Bract

In this vegetable monster the bractes, or divisions of the spike, become wonderfully enlarged; and are converted into leaves.

A Verticil or Whirl may be[…]Naked; that is without involucre, bracte or brittle. Bracted - or Involucred

Great dense patches of them grew, four and five and six feet deep, impenetrable swathes of dark green bracts that advertised their danger.