ABSTRACT
This chapter describes the organographic construction of the common onion (Allium cepa) and compares it to that of garlic (Allium sativum) and leek and briefly to Japanese bunching onion, chives, Rakkyo, and Chinese chives. H. A. Jones and L. K. Mann provide good descriptions of the latter taxa. The chapter reviews the general development of the common onion and discusses the anatomy and development of the seed, stem, leaf, root, and inflorescence of Allium cepa. The onion vegetative axis is a rosette shoot with a short, squat stem due to the lack of internodal elongation. The vegetative stem is heart shaped in longitudinal section. Several morphological differences distinguish garlic from onion. Garlic has a dorsiventral, flattened leaf blade rather than a terete leaf blade. The inflorescence stalk of garlic is solid, not hollow. Onion stem anatomy and development have been studied by C. A. Hoffman, and by D. A. DeMason.
