| Name | Structure/ Category | Description |
|---|---|---|
| Pistillate | [Flowers] {gender} | Having functional pistils, but no functional stamens, making the flower unisexual and female. |
| Pith | The more or less soft and spongy tissue in the center of some stems and roots; sometimes degenerating to leave a hollow tube. | |
| Placentation | The arrangement of ovules within the ovary. | |
| Plane | [Leaf margins, Leaflet margins] {vertical disposition} | With midrib and margin all in one plane, or nearly so; flat. |
| Plated | [Bark of mature trunks] {surface appearance} | Bark with relatively large, more or less flat plates, as in mature loblolly pine (Pinus taeda) or mature white oak (Quercus alba). |
| Plumose | feathery, plume like. For example, wind-pollinated female flowers often have plumose stigmata so that they are more likely to receive the pollen of male flowers. Sometimes the hairs at the apex of a wind-dispersed achene (or seed) are called 'plumose' because they are branched and feathery in appearance, rather than straight and bristly | |
| Pollen | The small, often powdery, grains which contain the male reproductive cells of flowering plants and gymnosperms. | |
| Pollen cone | A male or pollen-producing cone; typically smaller and of shorter duration than seed cones. |
