Allium macrostemon

Family: Amaryllidaceae
English: Long-Stamen Onion
Japanese: ノビル(Nobiru)

This wild onion species grows in muddy soils near the coast. It reminds me a bit of the Chinese scallions we used to grow and pickle in our garden when I was growing up. Late spring is the best time for harvesting.

References:
新版　屋久島の植物 川原勝征,初島住彦(監修),2001：南方新社