. J. Hooker and G. A. Walker-Arnott world (Neupane et al. 2015). Since the genus based on L. mexicanum Hook. & Arn. (Hooker is a highly heterogeneous assembly, many and Walker-Arnott 1830–41). The original separate genera have been recognized. Neupane material was collected from the Ogasawara et al. (2015) accepted the following 13 genera (Bonin) Islands, Japan, but mistakenly supposed based on previous, and their own, detailed to have been collected from Mexico (Fosberg morphological and/or phylogenetic analyses and Sachet 1991, Ohba 2003). For many (Terrell et al. 2005, Groeninckx et al. 2010, years, Leptopetalum was treated as a subgroup Guo et al. 2013, Wikström et al. 2013): Debia of Hedyotis or Oldenlandia, cf. Hedyotis Neupane & N. Wikstr., Dentella J. R. Forst. [unranked] Leptopetalum (Hook. & Arn.) Hook. & G. Forst., Dimetia (Wight & Arn.) Meisn., f., Hedyotis subgenus Leptopetalum (Hook. Edrastima Raf., Exallage Bremek., Hedyotis & Arn.) Fosberg & Sachet, or Oldenlandia s.str., Involucrella (Benth. & Hook. f.) Neupane, sect. Leptopetalum (Hook. & Arn.) K. Schum., Kadua Cham. & Schltdl., Kohautia Cham. & although some Japanese botanists published Schltdl., Leptopetalum Hook. & Arn., Neanotis new species and new combinations under

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Leptopetalum (Hatusima 1936, Hosokawa (Fig. 1)). Regardless of the mistake of the 1938). In Flora of Japan, Yamazaki (1993) citation, the publication by Fosberg and Sachet published Hedyotis subgenus Leptopetalum (1991) can be regarded as a valid one because (Hook. & Arn.) T. Yamaz. as a new rank, but the they designated one of the two ‘type specimens’ name was a later isonym of Hedyotis subgenus by Tuyama (1968) as the type. Leptopetalum (Hook. & Arn.) Fosberg & Sachet. Although Hedyotis pachyphylla is thought Recent phylogenetic studies indicated that to be closely related to the shrub species in two species of Leptopetalum (L. foetidum (G. the Mariana Islands rather than Leptopetalum Forst.) Neupane & N. Wikstr. and L. mexicanum) grayi and L. mexicanum, which are endemic formed a distinct clade together with three small to the Ogasawara (Bonin) Islands (Tuyama annual or perennial herbs of Thecagonum Babu: 1968, Ono and Kobayashi 1985, Fosberg and T. biflorum (L.) Babu, T. pteritum (Blume) Babu Sachet 1991), its phylogenetic relationship and T. strigulosum (Bartl. ex DC.) Terrell & H. has not been investigated. In the present study, Rob, all of which were once treated as species of we investigated the phylogenetic position Hedyotis and Oldenlandia (Wikström et al. 2013, of H. pachyphylla based on the nucleotide Neupane et al. 2015). Neupane et al. (2015) sequences of nuclear ribosomal ITS regions, and recircumscribed Leptopetalum that comprises chloroplast rps16 intron and petB–petD spacer. L. biflorum (L.) Neupane & N. Wikstr., L. Consequently, Leptopetalum pachyphyllum foetidum, L. pteritum (Blume) Neupane & N. (Tuyama ex Fosberg & Sachet) Naiki & Ohi- Wikstr., L. strigulosum (Bartl. ex DC.) Neupane Toma, a new combination, is here published. & N. Wikstr., L. mexicanum Hook. & Arn. (= Leptopetalum strigulosum (Bartl. ex DC.) H. hookeri (K. Schum.) Fosberg), and L. grayi Neupane & N. Wikstr. var. luxurians (Hatus.) (Hook. f.) Hatus., based on their morphological Naiki & Ohi-Toma is also published as a new and phylogenetic evidences. Leptopetalum is combination because the variety was not treated characterized by being glabrous throughout in the newly recircumscribed genus by Neupane and the ovoid or obtusely angulate seeds et al. (2015). appearing pitted due to shallow depressions bordered by thick and sinulate walls (Neupane et Materials and Methods al. 2015). Nucleotide sequences of ITS, rps16 intron, Hedyotis pachyphylla was published in and petB–petD spacer were used for the 1968 by Tuyama from the Volcano (Kazan) present phylogenetic analysis. In addition to Islands, Japan (Tuyama 1968). This publication, Leptopetalum samples with which the three however, was invalid because two specimens regions were analyzed in Guo et al. (2013), were cited as types (‘H. Huzikawa, Aug. 20, Wikström et al. (2013), and Neupane et al. 1930–typus fructus in TI’ and ‘M. Okabe, Oct. (2015), nucleotide sequences of Japanese 22, 1935–typus floris in TI’), contrary to the Leptopetalum and H. pachyphylla were newly Art. 40.1 and 40.2 of the Melbourne Code determined (Appendix 1). Total genomic DNA (McNeill et al. 2012). The name was validly was extracted from silica-gel-dried leaf tissue, published when Fosberg and Sachet (1991: 204) using the modified HEPES-CTAB method designated ‘Okabe in 1935 (TI)’ as the lectotype described by Ohi-Toma et al. (2010). Nucleotide with a direct reference to Tuyama (1968). They sequences were determined using polymerase cited the collection locality as ‘Iwoto’ (Sulphur chain reaction (PCR) and direct bi-directional Island) whereas ‘Okabe in 1935 (TI)’ was sequencing. PCR amplification was conducted actually collected from ‘Kita-Iwoto’ (as ‘San using TaKaRa Ex Taq (TaKaRa Bio, Shiga, Alessandro Island’ on the label of the specimen Japan), at the following cycling conditions: December 2016 The Journal of Japanese Vol. 91 No. 6 339

Fig. 1. Holotype of Hedyotis pachyphylla Tuyama ex Fosberg & Sachet (M. Okabe s.n., TI00044065). denaturation at 96°C for 45 sec, followed by 33 and PIpetB1365F and PIpetD738R for petB– cycles at 96°C for 45 sec, annealing at 50°C for petD (Löhne and Borsch 2005). Amplification 45 sec, extension at 72°C for 1 min, and a final products were purified using illustra ExoProStar extension at 72°C for 10 min. For amplifying (GE Healthcare UK Ltd., Buckinghamshire, and sequencing, we used the following published England, UK). The purified PCR fragments were universal primers: ITS5 and ITS4 (White et al. amplified using the Big Dye Terminator v3.1 1990), F and 2R for rpl16 (Oxelman et al. 1997), Cycle Sequencing Kit (Applied Biosystems, 340 植物研究雑誌 第 91 巻 第 6 号 2016 年 12 月

Fig. 2. Strict consensus tree of 180 most parsimonious trees of Leptopetalum, based on the combined data of nuclear ribosomal ITS regions, and chloroplast rps16 intron and petB– petD spacer. Values above the nodes represent the number of nucleotide changes, and values below the nodes represent bootstrap support.

