Comparative investigation of macroand microscopic elements of different parts of Onopordum acanthium and Carduus nutans

Onopordum acanthium L. and Carduus nutans L. belong to the tribe Cardueae, family Asteraceae, The similar macro features and nearest habitats provide the difficulties to differentiate each plant during collection. Onopordum acanthium is a medicinal plant using in the folk medicine. It is a potential anti-inflammatory and antitumor agent for preventive usage. 

Objective. The aim of this work is to found and describe macro- and micro features of these similar species of the tribe Cardueae. 

Materials and methods. In this research the samples of Onopordum acanthium and Carduus nutans collected during flowering and fruiting were used. The external features were described according to the XIV edition of the State Russian Pharmacopeia. Microanalysis was carried out with aerial parts and roots. The photos of micro preparations were taken. 

Results. These two species differ with respect to anatomy of leaves, stem wings, inflorescences. Micro analysis provide that Carduus nutans flower stalk has more ribs and densely tomentous; a stem of Onopordum acanthium has wings all over its surface; several bundles in the stem are offset and flipped to 90°; there are trichomes on both sides of leaves of Onopordum acanthium , also there are salt cells on the down side; the root medullary rays and first and secondary xylem are different; and phloem is pigmented in Onopordum acanthium. 

Conclusion. The results of this work may be used in the instruction of collection of medicinal raw material of Onopordum acanthium.