The flower literally resembles a hooded cloak, hence its common names of monkshood and helmet flower.
From the timesunion.com
He is dressed as a friar with a tonsure, sandals, a dark hooded cloak, and a rope around the waist.
From the en.wikipedia.org
I'll go out and buy a hooded cloak this afternoon.
From the en.wikipedia.org
Back inside the store, I have my eye on a jalaba, a hooded cloak worn widely here in the desert and suitable for wearing in both the hot sun and on cold nights.