J. Jpn. Bot. 93(2): 104–120 (2018) Grona, a Genus Separated from Desmodium (Leguminosae Tribe Desmodieae) a,* b Hiroyoshi OHASHI and Kazuaki OHASHI aHerbarium TUS, Botanical Garden, Tohoku University, Sendai, 980-0862 JAPAN; bSchool of Pharmacy, Iwate Medical University, Yahaba, Iwate Pref., 028-3694 JAPAN *Corresponding author: [email protected] (Accepted on November 4, 2017) The genus Desmodium is polyphyletic as suggested by recent molecular analyses. Desmodium sections Nicolsonia and Sagotia constitute a monophyletic group distinct from that which includes Desmodium scorpiurus, the type of the genus. The oldest generic name applicable to the monophyletic group is Grona Lour. It was established on the basis of Grona repens Lour. (= Desmodium heterocarpon (L.) DC.) in 1790, but the name is rejected under the conserved name Desmodium Desv. published in 1813. Desmodium and Grona in a new sense are separated from each other based on morphological and palynological characters and evidence from molecular analyses. Grona is, therefore, resurrected in order to accommodate the species belonging to Desmodium sections Nicolsonia and Sagotia under ICN Art. 14.6. The present paper provides 41 new specific combinations with 13 new infraspecific combinations underGrona. Key words: Desmodium, Desmodium heterocarpon, Desmodium triflorum, Fabaceae, Grona, Loureiro, Nicolsonia, Nogra, Sagotia, tribe Desmodieae. The circumscription of the genus Desmodium Akschindlium (Ohashi 2003), Hanslia (Ohashi has long been controversial. It is ‘the main 2004b), Monarthrocarpus (Ohashi 2004b), problem’ in the tribe Desmodieae (Ohashi et al. Ougeinia (Ohashi 2005), Ototropis (Ohashi and 1981, Ohashi 2004a). Bentham’s generic concept Ohashi 2012a) and Verdesmum (Ohashi and of Desmodium (Bentham 1865) had widely Ohashi 2012b) are resurrected or produced. The been accepted, but Schindler (1928), Hutchinson taxonomic history of Desmodium and its allied (1964), Ohashi (1973) and Ohashi and Ohashi genera was reviewed by Pedley (1999) and Lima (2012a, b) split the genus into Desmodium and et al. (2014). its satellite genera. The broadest circumscription The tribe Desmodieae contains 32 genera of the genus was published by Bentham (1865), (Ohashi 2005, Ohashi and Ohashi 2012a, b) while the narrowest by Schindler (1928) (Ohashi classified into the Lespedeza group (three 2004a). Ohashi’s circumscription of the genus genera), the Phyllodium group (12 genera) and (1973) was intermediate between these two, but the Desmodium group (17 genera), based mainly it has been modified since 1996. Trifidacanthus on results of an analysis of rbcL by Kajita et (Ohashi et al. 1996), Ohwia (Ohashi 1999), al. (2001). Desmodium is the core genus in the Hylodesmum (Ohashi and Mill 2000), Desmodium group. Polyphyly of Desmodium —104— April 2018 The Journal of Japanese Botany Vol. 93 No. 2 105 Fig. 1. Calyxes (opened view from inside) of Grona and Desmodium sect. Heteroloma. a. Grona barbata (Sauliére 506, K). b. G. triflora (Kanai & H. Ohashi 25747, TI). c. G. heterophylla (Tuyama in 1935, TI). d. G. rubra var. rubra (Katsumata s.n. in 1910, TI). e. Desmodium concinnum (Stainton & al. 8863, TI). f. D. oblongum (Iwatsuki & Fukuoka T.3211, TI). Adaxil lobes (connate lobe) are drawn on the left side. Scale bar: 2 mm. Reproduced with modification from figs. 52 and 53 in H. Ohashi, Ginkgoana 1 (1973) [ H. Ohashi]. was