Anatomical Study and Pollen Micromorphology of <i>Onopordum</i> L. in Iran

In this study, pollen micromorphological structure, leaf and stem anatomy structure of six species of Onopordum ( O. acanthium L., O. armenum Grossh., O. carduchorum Bornm. & Beauv., O. carmanicum (Bornm.) Bornm., O. heteracanthum C. A. Mey and O. leptolepis DC) were examined with different repetitions. About 17 qualitative anatomical features were statistically analyzed. Glandular trichome, cortex fiber tissue, embowed in subsidiary vascular, its fiber tissue and vascular sheath extensions, adaxial collenchyma tissue and types of adaxial and abaxial stomata were distinct characters in separating of the species. In palynologic studies based on P/E ratio, 2 types of pollen grains were observed: oblate- spheroidal and suboblate. SEM study of the exine showed echinate, reticulate and perforate sculpturing in all six species.