*Bidyut Kumar Jana, Ruksona Auju and Sobhan Kr. Mukherjee

Taxonomy and Biosystematics Laboratory, Department of Botany, University of Kalyani, Kalyani-741235, Nadia, West Bengal (India) Emails: *janabidyutkumar@yahoo.com, sobhankr@yahoo.com, sobhankr@gmail.com

ABSTRACT

The present paper deals with the detailed morpho-anatomical features of cypselas among 5 species of the tribe Heliantheae (Asteraceae). Among the studied species, in case of Cosmos sulphureus and Bidens frondosa, cypselas are heteromorphic than the remaining 3 other studied cypselas, where they are homomorphic. Except the cypsela of Bidens frondosa, in remaining 4 studied cypselas, pappus are absent. In the cypsela of Bidens frondosa, pappus is awn like in nature.In all the studied cypselas, phytomelanin layer exists in the surface, in the form of different ornamentation. Cross sections of cypselas show variable outline, i.e. more or less rounded (Bidens), tetrangular (Cosmos), triangular (Sclerocarpus), and oval (Zinnia). Anatomically, phytomelanin layer is present in the mesocarpic region of each studied cypselas. Each cypsela has 2 cotyledons and their orientation is also variable. In Bidens frondosa, cotyledons are arranged at right angle to the axis of cypsela whereas in case of Cosmos sulphureus, Sclerocarpus africanus, Zinnia pauciflora and Zinnia verticillata, cotyledons are placed obliquely to the axis of cypsela

Key words : Cypselar features; Heliantheae; Asteraceae

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