"Benno Bös" schreef in
Ornithogalum caudatum:
http://www.giftpflanzen.com/ornithogalum_caudatum.html

False Sea Onion

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That won't be it. Look at the toothed leaf margins in Ornithogalum caudatum
as compared to the leaf margins in the question plant.

It may be pretty difficult to identify this plant from a bulb: monocot bulbs
tend to look alike.
PvR