Comparative morphology, anatomy and palynological studies of perennial species of Onobrychis (Fabaceae) in northeast Iran

This study examined morphological, anatomical and palynological characters for six species, two subspecies and two varieties of perennial Onobrychis growing in northeast Iran. In the morphological study, shape, size and color of vegetative organs and legumes were assessed. For the anatomical study, cross sections of mature fresh or dried stems, leaflets and petioles were prepared and stained. In the palynological study, pollen were extracted, acetolysed and observed by SEM. The morphological study indicated that some characteristics varied among species, such as shape of stipules and calyx teeth, color and shape of corolla segments and legumes and an identification key is provided based on these characters. Also, in internal structure some differences were noticed in the shape of petiole cross sections, the thickness of cortex and pith shape in petioles and the arrangement of vessels in stems. Some anatomical characters proved useful to identify species, but not sections. Palynological results showed circular and obtuse triangular pollen in polar view and elliptical pollen in equatorial view with reticulate ornamentation. In addition, a cluster analysis was done based on morphological, anatomical and palynological features. The resulting dendrogram confirmed the taxonomic treatment suggested by Sirjaev and Rechinger.