Biodiv. Res. Conserv. 67: 9-12, 2022 BR C www.brc.amu.edu.pl DOI 10.2478/biorc-2022-0008 Submitted 02.08.2022, Accepted 30.09.2022 Indigofera vicioides Jaub. & Spach (Fabaceae): a new distributional record for the flora of the Eastern Ghats, India Krishnamoorthy Devanathan1 & Narayanasamy Dhatchanamoorthy2* Plant Biology and Systematics lab, Plant Breeding and Bioresources Conservation division, CSIR-Central Institute of Medicinal and Aromatic Plants, Research Centre, Bengaluru, India; ORCID: https://orcid.org/0000-0002-9372-8804 2 Centre for Conservation of Natural Resources, The University of Trans-Disciplinary Health Sciences & Technology, India; ORCID: https:// orcid.org/0000-0001-7568-1224 1 Abstract. Indigofera vicioides Jaub. & Spach (Fabaceae) is a paleotropical species and a rarely found legume of the Southern India. This was the first time it has been recorded in the Eastern Ghats of Tamil Nadu. This article provides a detailed description of this finding together with images and field notes. Key words: Indigofera, leguminosae, southern India, Tamil Nadu 1. Introduction The Indigofera L. belongs to the Indigofereae tribe and is the third largest genus in the Fabaceae family, with about 711 species in total (POWO 2022). They are widely distributed throughout the tropical and the subtropical regions of the world. However, the major centers of diversity are in Eastern, Central and Southern Africa (Schrire et al. 2009; POWO 2022). In India it is represented by 74 taxa (63 species and 11 varieties), of which 25 taxa are of endemic origin (Sanjappa 2020). During the medicinal plant exploration in the Dharmapuri district of Tamil Nadu the authors collected an interesting species of Indigofera, growing in the rocky areas of the scrub forests. The attempt to ascertain the identity of the specimens using the regional floras (Gamble 1918; Britto 1983; Pullaiah et al. 2007; Krishnamurthy et al. 2014; Britto 2019) was unsuccessful. After a closer, careful examination of the respective literature (Gillett 1958; Gillett et al. 1971; Sanjappa 1995) it was identified as Indigofera vicioides Jaub. & Spach (Fig. 1). Furthermore, the specimens have been confirmed with the protologue (Jaubert & Spach 1856) and the herbarium specimens (including the virtual ones) at K and MH. In India it has been reported only in the southern Western Ghats districts such as Tirunelveli and Coimbatore of Tamil Nadu (Vajravelu 1983; Sanjappa 1995; Narasimhan & Irwin 2021) and the Idukki district of Kerala (Pradeep et al. 2009). The present collection from the Palacode reserve forest, in the Dharmapuri district of Tamil Nadu is the topic of the first report about this species in the Eastern Ghats. A brief description, phenological observations and other relevant notes, taken during the field research, have been provided for an easy identification of the species. 2. Taxonomic description Indigofera vicioides Jaub. & Spach, Ill. Pl. Orient. 5(49): 91, t. 481. 1856; Sreemadh., Sci. & Cult. 33: 406. © 2022, Devanathan & Dhatchanamoorthy. This is an open access article licensed under the Creative Commons Attribution-NonCommercialNoDerivs License (http://creativecommons.org/licenses/by-nc-nd/3.0/) VARIABILITY, TAXONOMY AND PHYLOGENY * corresponding author (e-mail: ndhatcha@tdu.edu.in) 10 Devanathan K. & Dhatchanamoorthy N. Indigofera vicioides Jaub. & Spach (Fabaceae): a new distributional record for the flora... 1967; Sanjappa in Hajra et al., Fasc. Fl. India 21: 154. t. 59. 1995; Pradeep et al., J. Econ. Taxon. Bot. 33(4): 825. 2009. (Fig. 1a, 1c, 1d, 1e) Decumbent herbs; branchlets: 10-12 cm high, slender, geniculate, adpressed pilose to glabrescent. Leaves; imparipinnate, c. 4 cm long; 5-11 leaflets; lateral leaflets oblong, 7-15 × 4-5 mm, rounded at base, entire – adpressed ciliate at margins, mucronate at apex; terminal leaflets: elliptic-oblong, 9-15 × 4-5 mm, obtuse at base, glabrous above, adpressed pilose Fig. 1. Photo plate of Indigofera vicioides Explanations: a – habit, b – voucher specimens, c – flowering twig, d – close-up of flowers, e – close-up of pod Biodiv. Res. Conserv. 