Structural variations of cypselas of some taxa of the tribe Calenduleae (Asteraceae), on the basis of morphological observation

Abstract

Present observation has been carried out on the detailed morphological characters of mature cypselas in 3 species (Calendula arvensis L., Calendula maderensis Dc. and Osteospermum vaillantii (Decne.) Norl.), with the help of light microscope. In cypsela of Osteospermum vaillantii and Calendula maderensis, laterally expanded wings are present whereas in Calendula arvensis, wing is absent. In Calendula arvensis, surface is provided with spine like structure. In remaining studied species, this structure is absent. In all the studied cypselas, at the upper part, beak like structures are present. In Calendula maderensis, among the disk cypsela, beak like structure is absent. In Osteospermum vaillantii, carpopodium is triangular in shape whereas in Calendula maderensis and Calendula arvensis, carpopodia are symmetric and complete ring like. However, in all the studied species, carpopodial cells are not quite distinct from the cells of the cypselar wall. An artificial key is made for the easy identification of studied taxa on the basis of morphological characters.