Foster City, California, USA). Cycle-sequencing basis of the molecular phylogenetic study of reactions were performed using the same Neupane et al. (2015) (Appendix 1). primers for the PCR amplification. Sequencing The nucleotide sequences, including was performed using Applied Biosystems® sequences from GenBank, were manually 3130 Genetic Analyzer. All newly generated aligned and gaps, except the length nucleotide sequences were deposited in the polymorphisms caused by mononucleotide DNA Data Bank of Japan (DDBJ). Two Kadua repeats, were binary coded as a fifth character. species were selected as outgroup taxa on the The incongruence length difference (ILD) December 2016 The Journal of Japanese Botany Vol. 91 No. 6 341 among ITS, rps16, and petB–petD was tested were recognized in Leptopetalum, using a partition-homogeneity test in PAUP* although a few branches were weakly supported. v.4.0a150 (Swofford 2002). A three-way test The clade of L. pteritum in Southeast Asia (BP was run using a heuristic search of 10,000 98%) was the first to branch off in the genus. replicates, with 10 random stepwise additions, Leptopetalum biflorum was not monophyletic tree bisection and reconnection (TBR) branch and was divided into two clades, 1) Nepal and swapping, MulTrees in effect, and no limit of China (BP 47%) and 2) Singapore and Ryukyu MaxTrees limit. Since the test indicated that the in Japan (BP 100%). The shrub species in the three regions were not significantly incongruent, Volcano Islands, Hedyotis pachyphylla (shown their combined sequences were used as a final as Leptopetalum pachyphyllum in Fig. 2), formed matrix. In order to use coded gaps, Maximum a clade with two endemic shrub species in the Parsimony analysis was applied using PAUP*, Ogasawara Islands, L. grayi and L. mexicanum nucleotide substitutions and coded gaps were (BP 100%). Leptopetalum strigulosum and given equal weights, and the tree search Hedyotis strigulosa var. luxurians (shown as was performed using the branch-and-bound L. strigulosum var. luxurians in Fig. 2) were search option with MulTrees in effect. The monophyletic (BP 100%). Relationships among strict consensus tree of the most parsimonious three clades, L. biflorum from Singapore and trees was generated, and substitutions were Japan, the shrub species, and L. strigulosum, reconstructed on the tree using ACCTRAN were unclear due to a polytomy. character optimization. The MP bootstrap support (BS) values were estimated using a Discussion heuristic search of 10,000 replicates, with simple To maintain the monophyly of the genus sequence addition, TBR branch swapping, Leptopetalum, Hedyotis pachyphylla should be Multrees in effect, and a MaxTree limit of 100. treated as a member of the genus Leptopetalum. The species is closely related to L. grayi and L. Results mexicanum. Further analyses on relationships Nucleotide sequences of ITS (627–632 bp), among shrub species in the Ogasawara Islands rps16 (863–894 bp), and petB–petD (996 bp) and Mariana Islands remain to be observed. were determined for 21 samples. In multiple Leptopetalum strigulosm is widely distributed alignment with sequences from GenBank, 5ʹ from Asia, through New Guinea, Malesia, and and 3ʹ ends were arranged in accordance with Micronesia. Yamazaki (1993) treated plants from shorter sequences cited from Genbank. The Kita-Daito-jima Island with stout stem and thick aligned lengths of the three regions are 564 bp leaves as a variety of this species. The present for ITS, 768 bp for