Astragalus cyclophyllos , is an herbaceous perennial plant of legominosae family which is very palatable to grazing animals and bees use its nectar to make honey. Rhubarb with the scientific name of Rheum ribes is another perennial plant of Iranian rangelands belonging to the polygonaceae family. Rheum ribes is a medical and edible plant of polygonacea family. The stem of Rheum ribes is believed to be a good laxative and its root extract is used to cure diabetes, stomach upsets, vomiting, smallpox, and measles. Its fresh petioles and stems are consumed as vegetables. It is also used in making jam, sweets, desserts, and pickles. The rang Astragalus cyclophyllos e is characterized as an vulnerable endangered species due to grazing while Rheum ribes is considered as a vulnerable lower risk species. Since cytogenetic studies on these two species have not yet been conducted, this study was carried out to study the chromosome characteristics of these two species and to prepare their Karyotype. Three accessions of Astragalus cyclophyllos were collected from Semirom, Fereidoonshahr and Bouinmiandasht. range Astragalus three accessions were collected of Rheum ribes from different regions of Isfahan and Qume proviances and cytogenetic studies were performed. The cytogenetic studies and analysis of mitotic, metaphasic chromosomes contained: seed germination, pretreatment of tissue samples, fixation of cellular and chromosomal structures, storage, hydrolyzation of samples, and chromosome staining. Samples were observed microscopically for chromosome number and morphology which led to the preparation of Karyotype and ideogram of the accessions. The results of the chromosome count showed that all the Astragalus cyclophyllos range Astragalus accessions were tetraploid with 32 chromosomes. .