presented by Kajita et al. (1996, [2010 at molecular analyses indicates that D. scorpiurus 5th Legume Conference]), though the results is placed in a clade different from that composed were unpublished. Currently, the polyphyly of of D. heterocarpon, D. heterophyllum and Desmodium was demonstrated by Jabbour et other species belong to the subgenus Sagotia. al. (2018) in molecular phylogenetic analysis of A new classification system of Desmodium is, chloroplast (rbcL, psbA-trnH) and nuclear (ITS- therefore, needed for Desmodium based on the 1) DNA sequences. Desmodium was shown monophyletic group previously included in as polyphyletic separated into three clades: Desmodium. Desmodium heterocarpon-heterophyllum, D. The subgenus Sagotia is the most velutinum, and D. adscendens-intortum clades complicated group in the genus Desmodium. in their phylogenetic tree of cpDNA (Jabbour et Ohashi (1973) characterized the subgenus al. 2018, figs. 2, 3) and chronogram of cpDNA approximately by having terminal racemes (Jabbour et al. 2018, fig. 4). Moreover,Hegnera , composed of 2–4-flowered fascicles, small Uraria crinita, Leptodesmia, Codariocalyx, flowers lacking bracteoles at the calyx-base, Christia (only in fig. 2), Mecopus (only in fig. 4- or 5-lobed calyx, diadelphous stamens, 2), Melliniella, and Alysicarpus were presented mostly sessile ovary without disk around the between the three Desmodium clades in their base, and rather small-sized articles of the phylogenetic trees in figs. 2 and 4 (Jabbour et al. loments. He classified the subgenus into six 2018). sections: Chalarioidea, Oxytes, Heteroloma, During our systematic studies of Desmodium Nicolsonia, Renifolia and Sagotia. The sections on the basis of morphology, palynology and Chalarioidea and Oxytes are monotypic and molecular analyses, we obtained more detailed differ from others in having asymmetrical results of polyphyly of the genus (Ohashi et persistent stipules. Renifolia includes two species al. in press). Desmodium scorpiurus, the type distinct from others by their unifoliolate leaves species of the genus, was not included in the with a reniform leaflet and calyxes with lobes result of Jabbour et al. (2018), but our result of shorter than the tube (Ohashi 1973, Dy Phon et 106 植物研究雑誌 第 93 巻 第 2 号 2018 年 4 月 al. 1994). examined by Bentham (1865). He considered The remaining three sections are similar in the genus as similar to Kennedia and Galactia having symmetrical stipules, calyxes with lobes of the tribe Phaseoleae. Merrill (1935) corrected longer than the tube. Sections Nicolsonia and the misapplication of Grona sensu Bentham to Sagotia are separated from sect. Heteroloma in Phaseoleae and accommodated the species of having 5- or 4-lobed calyx of which the adaxial Grona other than G. repens then known to his lobes are bifid at the apex and lacking secondary new genus Nogra. Merrill recognized Grona as bracts, whereas in Heteroloma the adaxial a valid genus and suggested it to be rejected for lobes are entire or slightly bifid (Fig. 1) and the Desmodium. Schindler (1928) determined the secondary bracts are present or sometimes absent holotype of Grona repens Lour. as Desmodium (Ohashi 1973). The sculpture of pollen grains siliquosum DC., which is a synonym of D. is rugulate-verrucate or fine rugulate, rarely heterocarpon subsp. heterocarpon var. strigosum fine rugulate to microreticulate in Nicolsonia van Meeuwen (Ohashi 1973). After examining and Sagotia (Fig. 2), but it is reticulate in the holotype on the image scanned by BM Heteroloma. (BM000839659), we confirm the plant as D. Our molecular analyses support that sections heterocarpon subsp. heterocarpon. Nicolsonia and Sagotia constitute a single monophyletic group, but Heteroloma is not. Taxonomic treatment The Nicolsonia and Sagotia group is clearly Grona Lour., Fl. Cochinch. 