Caldesia oligococca (F. von Mueller) Buchenau [Alismataceae]: a new record for Assam in India S. Hazarika 1 and S. K. Borthakur Department of Botany Gauhati University, Guwahati 781014, Assam, India 1 Corresponding author: Department of Botany, A. D. P. College, Nagaon 782002, Assam, India E-mail: sonjirahazarika@gmail.com [Received 08.12.2014; Revised & accepted 20.05.2015; Published 30.06.2015] Caldesia oligococca (F. von Mueller) Buchenau [Alismataceae] collected from Hatichung of Nagaon District, Assam is reported as new distributional record for the state. Key words: Hydrophytic flora, Caldesia oligococca, New Record, Assam. Abstract INTRODUCTION Caldesia Parlatore (Alismataceae) is one interesting wetland genus. It is a scapigerous herb with glabrous submerged or floating leaves having peniculate pyramidal inflorescence with whorls of 3 branches and flowers, sepals persisting in fruit, nutlets laterally somewhat flattened, ridged, warty or spiny. The genus comprises of only four species and distributed mainly throughout the Old World tropics and of which three species have been reported so far from the Indian territory viz., C. grandis G. Semuelsson, C. oligococca (F. von Mueller) Buchenau and C. parnassiifolia (Bassi ex Linnaeus) Parlatore (Cook 1996). C. janaki- ammalii Guha & Mandal has been reported as new species from Lower Bengal (Guha & Mandal 2003) and was not included in “Aquatic and Wetland Plants of India” by Cook (1996). In North-Eastern region the genus is represented by two species viz., C. grandis and C. oligococca, both from Khasi and Jayantia Hills of Meghalaya (Rao & Verma 1976). During the botanical collections from different water bodies in Nagaon district of Assam, an interesting specimen was collected by the authors during the month of October, 2012 and 2013 respectively from temporary water ditches in the Hatichung area along the margins of paddy fields. On critical study and scrutiny of literature (Subramanyam 1962; Cook 1996; Ghosh 2005) and herbarium materials in ASSAM the specimen was identified as Caldesia oligococca (F. von Mueller) Buchanan . Further scrutiny of literature (Rao & Verma 1976; Hajra & Jain 1996; Jain & Hajra 1978; Satyanarayana 1962; Baruah & Baruah 2000; Baruah 2003; Bora & Kumar 2003; Barooah & Mahanta 2006; Gogoi 2003, 2006; Sharma & Borthakur 2009; Sharma & Saikia 2010) revealed that Caldesia oligococca has not been reported so far from Assam and hence a new record for the state. The taxonomic descriptions, Photographs, growth form and distribution are provided below. Caldesia oligococca (F. von Mueller) Buchanan in Bot. Jahrb. Syst. 2: 479. 1882; Hartog in Fl. Males. 1, 5: 320. 1957; Alisma oligococcum F. von Mueller, Fragm.1: 23. 1858; Hooker f., Fl. Brit. India 6: 560. 1893; Subramanyam, Aquatic Angiosperm 84. 1962; Rao & Verma, Bull. Bot. Surv. Ind. 18: 37. 1976; Cook, Aquat. Wet. Pl. Ind. 37. 1996. Pleione 9(1): 103 - 106. 2015. ISSN: 0973-9467 © East Himalayan Society for Spermatophyte Taxonomy