SEM morphology of Stipa tremula (a–e), S. purpurea (f–j) and S. arenosa (k–o). Top of lemma (a–c, f, g, k), callus (d, h, i, m, n), adaxial surface of leaves (l), lemma epidermis (e, j, o). Abbreviations: c = cork cell, h = hook, l = long cell, s = silica body, mh = macro-hair. Vouchers: S. tremula; Kyrgyzstan, Pimenov, Kmaishov, Kamsharaeva s.n. (FRU), Tajikistan, S.S. Ikonnikov 14896 (LE), China, Shinaihaixiang, B. Paszko (KRA); S. purpurea: India, L. Klimeš 619 (KRA), China, Maizang Team 76-7956 (PE); S. arenosa: China, W.J. Roborowski 318 (KRA 476855), China, B-z. Guo s.n. (PE 707226).