2: 459 (1790). separated from that including Desmodium Type: Grona helerocarpa (L.) H. Ohashi & K. scorpiurus. After examining eight species of Ohashi (= Grona repens Lour.). the subgenus Sagotia sect. Nicolsonia and Perrottetia DC. in Ann. Sci. Nat. 4: 95 (Jan. sect. Sagotia including D. heterocarpon and 1825), nom. illeg., non Kunth (1824). Type: D. heterophyllum (Ohashi et al. in press), it is Perrottetia barbata (L.) DC. strongly supported that the two sections should Nicolsonia DC., Prodr. 2: 325 (mid Nov. be treated as one group. 1825) [substitute name for Perrottetia DC. The oldest generic name for the Nicolsonia (1825), non Kunth (1824)]; Mem. Leg. 7: 311, t. and Sagotia group is the genus Grona. It was 51 (1826); Schindl. in Repert. Spec. Nov. Regni created by Loureiro (1790) based on Grona Veg. 23: 357, in adnot. (1927). Type: Nicolsonia repens Lour. (Holotype BM000839659) from barbata (L.) DC. (lectotypified by Schindler Vietnam in 1790. The species is a synonym 1927). of Desmodium heterocarpon (L.) DC., which Nicholsonia Span., Companion Bot. Mag. 1: belongs to the section Nicolsonia (DC.) Benth. 346 (1836), sphalm. ut ‘Nicholsonia oxalidifolia in the subgenus Sagotia in Desmodium (Ohashi Span.’ 1973). Nomenclatue of the generic name Sagotia Duchass. & Walp. in Linnaea Grona Lour. was fully discussed by Merrill 23: 737 (1851) [Type: Sagotia triflora (L.) (1935). Although the generic name Grona was Duchass. & Walp.], nom. rej. vs. Sagotia Baill. rejected under the conserved name Desmodium [Euphorbiaceae] in Adansonia 1: 53 (1860), Desv. published in 1813 (Brummitt 1978, ICN nom. cons. App. III), the name can revive here under ICN Desmodium sect. Sagotia (Duchass. & Art. 14.6 (McNeill et al. 2012). We propose, Walp.) Benth., Miq., Pl. Jungh. 2: 222, adnot. therefore, resurrection of the genus Grona Lour. (1852); Benth. in Benth. & Hook. f., Gen. Pl. in order to accommodate Desmodium sections 1: 520 (1865); H. Ohashi in Ginkgoana 1: 233 Nicolsonia and Sagotia. (1973); Pedley in Austrobaileya 5: 227 (1999). – The holotype of Grona repens Lour. was [Meibomia sect. Sagotia (Walp.) Kuntze in Post, April 2018 The Journal of Japanese Botany Vol. 93 No. 2 107 Fig. 2. Pollen sculpture patterns of Grona barbata [India. Sauliére 506 K] (A–C). G. heterocarpa subsp. angustifolia [Thailand. Tagawa & al. 2456, TUS] (D–F). G. triflora [Taiwan. Taipei. Ohashi & al. 8809, TUS] (G–I) and G. auricoma [Thailand. Put 478, TUS] (J–L). A, D, G, J. Mesocolpium in equatorial view. B, E, H, K. Sculpture of mesocolpium. C, F, I, L. Aperture in equatorial view. Scale bars: 1 µm (B, E, H, K), 5 µm (A, C, D, F, G, I, J, L). 108 植物研究雑誌 第 93 巻 第 2 号 2018 年 4 月 Lex. Gen. Phan. 357 (1903), nom. nud.]. sometimes elliptic-oblong, abaxial suture slightly Desmodium sect. Nicolsonia (DC.) Benth. or distinctly constricted, hocked-hairy on lateral in Miq., Pl. Jungh. 2: 222 (1852); Benth. in surfaces. Seeds compressed, mostly broadly Benth.