femora

n. in insects, the largest of the leg segments; plural of femur

filament

n. the stalk of the stamen

filiform

a. thread-like

floret

n. a small individual flower of a cluster, as in the head of the Asteraceae or the spikelet of the Poaceae

frass

n. insect excrement, particularly of larvae

frond

n. in ferns, the leaflike structure and often the only portion of the fern growing above ground