Ricinus communis L. (Euphorbiaceae, Acalyphoideae) is a highly variable species known as the castor oil plant. This study aimed to describe R. communis using several methodologies, such as vegetative morphometry, leaf surface ultrastructure, soil analysis, and gas chromatography-mass spectrometry (GC-MS) analysis, to understand the diversity of this species. The morphological analysis revealed that some samples had purple stems while others were grayish-green. The purple-stemmed R. communis phenotype reflects the intra-specific diversity of the species. The multivariate analysis of 25 R. communis samples based on 34 vegetative morphometric characteristics revealed that they belonged to three main groups (morphotypes). Each group attained some specific characteristics discriminating it from the other groups. Selected samples from each group were investigated using SEM, soil analysis, and GC-MS. The performed GC-MS technique revealed that six major compounds were detected in the chromatograms of the studied samples. The highest percentages of n-Hexadecanoic acid and 9,12,15-Octadecatrienoic acid were recorded. Ricinus communis demonstrated adaptive growth capability, where plants inhabiting coastal sites are salt-sensitive, while inland plants are relatively drought-tolerant species. The intra-specific variation between R. communis morphotypes indicated the possibility of the direct and indirect use of these varieties in genetic improvement programs of the species.