Didymosperma gracilis, a New Synonym of Wallichia nana (PDF)

Vol. 31(2): Mehmud & Roy 89 89–91 (2...

Vol. 31(2): Mehmud & Roy 89 89–91 (2021) RHEEDEA Journal of the Indian Association for Angiosperm Taxonomy ISSN: 0971-2313 (Print edition) ISSN: 2582-2438 (Online edition) https://dx.doi.org/10.22244/rheedea.2021.31.02.10 Didymosperma gracilis, a new synonym of Wallichia nana (Arecaceae) Mehmud S.* & H. Roy Department of Botany, Cotton University, Panbazar, Guwahati, Assam – 781 001, India *E-mail: [email protected] Abstract: Didymosperma gracilis Hook.f. is merged here Pradesh and Manipur (Renuka & Sreekumar, 2012). as a synonym of Wallichia nana Griff. based on Only A. westerhoutii was recorded so far from Assam examination of the protologue, type materials and fresh (Barbhuiya, 2014; Mehmud & Roy, 2021). All these collections. Both are similar in their habit, habitat, size three species of Arenga in northeastern India bear and nature of leaflets and fruits. linear leaflets and their diameter of stem ranges from Key words: Nomenclature, Northeast India, Palm. 13–60 cm (Renuka & Sreekumar, 2012). Didymosperma gracilis was described by Hooker (1894) based on Booth’s collection from Daphla Introduction Hills in Assam (now Dafla Hills in Arunachal All species of Didymosperma H.Wendl. & Drude Pradesh). The type specimen at K (K000400178 ex Hook.f., except Didymosperma gracilis Hook.f., digital image!) has a part of stem with two leaves, were either placed under Arenga Labill. ex DC. incomplete or damaged, fibrous ligule and alternate, (Mogea, 2004; www.theplantlist.org) or Wallichia serrated, abaxially white leaflets. The apical leaf near Roxb. (Henderson, 2007, 2009; www.theplantlist. the fruiting branch is comparatively shorter than org). Henderson (2007) revised the genus Wallichia the other leaves. The fruiting branch is terminal, and raised the question of the existence of the species with three rachillae, having few elliptic-oblong D. gracilis as he not only mentioned the name under fruits having persistent perianth and acute lobes and “excluded and doubtful names”, but also stated that brown, elliptic-curved or concavo-convex seeds. “The type specimen is so poor that it is not possible The information associated with the protologue and to identify this specimen”. Out of eight species of type material of D. gracilis is not matching with Wallichia (Henderson, 2007), five species are found any species of Arenga, but shows perfect match with in India (Renuka & Sreekumar, 2012; Mehmud & the protologue of Wallichia nana Griff. (Griffith, Roy, 2020). Three species occur in Assam (Mehmud 1845) and information related to types (Griffith, & Roy, 2021). Whereas Arenga is represented by 1850; Henderson, 2007; Reveal & Nixon, 2013), 24 species (Pillai et al., 2020) with five species in especially when features of the stem, leaf, fruit and India. Northeast India harbours three species viz. seed are compared. Moreover, the taxonomic A. micrantha C.F.Wei from Sikkim and Arunachal description and note added to W. nana in relevant Pradesh, A. obtusifolia Mart. from Arunachal studies (Henderson, 2007; Renuka & Sreekumar, Pradesh, and A. westerhoutii Griff. from Arunachal 2012; Mehmud & Roy, 2020, 2021), and examination of the fresh collections in different stages (Fig. 1) in the present study gives additional Received: 26.01.2021; Revised & Accepted: 13.05.2021 support to consider Didymosperma gracilis as a Published Online: 30.06.2021 synonym of Wallichia nana. 90 Didymosperma gracilis, a new synonym of Wallichia nana Fig. 1. Wallichia nana Griff.: a. Young plant; b-d. Young fruits (arrow showing small leaf); e. Small leaf near the infructescence (arrow); f. Infructescence with dry fruit (arrow) and persistent perianth; g. Longitudinal cut of an immature fruit (1 & 2), seed (3) and a complete fruit (4); h. Dry seeds with embryo in central position (arrow). Taxonomic Treatment H.Wendl. & Drude in Kerchove, Palmiers 243. Wallichia nana Griff., Calcutta J. Nat. Hist. 5: 488. 