Crook: the hook or recurved tip of the antenna in Hesperidae.
Observe the slender, stiff beak, terminating in two recurved points.
The feelers are recurved at the tip, and thickened just before the extremity.
Lobes of the leaves acuminate, often recurved; fruit ripens early.
The sori have indusia, but this is hidden by the margin of the pinnules, which are recurved.