67: 9-12, 2022 beneath, canaliculate above; petioles: 3-4 mm long; petiolules: c. 1 mm long, strigose; stipules spreading, narrowly triangular or subulate-setaceous, 2-5 mm long, caducous. Racemes; axillary, 2-5 cm long, 4-8-flowered; peduncle: 1.5-2 cm long, pilose. Flowers; c. 4 mm long, reddish-purple; pedicel: c. 1.5 mm long, pubescent; bracts c. 1.5 mm long, ovate, strigose outside. Calyx; 5-lobed, adpressed pubescent; tube c. 1 mm long; equal lobes, c. 1.5 mm long, linear-lanceolate. Corolla exerted; standard ovate, c. 3.5 mm long, obtuse-mucronate at apex, adpressed pubescent outside; elliptic wings, c. 3.5 mm long, ciliate at margins, acute at apex; keels: c. 3.5 mm long, pubescent outside. Pods; sub cylindrical, 8-17 × 2-2.5 mm long, vaguely torulose with c. 0.5 mm wide sutures, pubescent. Seeds; 4-8, sub cylindrical, truncate, pale brown when young and dark brown when mature. P h e n o l o g y : This species’ flowers and fruit setting lasts from September to March. E c o l o g y : Indigofera vicioides grows in rocky areas of dry scrub forests and it is associated with Andrographis serpyllifolia (Rottler ex Vahl) Wight, Boerhavia diffusa Sw., Crotalaria angulata Mill., Cyanotis tuberosa (Roxb.) Schult. & Schult.f., Cyperus compressus L., Euphorbia antiquorum L., Euphorbia tortilis Rottler ex Ainslie, Indigofera glabra L., Oldenlandia umbellata L. Polygala arvensis Willd. and Senna italica Mill. D i s t r i b u t i o n : Global – Africa & India (Kerala and Tamil Nadu). S p e c i m e n e x a m i n e d : ETHIOPIA, In Agris monhams pr. Dscha, 5000 ft., 28 Sep. 1854, Hochstetter 2243 (K000392729 image!). INDIA, Tamil Nadu, Dharmapuri district, Palacode RF, 250 masl, 26.03.2022, N. Dhatchanamoorthy & K. Devanathan 121245 (FRLH). (Fig. 1b). N o t e : This species is often confused with Indigofera arnottii (Kuntze) Peter G. Wilson (syn. I. karnatakana Sanjappa). However, it can be easily distinguished from it by having adaxially glabrous leaflets, 5-8-flowered racemes and a short, densely spreading pubescent pod (Sanjappa 1995). The representation of this species in the Indian herbaria is rare. Sanjappa, Hooper, Ramaswami & Joseph collections of the Tirunelveli district and Shreemadhavan collections from the Coimbatore district of Tamil Nadu are just a few paradigmatic collections of this species. During the present study a single population, consisting of 10 individuals has been located. Author Contributions: Research concept and design: N. Dhatchanamoorthy Collection and/or assembly of data: N. Dhatchanamoorthy, K. Devanathan Data analysis and interpretation: N. Dhatchanamoorthy, K. Devanathan Writing the article: N. Dhatchanamoorthy, K. Devanathan Critical revision of the article: N. Dhatchanamoorthy, K. Devanathan Final approval of article: N. Dhatchanamoorthy References BriTTo S. J.1983. Leguminosae (Fabaceae). In: K. m. maTTheW (ed.). The Flora of Tamilnadu Carnatic, Vol. 3, Part 1, pp. 315-482. The Rapinat Herbarium, St. Joseph's College (Autonomous), Tiruchirappalli. BriTTo S. J. 2019. The Flora of Central and North Tamil Nadu, Fabaceae-Loranthaceae (APG-IV), Vol. 2, pp. 625-1512. The Rapinat Herbarium, St. Joseph's College (Autonomous), Tiruchirappalli. gamBle J. S. 1918. Flora of the Presidency of Madras,Part II (Celasteraceae – Leguminosae-Papilionatae). Adlard & Son Limited, London. gilleTT J. B. 1958. Indigofera (Microchliwis) in Tropical Africa. Kew Bull. Add. Ser. 1: 1-166. gilleTT J. B., Polhill r. m. & verDCourT B. 1971. Flora of Tropical East Africa, Leguminosae (Part 3). Royal Botanic Gardens, Kew. JauBerT h. f. & SPaCh e. 1856. Illustrationes Plantarum Orientalium, Vol. 5. Smithsonian Institution Press, London. KriShnamurThy K. v., murugan r. & raviKumar K. 2014. Bioresources of the Eastern Ghats, Their Conservation and Management. Bishen Singh Mahendra Pal Singh, Dehradun. naraSimhan D. & irWin S. J. 2021. Flowering Plants of Tamil Nadu: A Compendium. Care Earth Trust, Chennai. POWO 2022. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org. Retrieved on 15 July 2022. PraDeeP S. v., Balan a. P. & Kumar r. P. 2009. Two legumes (Indigofera L., Fabaceae) new to Kerala. J. Econ. Taxon. Bot. 33(4): 824-828. Pullaiah T. & Sri ramamurThy K. 2001. Flora of Eastern Ghats Hill Ranges of South East India, Vol. 2. Regency Publications, New Delhi. SanJaPPa M. 1995. Leguminosae-Papilionoideae: Tribe Indigoferae. In: P. K. haJra, a. r. K. SaShTry & m. SanJaPPa (eds.). Fasc. Fl. India 21. Botanical Survey of India, Culcutta. 11 12 Devanathan K. & Dhatchanamoorthy N. Indigofera vicioides Jaub. & Spach (Fabaceae): a new distributional record for the flora... SanJaPPa M. 2020. Fabaceae. In: A. a. mao & S. S. DaSh (eds.). Flowering Plants of India Annotated Checklist Dicotyledons, Vol. 1, pp. 300-446. Botanical Survey of India, Kolkata. SChrire B. D, lavin m, BarKer n. P. & foreST f. 2009. Phylogeny of the tribe Indigofereae (LeguminosaePapilionoideae): Geographically structured more in succulent-rich and temperate settings than in grassrich environments. Am J Bot 96: 816-852. Singh P., KarThigeyan K., laKShminaraSimhan P. & DaSh S. S. 2015. Endemic Vascular Plants of India. Botanical Survey of India, Kolkata. vaJravelu E. 1983. Papilionaceae. In: n. C. nair & a. n. henry (eds.). Flora of Tamil Nadu, India Series I: Analysis, Vol. 1, pp. 90-127. Botanical Survey of India, Coimbatore.