J. Botan. Soc. Bengal 67 (1) : 55-61 (2013) © Botanical Society of Bengal, Department of Botany, University of Calcutta, Kolkata 700 019, India Cypselar diversity of some species of the tribe Lactuceae (Compositae) Bidyut Kumar Jana* and Sobhan Kr. Mukherjee Taxonomy and Biosystematics Laboratory, Department of Botany, University of Kalyani, Kalyani, Nadia, West Bengal, India Received: 16.03.2013 Accepted : 14.05.2013 Published: 24.06.2013 Mature, identified, cypselas of four species, belonging to three genera (Lactuca serriola, Picris hieraciodes, Tragopogon orientalis and Tragopogon pratensis ) were studied with the help of light microscope to observe the different morphological and anatomical characters. Special attention has been given to the size, shape, orientation of surface hairs of mature cypselas, number of ribs on the surface, structure of carpopodia and their cellular orientation, structure of pappus bristles, stylopodia etc. Among the studied cypselas, all are homomorphic. Heteromorphism is absent. Among the studied cypselas, beak like structures are present in case of Tragopogon pratensis, Tragopogon orientalis and Lactuca serriola whereas in Picris hieraciodes, beak like structure is absent. Pappus is homomorphic and represented by plumose-capillary type of pappus bristles. Other than the cypsela of Tragopogon pratensis, true carpopodia are present. Stylopodia are not clearly observed. Anatomically, pericarp is differentiated into epicarp and mesocarpic zone or pericarp is differentiated into epicarp, mesocarp and endocarp. Mesocarpic region is heterogenous, in case of the cypsela of Tragopogon pratensis and Tragopogon orientalis whereas in two other studied cypselas, mesocarpic regions are homogenous. Within the mesocarpic region of the cypsela of Lactuca serriola and Picris hieraciodes, vellicular cavities are present. In the cypsela of Tragopogon orientalis, secretary cavity is present in mesocarpic region. Secretary cavity is absent in the cypsela of remaining studied species. Testa attached with cypselar wall and made up of 2 layers parenchymatous ( Tragopogon pratensis and Tragopogon orientalis), 1 layer parenchymatous (Lactuca serriola and Picris hieraciodes) cells. Based on the aforesaid morpho-anatomical characters, an artificial key to the studied species is constructed for the proper identification of cypselas. Key words: Cypselar diversity, Lactuceae, Compositae INTRODUCTION Among the 43 tribes of Asteraceae ( Funk et al. 2009), Lactuceae has a great diversity among its different species and is easily recognized tribe of the family Asteraceae. Previously, the name of this tribe was Cichorieae (Cronquist, 1955; Jeffrey, 1966). Nowadays, it is Lactuceae (Bremer, 1994). According to Bremer (1994), this tribe consists of more than 1550 species under 98 genera. According to Kadereit and Jeffrey (2007); this tribe has 86 genera and 12 subtribes. Number of species of this tribe is greatly variable due to the different view of its circumscrip- tion. It is easily recognizable among the tribes of Asteraceae by the presence of milky latex and ligulate corolla (Jeffrey, 2007). According to Bremer ( 1996), this tribe is a monophyletic group and it has been incorporated within the subfamily Cichorioideae along with 3 other tribes. The available information ( Das and Mukherjee, 2008; Jana and Mukherjee, 2012; Dasgupta and Mukherjee, 2007; Bremer, 1994; Mukheijee and Sarkar, 1995; Beliaeva and Boyko, 1980; Beliaeva, 1982; Singh et al, 1973) regarding the morpho-anatomical structures of cypselas, of this tribe is fragmentoiy. These available literature has indicated that capsular features are important for the delimitation of taxa. Thus the study of cypselar mor- phology and anatomy of some members of the tribe