What crucial difference separates wild onion leaves from toxic death camas leaves?

Wild onion leaves carry the essential garlic/onion smell, while death camas leaves do not smell like onions.

The most important factor in distinguishing the edible wild onion grass (*Allium vineale*) from the highly toxic look-alike, death camas (*Nothoscordum bivalve*), is the presence or absence of the characteristic allium odor. Wild onion leaves are known to carry that essential, unmistakable garlic or onion smell when crushed or handled. Conversely, the leaves of death camas completely lack this aromatic quality; they do not smell like onions or garlic at all. While there are secondary differences, such as wild onion leaves often featuring a U-shaped valley and being softer, and death camas leaves being more grass-like with a V-shaped notch, the scent remains the primary, non-negotiable determinant for safety prior to consumption.