Carpological investigations on some Cirsium (Asteraceae, Carduoideae) taxa from NE Anatolia

Abstract

In the present study, morphological and anatomical structures of cypsela – 12 Cirsium Miller (Carduoideae, Asteraceae) taxa belonging to two sections (sect. Cirsium and sect. Cephalonoplos) were investigated in detail with using stereomicroscope and light microscope. The taxa were evaluated comparatively in the aspect of carpological variations and their anatomies were presented in here for the first time. Morphological features including size, shape and colour of cypselae were examined. From anatomical observations, anatomical structures of pericarp, as well as the structure of testa were described. Cypselae colours differ from light brown to stramineous, sometimes with blackish striations. Their shapes change from oblong to oblanceolate, rarely obovate. The largest cypselae are present in C. echinus (1.59±0.03 mm × 4.68±0.07 mm) and the smallest ones are found in C. subinerme (1.20±0.02 mm × 2.97±0.05 mm). The pericarp is characterised by almost parenchymatous cells, while the testa is composed of lignified sclerenchymatous cell lines and crushed cells group. Secretory structure in testa bundle was evaluated. Results obtained from this study were compared with the present data in literature. Overall, morphological and anatomical characteristics of cypselae provide useful taxonomic markers in their classifications of the studied taxa of Cirsium but not distinctive for their sectional levels.