Vigna Sathishiana (Fabaceae): a New Species from Southern Western Ghats, India
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J. Jpn. Bot. 92(4): 193–198 (2017) Vigna sathishiana (Fabaceae): A New Species from Southern Western Ghats, India a, b Anoop Puthuparampil BALAN *, Sreevilas Vasudevan PREDEEP c and Punnakkal Sreedharan UDAYAN aIndian Cardamom Research Institute, Myladumpara, Idukki, Kerala, INDIA; bP.G. Department of Botany, Sree Vidyadhi Raja Nair Service Society College, Vazhoor, Kottayam, Kerala, INDIA; cP.G. Department of Botany, Sree Krishna College, Guruvayur, Thrissur, Kerala, INDIA *Corresponding author: [email protected] (Accepted on February 24, 2017) Vigna sathishiana A. P. Balan & S. V. Predeep, a new species of the genus Vigna Savi of the sect. Ceratotropis (Fabaceae) is described and illustrated from the southern Western Ghats of India. The diagnostic morphological characters, detailed description, illustration and images are presented with notes on habitat, ecology and conservation status. Key words: Fabaceae, India, new species, Vigna, Western Ghats. Vigna Savi (Fabaceae) is a large pantropical elevated to the rank of species and named Vigna genus with 104 species (Lewis et al. 2005) in indica (Dixit et al. 2011). Similarly, Aitawade et seven subgenera viz. Ceratotropis, Haydonia, al. (2012) elevated Vigna mungo var. sylvestris Lasiospron, Macrorhynchus, Plectotropis, Lukoki, Marechal & Octoual to the rank of Sigmoidotropis and Vigna (Marechal et al. species. They also added a new species to the 1978). The subgenus Ceratotropis (Piper) genus, Vigna sahyadriana Aitawade, K. V. Bhat Verdc., also known as Asian Vigna, has its centre & S. R. Yadav from the northern Western Ghats. of diversity in Asia with 21 species (Tomooka et Vigna yadavii Gaikwad, Gore, Randive & Garad al. 2002). The genus has commercial potential (Gaikwad et al. 2014) and Vigna pandeyana as sources of pulses and forage crops and has Gore, S. P. Gaikwad & Randive (Gaikwad et al. a complex taxonomy because of its complex 2015) are two other species recently discovered floral characters and close relationship with the from northern Western Ghats. Latha et al. (2014) genus Phaseolus L. Floral characteristics like described a new species, Vigna konkanensis size of keel petal pocket, twisting of beak, nature Latha, K. V. Bhat, I. S. Bisht, Scariah, Joseph of style and stigma, nature of pod trichomes, John & Krishnaraj, from the west coast of India. number, size, shape and surface nature of seeds, While exploring the legume flora of Western etc. are significant characters in determination of Ghats, the first author collected some interesting the species. Babu et al. (1987) revised the tribe Vigna specimens from the Kallar dam site of Phaseoleae for India and recognized 23 species Idukki district in Kerala state. Critical study of Vigna in the country. Recently, Vigna trilobata with the literature (Baker 1876, Gamble 1918, (L.) Verdc. var. pusilla Naik & Pokle was Verdcourt 1970, Marechal et al. 1978, Babu et al. —193— 194 植物研究雑誌 第 92 巻 第 4 号 2017 年 8 月 Fig. 1. Vigna sathishiana A. P. Balan & S. V. Predeep. A, B. Habit. C. Stem. D. Raceme. E. Pods. F. Pod surface. G. Seed. H. Seedling. I. SEM micrograph of pollen grain. Scale bars: 1 cm (A, B, D, E, H), 5 mm (C), 3 mm (F), 2 mm (G) and 20 μm (I). 1987, Tomooka et al. 2002, Aitawade et al. 2012, V. radiata (L.) Wilczek and V. sublobata (Roxb.) etc.) and authentic specimens in various herbaria Bairiganjan, Panda, Choudhury & Patnaik, revealed that it is a novel taxon with affinity but differing in its small, slender twining habit, to Vigna radiata (L.) Wilczek var. radiata small, unlobed and sparsely hairy leaflets with and V. sublobata (Roxb.) Bairiganjan, Panda, obtuse-acute apices, 2–3-flowered racemes, Choudhury & Patnaik. Pollen morphological smaller flowers and pods, brown seeds with studies also showed significant difference from projected wavy reticulation on testa and smaller the allied taxa, and hence it is described here as a pollen grains with reticulate-heterobrochate new species. exine sculpturing. Taxonomic treatment Type: INDIA. Kerala, Idukki district, Vigna sathishiana A. P. Balan & S. V. Kallar dam site, 09°83ʹN, 77°15ʹE, at ± 1000 Predeep, sp. nov. m, 10 Dec. 2016, Anoop P. Balan 21004 (MH– Vigna sathishiana is allied to the mung bean, holotype; MH, CALI–isotypes). August 2017 The Journal of Japanese Botany Vol. 92 No. 4 195 Fig. 2. Vigna sathishiana