rps16, and 903 bp for petB– phylogenetic analysis, showing monophyly of L. petD. Considering the result of the ILD test, strigulosum including this variety, supports the nucleotide sequences of the three regions were treatment of Yamazaki (1983). Consequently a combined (total aligned length of 2,235 bp), and new combination L. strigulosum var. luxurians is nine coded gaps were added to the data matrix. necessary. Thus, the matrix of 2,244 bp was used for the Leptopetalum biflorum has been recognized phylogenetic analysis. Maximum Parsimony as a widespread species distributed throughout analysis resulted in a strict consensus tree from the Indo-Pacific and African tropics (Fosberg and 180 most parsimonious trees with tree lengths of Sachet 1991). The present phylogenetic analysis 257 steps (CI = 0.8210, RC = 0.1790) generated indicated that the species was not monophyletic. with branch lengths (Fig. 2). Yonekura (2012) recognized Hedyotis paniculata In the strict consensus tree, five monophyletic (L.) Lam., which may correspond to the second 342 植物研究雑誌 第 91 巻 第 6 号 2016 年 12 月 clade of L. biflorum from Singapore and Japan study of Kohautia (, Rubiaceae), with as in the present (Fig. 2). the recognition of the new genus Cordylostigma. 59: 1457–1471. Further phylogenetic analyses and taxonomic Guo X., Wang R. J., Simmons M. P., But P. P. H. and Yu J. investigations throughout the distribution range 2013. Phylogeny of the Asian Hedyotis-Oldenlandia are required for the species. complex (Spermacoceae, Rubiaceae): Evidence for high levels of and the parallel evolution of Taxonomic treatment diplophragmous capsules. Molec. Phylogent. Evol. 67: 110–122. Leptopetalum pachyphyllum (Tuyama ex Hatusima S. 1936. Materials for a flora of Micronesia. Fosberg & Sachet) Naiki & Ohi-Toma, comb. Trans. Nat. Hist. Soc. Formos. 26: 217–226. nov. ≡ Hedyotis pachyphylla Tuyama [in J. Jap. Hooker W. J. and Walker-Arnott J. A. 1830–1841. 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Terrell E. E., Robinson H., Wagner W. L. and Lorence D. LC180264*; Chichi-jima Island, Ohi-Toma KBG2016-017 H. 2005. Resurrection of genus Kadua for Hawaiian (TI), LC180223*, LC180244*, LC180265*. Hedyotidinae (Rubiaceae), with emphasis on seed and Leptopetalum mexicanum Hook. & Arn. JAPAN. fruit characters and notes on South Pacific species. Tokyo Pref., Ogasawara Islands, Haha-jima Island, Ohi- Syst. Bot. 30: 18–833. Toma KBG1992-321 (TI), LC180224*, LC180245*, Tuyama T. 1968. A new species of Hedyotis (Rubiaceae) LC180266*; Chichi-jima Island, Ohi-Toma KBG2016-016 from the Volcano Islands. J. Jap. Bot. 43: 401–404. (TI), LC180225*, LC180246, LC180267*. White T. J., Bruns T., Lee S. and Taylor J. W. 1990. Leptopetalum pachyphyllum (Tuyama) Naiki & Ohi- Amplification and direct sequencing of fungal Toma. JAPAN. Tokyo Pref., Volcano Islands, Kitaio- ribosomal RNA genes for phylogenetics. In: Innis M. to Island, Ohi-Toma KBG 2008-106 (TI), LC180226*, A., Gelfand D. H., Sninsky J. J. and White T. J. (eds.), LC180247*, LC180268*; Kitaio-to Island, Ohi-Toma KBG PCR Protocols: A Guide to Methods and Applications, 2008-107 (TI), LC180227*, LC180248*, LC180269*. pp. 315–322. Academic Press, Inc., New York. Leptopetalum pteritum (Blume) Neupane & N. Wikström N., Neupane S., Kårehed J., Motley T. J. and Wikstr. CAMBODIA. Neupane 149 (ODU), KP994273, Bremer B. 2013. Phylogeny of Hedyotis L. (Rubiaceae: KP005821, KR005758. THAILAND. Neupane 163 Spermacoceae): redefining a complex Asian-Pacific (ODU), KP994274, KP005822, KR005759. assemblage. Taxon 62: 357–374. Leptopetalum strigulosum (DC.) Neupane & N. Yamazaki T. 1983. On Hedyotis strigulosa Bartl., H. Wikstr. var. strigulosum. JAPAN. Fukuoka Pref., Itoshima, coreana Levl. and H. biflora(L.) Lamk. J. Jap. Bot. 58: Naiki 7406 (KYO), LC180237*, LC180258*, LC180279*. 