SEM morphology of the floret of Ptilagrostis tibetica (a–c), P. bhutanica (d–f), P. chingii (g–i), P. contracta (j–l), P. duthiei (m–o) and P. yadongensis (p–s). Callus and the lower part of the lemma (a, d, g, j, m, p), epidermal pattern of the middle part of lemma (b, e, h, k, n, r), top of lemma (c, f, i, l, o, s). Abbreviations: c = cork cell, h = hook, l = long cell, s = silica body, m = macro-hair.