_Piliferous_, bearing a slender bristle or hair (_pilum_), or beset with hairs. _Pilose_, hairy; clothed with soft slender hairs. _Pinna_, a primary division with its leaflets of a bipinnate or tripinnate leaf. _Pinnule_, a secondary division of a bipinnate or tripinnate leaf, 66. _Pinnate_ (leaf), when leaflets are arranged along the sides of a common petiole, 57. _Pinnately lobed_, _cleft_, _parted_, _divided_, _veined_, 56. _Pinnatifid_, _Pinnatisect_, same as pinnately cleft and pinnately parted, 56. _Pisiform_, pea-shaped. _Pistil_, the seed-bearing organ of the flower, 14, 80, 105. _Pistillate_, having a pistil, 85. _Pistillidium_, the body which in Mosses answers to the pistil, 159, 164. _Pitchers_, 64. _Pith_, the cellular centre of an exogenous stem, 138. _Placenta_, the surface or part of the ovary to which the ovules are attached, 107. _Placentiform_, nearly same as quoit-shaped. _Plaited_ (in the bud), or _Plicate_, folded, 72, 98. _Platy-_, Greek for broad, in compounds, such as _Platyphyllous_, broad-leaved, &c. _Pleio-_, Greek for full or abounding, used in compounds, such as _Pleiopetalous_, of many petals, &c. _Plumbeus_, lead-colored. _Plumose_, feathery; when any slender body (such as a bristle of a pappus or a style) is beset with hairs along its sides, like the plume of a feather. _Plumule_, the bud or first shoot of a germinating plantlet above the cotyledons, 13. _Pluri-_, in composition, many or several; as _Plurifoliolate_, with several leaflets. _Pod_, specially a legume, 122; also may be applied to any sort of capsule. _Podium_, a footstalk or stipe, used only in Greek compounds, as (suffixed) _Leptopodus_, slender-stalked, or (prefixed) _Podocephalus_, with a stalked head, and in _Podosperm_, a seed stalk or funiculus. _Pogon_, Greek for beard, comes into various compounds. _Pointless_, destitute of any pointed tip, such as a _mucro_, _awn_, _acumination_, &c. _Pollen_, the fertilizing powder contained in the anther, 14, 80, 103. _Pollen-growth_, 117. _Polleniferous_, pollen-bearing. _Pollen-mass_, _Pollinium_, the united mass of pollen, 104, as in Milkweed and Orchis. _Pollicaris_, Latin for an inch long. _Pollination_, the application of pollen to the stigma, 114. _Poly-_, in compound words of Greek origin, same as _multi-_ in those of Latin origin viz. many, as _Polyadelphous_, stamens united by their filaments into several bundles, 100. _Polyandrous_, with numerous stamens (inserted on the receptacle), 100. _Polycarpic_, term used by DeCandolle in the sense of perennial. _Polycotyledonous_, having many (more than two) cotyledons, as Pines, 23. _Polygamous_, having some perfect and some unisexual flowers, 85. _Polygonal_, many-angled. _Polygynous_, with many pistils or styles, 105. _Polymerous_, formed of many parts of each set. _Polymorphous_, of several or varying forms. _Polypetalous_, when the petals are distinct or separate (whether few or many), 89.