Characterization of wild Onobrychis Mill. Subgenus Sisyrosema bunge (Fabaceae) germplasm resources from Iran using macro and micro-morphological traits

The genus Onobrychis Mill. is one of the most economically important members of the family Fabaceae, which has a complicated infrageneric tax-onomy. The genus has been traditionally divided into two subgenera, in which species of each subgenus have been classified in some sections. In the present study, the macro-and micro-morphological charac-teristics of legumes in three sections of the subgenus Sisyrosema were evaluated using scanning electron microscopy and light microscopy techniques. In total, 10 qualitative and quantitative traits were examined with 15 replicates per trait. PAST software and the multivariate statistical program were used for sta-tistical data analyses. All taxa have one-segmented legumes, and their dimensions significantly vary among the taxa. The legume's shape varied between elliptic, circular, semicircular, and reniform, however; the most common shape was detected as reniform. Additionally, fruit in half of the taxa had dorsi-ventral symmetry. The legume outline view was detected as plumose, smooth, and short hispid, with the plumose as the abundant form. The exocarp surface indumen-tum was observed as glabrous, plumose (the most frequently-occurring shape), tomentose, pilose, vil-lous, pubescent, puberulouse, plumose + villous, and short hispid + silky. The exocarp sculpturing pattern was observed as uni-formed reticulate (Afghanica and Heliobrychis) and hetero-formed reticulate (Hyme-nobrychis). In some cases, the taxa classification pattern did not follow species grouping in sections according to Flora Iranica. All the examined traits present a lack of taxonomic value at the section level. Among the characteristics, legumes shape and exo-carp sculpturing patterns can be considered as diag-nostic traits at the species level. However, the indu-mentum type, color, and shape of legumes, and their dorsi-ventral symmetry have limited taxonomic value at the infraspecific level. Our results support the non-monophyly hypothesis of these sections, however, the taxonomic level of some infraspecific taxa must be updated to species.