Wild Onion

Allium triquetrum (also known as three-cornered leek, angled onion, onion weed, three-cornered garlic, and triangular stalked garlic) is a Mediterranean plant, but can also be found along the coasts of Oregon and California. Many parts of the plant are edible and taste somewhat like garlic or onion. The plant spreads rapidly and is locally common/invasive, particularly in disturbed areas.
A. triquetrum grows from an ovoid bulb with stems growing to 10–40 cm. Stems are sharply 3-angled, leading to the common name, three-cornered leek. Inflorescences are one-sided umbels with 3-15 flowers each. White flowers have green midveins.
Wikipedia