The correct option is
A Lemma
Awn is a stiff bristle which especially grows from the flower of species of flowering plants belonging to family Fabaceae. The lemma is a part of spikelet which is lowermost of two chaff-like bracts enclosing the grass floret. It often bears long bristle known as awn which is an important characteristic of Poaceae. A lemma is usually interpreted as a bract.
So, the correct answer is 'Lemma'.