In this study,seedsof 5 species of Acanthophyllum inTurkey were examined with stereomicroscope and scanning electron microscope(SEM) to evaluate the systematic significance of seed microstructure. The seedsof Acanthophyllum were characterizedby oblong or obovate shape. Seeds dorsal and ventral side are generally convex.The largest seeds are found in A.acerosum (2.45 mm in length and 1.16 mm in width). The smallest seeds arefound in A. verticillatum (1.61 mm inlength and 0.84 mm in width). Seeds surface of Acanthophyllum species are fine tuberculate arranged with elongateor polygonal cells like jigsaw puzzle. The shape of suture is sinuous, undulateor dentate. The color of seed is reddish-brown or yellowish-brown. The radicleis on the one side of each seed and just out beyond the hilar notch. Color of seeds, seed length and width, hilumlength and width, suture shape, testa cell shape and the number of suturepoints per plate are important characters in differentiating Acanthophyllum species. By this study, similarities anddifferences between the species of Acanthophyllumgenus are revealed and contributed to taxonomic studies.