You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: DESIGN 
Clue: Derived from scutum, the Latin for "shield", it's a shield bearing a coat of arms, or a metal plate around a keyhole
escutcheon

Category: YOU GET AN "F" 
Clue: These seedless, nonflowering plants reproduce by spores on the undersides of their fronds
ferns

Category: OFF & RUNNING 
Clue: In 1985 this American middle-distance runner married discus thrower Richard Slaney

mary decker