_Pepo_, a fruit like the Melon and Cucumber, 119. _Perennial_, lasting from year to year, 38. _Perfect_ (flower), having both stamens and pistils, 81. _Perfoliate_, passing through the leaf, in appearance, 60. _Perforate_, pierced with holes, or with transparent dots resembling holes, as an Orange-leaf. _Peri-_, Greek for around; from which are such terms as _Perianth_, the leaves of the flower collectively, 79. _Pericarp_, the ripened ovary; the walls of the fruit, 117. _Pericarpic_, belonging to the pericarp. _Perigonium_, _Perigone_, same as _perianth_. _Perigynium_, bodies around the pistil; applied to the closed cup or bottle-shaped body (of bracts) which encloses the ovary of Sedges, and to the bristles, little scales, &c., of the flowers of some other Cyperaceæ. _Perigynous_, the petals and stamens borne on the calyx, 95, 99. _Peripheric_, around the outside, or periphery, of any organ. _Perisperm_, a name for the albumen of a seed. _Peristome_, the fringe of teeth to the spore-case of Mosses, 163. _Persistent_, remaining beyond the period when such parts commonly fall, as the leaves of evergreens, and the calyx of such flowers as persist during the growth of the fruit. _Personate_, masked; a bilabiate corolla with a _palate_ in the throat, 92. _Pertuse_, perforated with a hole or slit. _Perulate_, having scales (_Perulæ_), such as bud-scales. _Pes_, _pedis_, Latin for the foot or support, whence _Longipes_, long-stalked, &c. _Petal_, a leaf of the corolla, 14, 79. _Petalody_, metamorphosis of stamens, &c., into petals. _Petaloid_, _Petaline_, petal-like; resembling or colored like petals. _Petiole_, a footstalk of a leaf; a leaf-stalk, 49. _Petioled_, _Petiolate_, furnished with a petiole. _Petiolulate_, said of a leaflet when raised on its own partial leaf-stalk. _Petræus_, Latin for growing on rocks. _Phalanx_, _phalanges_, bundles of stamens. _Phænogamous_, or _Phanerogamous_, plants bearing flowers and producing seeds; same as Flowering Plants. _Phænogams_, _Phanerogams_, 10. _Phlœum_, Greek name for bark, whence _Endophlœum_, inner bark, &c. _Phœniceous_, deep red verging to scarlet. _Phycology_, the botany of Algæ. _Phyllocladia_, branches assuming the form and function of leaves. _Phyllodium_ (plural, _phyllodia_), a leaf where the seeming blade is a dilated petiole, as in New Holland Acacias, 61. _Phyllome_, foliar parts, those answering to leaves in their nature. _Phyllon_ (plural, _phylla_), Greek for leaf and leaves; used in many compound terms and names. _Phyllotaxis_, or _Phyllotaxy_, the arrangement of leaves on the stem, 67. _Physiological Botany_, 9. _Phytography_, relates to characterizing and describing plants. _Phyton_, or _Phytomer_, a name used to designate the pieces which by their repetition make up a plant, theoretically, viz. a joint of stem with its leaf or pair of leaves. _Pileus_ of a mushroom, 172.