Anatomical Signatures in Fruits and Roots of Bunium and Elwendia (Apiaceae): Implications for Systematics and Adaptation

ABSTRACT Bunium and Elwendia include species such as Black Zira ( Elwendia persica , syn. Bunium persicum ), valued for their seeds and tuberous roots. We provide an anatomical assessment of fruits, seeds, and tuberous roots in four species— E. persica , E. cylindrica , E. caroides , and B. paucifolium —using microtomy, histochemistry, and morphometrics. Embryo size differed significantly ( p < 0.0001), ranging from 0.33 mm in B. paucifolium to 0.55–0.86 mm in Elwendia . B. paucifolium was monocotyledonous, whereas Elwendia species were polycotyledonous, with two to four cotyledons. During fruit maturation, vascular bundles expanded, while secretory canals widened and elongated, with the vascular‐to‐secretory ratio increasing from 0.40 to 0.56. E. persica had the largest secretory canals, whereas E. caroides had reduced canals and lignified vascular bundles. Tuberous roots exhibited radial architecture, with alternating canal‐rich and canal‐free cortical parenchyma. Larger roots developed additional apical buds and corresponding vascular systems, which progressively differentiated from small, weakly developed structures into distinct systems that converged with the main vascular system toward the lower root. Seeds stored lipids and proteins without detectable starch, whereas tuberous roots accumulated starch. These findings identify anatomical characters relevant to systematic differentiation and reveal functional organization of reproductive and storage organs.