| Name | Structure/ Category | Description |
|---|---|---|
| Follicle | [Fruits] {type} | A usually dry fruit, with one interior chamber or locule, and splitting open (dehiscing) lengthwise along a single line, as in milkweed (Asclepias). |
| Forbs | These are plants that produce flowers with conspicuous petals and/or sepals; the flowers of such plants are often showy and insect-pollinated. In contrast, grasses (Poaceae), sedges (Cyperaceae), and miscellaneous other plants are not forbs because their wind-pollinated flowers lack petals and sepals, or their petals and sepals are tiny and inconspicuous. Such wind-pollinated flowers are not very showy, although there are some exceptions. | |
| Four-angled | [Leaf cross section] {shape} | More or less diamond-shaped in cross section. |
| Four-ranked | [Leaves] {habit} | With leaves arranged in along the stem in four rows. |
| Free-central | [Placentation] {type} | Attachment of ovules to a free-standing central axis in a compound ovary which has a single inner compartment (unilocular), and thus no interior partitions (septa). |
| Fruit | The seed-bearing structure in flowering plants, consisting of one or more matured or ripened pistil(s), along with any persisting accessory parts such as sepals or receptacle. | |
| Funnelform | A corolla that is shaped like a funnel, being narrow and tubular at the base, but flaring outward toward the outer margin. The corollas of Ipomoea spp. (Morning Glories) and Calystegia spp. (Bindweeds) are funnelform. | |
| Furrowed | [Bark of mature trunks] {surface appearance} | Bark with relatively long narrow depressions or grooves, as in tulip-tree (Liriodendron tulipifera). |
| Fusiform | [Buds] {shape} | Elongate, broadest at the middle, evenly tapering to either end, and rounded in cross section; spindle-shaped. |
| Fusion | The physical connection of equivalent or dissimilar structures, as fused sepals or petals. |
