Alium leaf. Light micrograph (LM) of a transverse section through the leaf (pinna) of a Allium. Allium is a genus of monocotyledonous flowering plants that includes hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. Monocot leaves are isobilateral in symmetry. In monocot leaf, the vascular bundle present parallel in each row. It has collateral and closed vascular bundles that are encased by both parenchymatous and sclerenchymatous bundle sheath. Magnification: x10 when printed at 10 centimetres wide.