ORIGINAL ARTICLE Morphological and molecular characterization of Thamnocalamus spathiflorus subsp. spathiflorus at population level Samik Bhattacharya Æ Jayadri Sekhar Ghosh Æ Malay Das Æ Amita Pal Received: 29 January 2008 / Accepted: 12 August 2008 / Published online: 30 April 2009 Ó Springer-Verlag 2009 Abstract Comprehensive morphological characterization and an incidence of gregarious flowering in Thamnocal- amus spathiflorus (Trin.) Munro subsp. spathiflorus are described. Twenty-eight key vegetative characters as well as reproductive morphology were studied. They are in gross agreement with prior taxonomic descriptions, yet more elaborate. Statistical analyses of the quantitative vegetative characters revealed significant high variability existing between populations, but not within populations. However, DNA fingerprinting analyses by applying highly polymorphic random primers could not detect any polymorphism either between populations or within populations. Insignificant within-population variability indicates possibility of clonal propagation from the donor(s) possessing similar genetic background and thus reducing genetic variability. Keywords Morphology Á Gregarious flowering Á DNA fingerprinting Á Genetic diversity Introduction Thamnocalamus spathiflorus (Trin.) Munro subsp. spath- iflorus belongs to the subtribe Thamnocalaminae (=Arundinariinae) under subfamily Bambusoideae. The group includes several cold-tolerant members (http://www. bambooresearch.com/Specie/species-thamno.html) and is usually found in fragile ecosystems like canal banks, steep terrain and eroding hills. Hence, they play important role in stabilizing top soil by its widespread rhizomatous rooting system. On the basis of the flowering cycle, bamboos have been categorized in three major groups: annual flowering, spo- radic or irregular flowering and gregarious flowering (Brandis 1899). In gregarious flowering, the onset of the reproductive phase occurs simultaneously in all the mem- bers of a cohort or species across a wide area and subsequently dies together. Records of bamboo flowering are limited in the literature (Siefriz 1950; Filgueiras and Pereira 1988; Ramanayake and Yakandawala 1998; Bhat- tacharya et al. 2006). In India, the past incidents of mast flowering in T. spathiflorus were recorded during 1818–1821 from North-Western Himalayas (Fig. 1, location A), during 1881–1882 from Jaunsar and Tehri Garhwal (Broun 1886; Fig. 1, location B), in 1942 from Chakrata (Fig. 1, location C) and in 2002 from Uttaranchal (Naithani et al. 2003; Fig. 1, location D). The estimated flowering period in T. spathiflorus is 60 years (Naithani et al. 2003). Here, we report the incidence of a gregarious flowering event in T. spathiflorus subsp. spathiflorus growing over an area of approximately 3.5 km 2 in Sikkim, India. This incited us to re-evaluate the reproductive characteristics of the subspecies and compare with previous descriptions. Nevertheless, like most bamboo species, the identification of T. spathiflorus subsp. spathiflorus is usually dependant on vegetative Electronic supplementary material The online version of this article (doi:10.1007/s00606-008-0092-1) contains supplementary material, which is available to authorized users. S. Bhattacharya Á J. S. Ghosh Á A. Pal (&) Plant Molecular and Cellular Genetics Section, Bose Institute, P 1/12 CIT Scheme VIIM, Kolkata 700054, India e-mail: amita@bic.boseinst.ernet.in M. Das Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA 123 Plant Syst Evol (2009) 282:13–20 DOI 10.1007/s00606-008-0092-1