A. P. Balan & S. V. Predeep. A. Habit. B. Stipule. C. Bract. D. Bracteole. E. Calyx. F. Standard petal. G. Wings. H. Keels. I. Stamens. J. Pistil. Scale bars: 1 cm (A), 5 mm (H, I), 3 mm (F, J), 2 mm (B, E, G) and 1 mm (C, D). A slender twining herb; stem 60–90 cm long, persistent; petioles 2.5–4 cm long, covered with densely covered with retrorse yellowish brown brown retrorse hairs; stipels 3–4 mm long, linear, hairs of 0.8–1.25 mm long. Leaves pinnately ciliolate; petiolules 2–2.5 mm long, sparsely 3-foliolate, 6–10 cm long including petiole and hairy; leaflets membraneous, sparsely pubescent rachis; stipules peltate, sub-medifixed, 6–8 × above, pilose below along the veins; terminal 2.5–3.5 mm, ovate-elliptic, rounded at base, leaflet 3–4.5 × 2–3.5 cm, ovate-rhomboidal, acute at apex, margins ciliate, 6–8-veined, obtuse-rounded at base, obtuse-acute at apex; 196 植物研究雑誌 第 92 巻 第 4 号 2017 年 8 月 Table 1. Major morphological differences between Vigna sathishiana and its allied species Character V. sathishiana V. radiata var. radiata V. sublobata Habit slender twining herb, 60–90 erect herb, 30–50 cm high robust twining herb, 120– cm long 200 cm long Stem densely covered with densely covered with 2–3 densely covered with 2–3 retrorse, yellowish brown mm long grey hairs mm long brown hairs hairs of 0.8–1.25 mm long Stipules 6–8 × 2.5–3.5 mm, ovate- 8–12 × 5–7 mm, ovate 8–12 × 5–6 mm, ovate elliptic Stipels 3–4 mm long 5–6 mm long 5–8 mm long Leaves 6–10 cm long; leaflets 12–18 cm long; leaflets 20–30 cm long; leaflets obtuse-acute at apex, never acute-acuminate at apex, acute-acuminate at apex, lobed, sparsely pilose sometimes 3-lobed, sometimes 3-lobed, beneath densely hirsute-tomentose densely hirsute-tomentose beneath beneath Racemes 6–12 cm long, 1–3-flowered 4–6 cm long, 4–6-flowered 8–20 cm long, 5–8-flowered Flowers 0.8–1 cm long 1.5–1.8 cm long 1.8–2.2 cm long Standard petal 8–10 × 12–14 mm 9–11 × 16–18 mm 10–12 × 18–20 mm Wing petal 8–10 × 5–6 mm 14–16 × 8–10 mm 15–17 × 8–10 mm Keel petal 10–12 × 5–6 mm; 14–16 × 5–6 mm; lateral 16–18 × 5–7 mm; lateral lateral pocket 1–1.5 mm pocket 3–4 mm long pocket 4–5 mm long long Pods 1–3 per infructescence; 3–4 4–6 per infructescence; 5–8 per infructescence; × 0.3–0.35 cm; covered 5.5–6.5 × 0.4–0.5 cm, 6–6.5 × 0.5–0.6 cm, with appressed brown ferruginously hairy with ferruginously hairy with hairs of 0.4–0.8 mm long 0.6–1 mm long hairs 0.6–1 mm long hairs Seeds 8–10, ca. 3 × 2 × 2 mm, 10–14, ca. 3.5 × 3.5 × 2.5 10–14, ca. 3 × 2.8 × 2.4 mm, tetragonous, parrot green mm, rectangular, green, rectangular, dark brown, turning to brown when testa glossy with obscure testa rough with projected matured, testa rough with reticulation. reticulation projected wavy reticulation Pollen Polar Axis (PA) 37.62 μm (36.47–40.17 μm) 46.48 μm (45.25–47.96 μm) 48.25 μm (45.86–51.42 μm) Equatorial diameter (ED) 36.24 μm (35.15–37.46 μm) 44.64 μm (42.65–47.24 μm) 44.46 μm (41.98–45.86 μm) PA/ED 1.03 μm 1.04 μm 1.08 μm Porus diameter 7.01 μm (6.68–7.24 μm) 8.52 μm (7.95–8.92 μm) 8.18 μm (7.25–8.76 μm) Pollen shape in equatorial view prolate-spheroidal prolate-spheroidal prolate-spheroidal Pollen shape in polar view circular elliptical elliptical Exine surface reticulate-heterobrochate reticulate-homobrochate reticulate-homobrochate lateral leaflets 2.8–3.5 × 2–2.6 cm, obliquely campanulate, pale brown, puberulent; tube ca. 2 ovate. Racemes axillary, 6–12 cm long, mm long; lobes 0.8–1 × 0.8–1 mm, deltoid, ciliate 1–2(–3)-flowered; peduncles 4–10 cm long, at margins, upper two lobes connate except at sparsely retrorse hairy; rachis 0.8–1.5 cm long the tip. Standard petal asymmetrical, 8–10 × 12– with flowers crowded at apex. Flowers 0.8–1 cm 14 mm, obliquely elliptic, emarginate at apex, long, subsessile, pale yellow; bracts 2–2.5 × 1 claw 1–1.5 mm long, auricles ca. 1 mm long; mm, ovate, margins ciliate, deciduous; bracteoles wings 8–10 × 5–6 mm, obliquely obovate, claw 3–3.5 × 1 mm, lanceolate, ciliolate. Calyx ca. 1.5 mm long, auricles ca. 1 mm long; keels August 2017 The Journal of Japanese Botany Vol. 92 No. 4 197 10–12 × 5–6 mm, incurved, beak not spirally taxon is in honor of Dr. C. Sathish Kumar, twisted, claw 1.5–2 mm long, lateral pockets Javaharlal Nehru Tropical Botanic Garden & 1–1.2 mm long. Stamens diadelphous; staminal Research Institute, Thiruvananthapuram, Kerala, sheath 7–8 mm long; filaments 5–6 mm long, for his immense contributions to Indian plant filiform; anthers ac .