F

F₁, F₂, etc.: Symbols used to designate the first generation, second generation, etc., after a cross.

Facultative: Occasional or incidental.

Falcate: Sickle-shaped.

Farinaceous: Containing starch or starch like materials.

Farinose: Covered with a meal-like powder.

Fasciation: A malformation of stems resulting in enlargement and flattening.

Fascicle: A cluster of flowers, leaves, etc., arising from the same point.

Ferruginous: Rust-coloured.  

Fertilization: Union of the gametes (egg and sperm) to form a zygote.

Filament: Thread; the stalk of a stamen supporting the anther.

Filiform: Slender; threadlike.

Fimbriate: Fringed.

Flabellate: Fanlike.

Flexuose: Zigzag; bent alternately in opposite directions.

Floccose: Covered with woolly hairs. 

Floret: Individual small flower, as in grasses and composites.

Foliaceous: Leaf-like.

Follicle: Dry dehiscent fruit composed of a single carpel.

Free: Neither adhering nor united.  

Fruit: The ripened ovary with adnate parts.

Frutescent, Fruticose: Shrubby.

Fugacious: Falling off early.

Funicle: The little cord which attaches the ovule to the placenta.

Furcate: Forked.

Fusiform: Spindle-shaped; tapering at each end from a swollen middle.