With plants of the kind we may compare the wonder-working moonwort (Botrychium lunaria), which was said to open locks and to unshoe horses that trod on it, a notion which Du Bartas thus mentions in his "Divine Weekes" – "Horses that, feeding on the grassy hills, Tread upon moonwort with their hollow heels, Though lately shod, at night go barefoot home, Their maister musing where their shoes become.