281–286 (in Japanese). Kagoshima Pref., Shimokoshiki Island, Takahashi s.n. Yamazaki T. 1993. Hedyotis. In: Iwatsuki K., Yamazaki T., (TI), LC180236*, LC180257*, LC180278*. Okinawa Boufford D. E. and Ohba H. (eds.), Flora of Japan IIIa: Pref., Yonaguni Island, Ohi-Toma KBG2016-030 (TI), 215–218. Kodansha, Tokyo. LC180228*, LC180249*, LC180270; Iriomote Island, Yonekura K. 2012. An Enumeration of the Vascular Plants Toyohara, Naiki 7467 (KYO), LC180229*, LC180250*, of Japan. Hokuryukan, Tokyo (in Japanese). LC180271*; Naiki 7909 (KYO), LC180230*, LC180251*, LC180272*; Ishigaki Island, Kannonzaki, Ito & Yano Appendix 1 s.n. (TI), LC180231*, LC180252*, LC180273*; Ishigaki List of samples used for phylogenetic analysis with Island, Tomino, Ohi-Toma & Naiki 2016070102 (TI), voucher information (geographic origin, collector, voucher LC180232*, LC180253*, LC180274*; Ishigaki Island, number, herbarium) and DNA accession numbers (ITS, Ohama, Ohi-Toma & Naiki 2016070103 (TI), LC180233*, rps16, and petB–petD). The dataset consists of sequences LC180254*, LC180275*; Okinawa Island, Ito & Yano from Wikström et al. (2015) and Guo et al. (2001, 2013), s.n. (TI), LC180234*, LC180255*, LC180276*; Aguni and the newly generated sequences with an asterisk. Island, Ito & Yano s.n. (TI), LC180235*, LC180256*, LC180277*. Shizuoka Pref., Minami-Izu, Ohi-Toma Leptopetalum biflorum (L.) Neupane & N. Wikstr. KBG99-250 (TI), LC180238*, LC180259*, LC180280*; JAPAN. Okinawa Pref., Iriomote Island, Hoshisuna, Ito, Ohi-Toma 2016061801 (TI), LC180239*, LC180260*, Naiki 7465, “Hedyotis paniculata” (KYO), LC180220*, LC180281*. LC180241*, LC180262*; Ishigaki Island, Tomino, Ohi- Leptopetalum strigulosum (DC.) Neupane & N. Toma & Naiki 2016070101, “Hedyotis paniculata” Wikstr. var. luxurians (Hatus.) Naiki & Ohi-Toma. (TI), LC180221, LC180242*, LC180263*. CHINA. JAPAN. Okinawa Pref., Kita-Daito Island, Ohi- Guangdong, Wang & al. 1258 (IBSC), JF699907, Toma KBG2016-022 (TI), LC180240*, LC180261*, JX111301, JF700056; Hainan, Wang & al. 1146 (IBSC), LC180282*. JF699906, JX111300, JF700055. SINGAPORE. Wang Kadua degeneri (Fosberg) W. L. Wagner & Lorence. SIN03 (IBSC), JX111238, JX111302, JX111120. NEPAL. Cult., Wood 50620 (PTGB), AM939470, AF333371, Neupane 20 (ODU), KP994271, KP005819, KR005757. EU557717. Leptopetalum grayi (Hook. f.) Hatus. JAPAN. Kadua parvula A. Gray. U.S.A. Hawaii, Perlman Tokyo Pref., Ogasawara Islands, Haha-jima Island, Ohi- 12783 (GB), AM939473, AF333375, EU557720. Toma KBG2003-222 (TI), LC180222*, LC180243*, 344 植物研究雑誌 第 91 巻 第 6 号 2016 年 12 月

内貴章世 a，小牧義輝 b，水梨桂子 b，大井・東馬哲雄 b： 分子系統情報に基づくアカネ科シマザクラ属の 2 新組み 合わせ 広義フタバムグラ属 Hedyotis s.l.（アカネ科）は近年の & Sachet) Naiki & Ohi-Toma に，オオソナレムグラを L. 系統解析や形態形質情報をもとに 13 属に分割され，そ strigulosum (Bartl. ex DC.) Neupane & N. Wikstr. var. の一つにシマザクラ属 Leptopetalum がある．シマザクラ luxurians (Hatus.) Naiki & Ohi-Toma に組み替えた．ア 属に所属するかどうか不明であった火山列島固有のアツ ツバシマザクラは小笠原諸島に固有のマルバシマザクラ バシマザクラ Hedyotis pachyphylla，および大東諸島固 L. mexicanum Hook. & Arn. およびシマザクラ L. grayi 有のオオソナレムグラ Hedyotis strigulosa var. luxurians (Hook. f.) Hatus.と単系統となった． は，分子系統解析を行ったところ，シマザクラ属として （a琉球大学熱帯生物圏研究センター， 扱うことが妥当であると判断されたため，アツバシマザク b東京大学大学院理学系研究科附属植物園） ラ を Leptopetalum pachyphyllum (Tuyama ex Fosberg