Achene Diversity in Some Species of <i>Crepis</i> and <i>Picris</i> (Asteraceae)

ABSTRACT Fifteen achenes of Crepis and Picris were studied using SEM and LM microscopy. The investigated taxa belonging to Crepis are: C. aculeata , C. aspera subsp. aspera, C. aspera subsp. inermis, C. libyca, C. micrantha , C. nigricans , C. sancta subsp. obovata, C. sancta subsp. sancta, C. senecioides . The taxa belonging to Picris are: P. asplenioides , P. cyanocarpa, P. longirostris var. homocarpa, P. longirostris var. longirostris , P. rhagadioloides , and P. sulphurea . Picris longirostris Sch. Bip. var. homocarpa (Eig.) Zareh &amp; Hassan is newly combined. The pericarp of the achenes shows taxonomic and evolutionary significance. The presence or absence of wings, ribs, parenchyma0, or lignified parenchyma can be used as key characters to distinguish between the studied taxa. For studied Crepis and Picris taxa, the characteristics of shape, margins, and sculpture of epidermal cells can distinguish between some closely related species. A comparative morphology and anatomy of achenes, SEM micrographs, drawings of cross sections, and a key to the studied taxa based on achenes characters are provided.