1878. Blancoa nana (Griff.) Kuntze, Revis. Gen. Pl. 1845. Harina nana (Griff.) Griff., Palms British East 2: 727. 1891. Arenga nana (Griff.) H.E.Moore, India 176. 1850. Didymosperma nanum (Griff.) Principes 4: 114. 1960. Type: INDIA, Assam, s.d.,  Mehmud & Roy 91 Jenkins s.n. (A [00421704 digital image!], BH n.v., Literature Cited BR [BR0000006876920 digital image!, BARBHUIYA H.A. 2014. Forty new additions to the BR0000006877255 digital image!], K [K000400177 angiospermic flora of Assam. Journal on New Biological Reports 3(3): 277–287. digital image!], L [0042007 digital image!], NY n.v., P [P00491422 digital image!]). GRIFFITH W. 1845. The palms of British East India. Calcutta Journal of Natural History 5: 1–103, 311–491. Didymosperma gracilis Hook.f., Fl. Brit. India 6(18): GRIFFITH W. 1850. Palms of British East India: posthumous 420. 1894. Type: INDIA, Arunachal Pradesh, papers bequeathed to the Honourable the East India Company. Periodical Experts Book Agency, Delhi. Dafla (“Daphla”) Hills, s.d., Booth s.n. (holo K [K000400178 digital image!]). syn. nov. Fig. 1. HENDERSON A. 2007. A revision of Wallichia (Palmae). Taiwania 52(1): 1–11. https://doi.org/10.6165/ Specimens examined: INDIA, Arunachal Pradesh, tai.2007.52(1).1 Dibang valley, 26.03.1999, M. Bhaumik 2168 HENDERSON A. 2009. Palms of southern Asia. Princeton University Press, United States of America. (ASSAM). Assam, Jorhat, Nambor R.F., 21.11.1964, S.K. Kataki 41649 (ASSAM 44563); HOOKER J.D. 1894. Flora of British India. Volume 6. L. Reeve & Co. Ltd. The Oast House, Brook, Ashford, Tinsukia, Bherjan, N 27°3'27.2", E 95°22'14.4", Kent. alt. 84 m, 03.09.2019, Selim Mehmud 169 (ASSAM, MEHMUD S. & H. ROY 2020. Anatomical studies on Herbarium of Department of Botany, Cotton Wallichia nana Griff., a wild palm of Assam, India. University); West Karbi Anglong, Nellie to Reinwardtia 19(2): 97–102. https://doi.org/10.14203/ reinwardtia.v19i2.3920 Umapanai road, 13.02.2020, Selim Mehmud 242 MEHMUD S. & H. ROY 2021. Diversity and distribution (Herbarium of Department of Botany, Cotton of palms (Arecaceae) in Assam, India. Check List 17(1): University). 69–93. https://doi.org/10.15560/17.1.69 MOGEA J.P. 2004. Four new species of Arenga (Palmae) from Indonesia. Reinwardtia 12(2): 181–189. https:// Acknowledgements doi.org/10.14203/reinwardtia.v12i2.67 We are grateful to the Head of the Department of PILLAI A.R., RIYAS C.T. & K.K. SABU 2020. A review Botany, Cotton University. We are also obliged to on the unexplored and underutilized Arenga species in the authorities of Assam Forest Department; India. Current Botany 11: 226–232. https://doi.org/ 10.25081/cb.2020.v11.6252 Director of Botanical Survey of India for herbarium consultations (ASSAM and CAL); Dr. Sarah Phillips RENUKA C. & V.B. SREEKUMAR. 2012. A field guide to the palms of India. Kerala Forest Research Institute, of Royal Botanic Gardens, Kew for providing high Peechi. resolution images of the type of Didymosperma REVEAL J.L. & K.C. NIXON. 2013. The palm type gracilis; and authorities of A, BR, L, NY, P for digital collection in the Liberty Hyde Bailey Hortorium (BH). herbarium. Phytoneuron 79: 1–46.