To evaluate nutlets characteristics for systematic relationships, a comprehensive morphological and micro-morphological study of the nutlets of 16 Iranian taxa of Nepeta (Lamiaceae) was conducted using scanning electron microscopy (SEM). Dierences in surface ornamentation, size, shape and color were observed between the species. e studied taxa were categorized in two basic types based on surface ornamentation: non-sculptured (smooth-type) and sculptured nutlets. e non-sculptured nutlets type could be further divided into four sub-types, including smooth, granulate, undulate-cellular and reticulate. In the sculptured nutlets, three subtypes of tuberculate, tuberculate-cellular and verrucate were recognized. e shape of nutlets were described as oblong, ovoid-oblong, oblong-linear, to elliptic-oblong and their size range are 1.2–2.0mm in length and 0.5–2.0 mm in width. Based on micrographs, the areole form and location were dened as bi-lobed, straight, basal, sub-basal or lateral. Nutlet micromorphological characteristics such as surface ornamentation can be useful for classication and identication of e.g. medicinal species of Nepeta in Iran.

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