Morphology of glands and trichomes of Matthiola W.T.Aiton species in the Flora Iranica area was examined using stereomicroscope and scanning electron microscope to evaluate their systematic significance and assess infrageneric relationships. The study demonstrated that the general features of the glands and trichomes were constant among different populations of a given species, but they exhibited useful variability in the delimitation of species and their grouping. Reliably diagnostic features include gland-stalk length; distribution of trichome types and glands on various organs; trichome and gland densities; and trichome rays number, length and thickness. Our results confirm the removal of Matthiola alyssifolia (DC.) Bornm. from the genus. The species was unique in the distribution of trichomes types and glands on various organs such as stems, pedicels, sepals, and leaves. Other important aspects include the presence vs. absence of glands and trichomes, distribution of simple and 2-4-rayed trichomes and glands on abaxial (vs both) leaf surfaces and leaf margin, and connation of gland stalks. Finally, based on the examination of type specimens and closer studies of trichomes, glands, and other morphological features Matthiola graminea Rech.f. is reduced to synonymy of Matthiola ghorana Rech.f.
Cruciferae, Matthiola, indumentum, trichome