302 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Pericarp. The walls of the fruit; the matured ovary wall. 



Perigynium. The membranous, often inflated Bac inclosing the ovary or achene in 



the genus Carex. 

 Persistent. Referring to organs which after the growing period remain attached to the 



parts bearing them. 

 Petal. A division of the corolla. 

 Petaliferous. Bearing petals. 

 P etiolate. Furnished with a petiole. 



Petiole. The stalk by which the blade of a leaf is attached to the stem. 

 Pilose. Provided with soft hairs. 



Pinna. A primary division of a pinnately compound frond or leaf; leaflet. 

 Pinnate. Referring to compound leaves, with the segments or leaflets arranged on 



each side of a common axis. 

 Pinnatifid. Pinnately lobed or cleft to tho middle or beyond. 

 Pinnule. A division of a pinna; a secondary pinna. 

 Pistil. The seed-producing organ of a flower, consisting of ovary, style, and stigma 



(or the style wanting). 

 Pistillate. Referring to flowers which are provided with pistils but not with stamens, 



and to individual inflorescences and plants having only pistillate flowers. 

 Pitted. Having numerous small depressions. 

 Placenta. Any ovule-bearing part of the ovary. 

 Plaited. Same as plicate. 



Plano-convex. Flat on one side and convex on the other. 

 Plicate. Folded into regular elongate plaits, like a fan. 

 Plumose. Feather-like, with fine hairs on each side. 

 Plumule. The bud of the embryo. 



Pod. The popular name for a dry dehiscent fruit, especially a legume. 

 Pollen. The fecundating granules developed within the anther. 

 Polygamous. Bearing both perfect and imperfect flowers. 

 Polypetalous. Having the petals distinct from each other. 

 Pome. The fleshy fruit of the apple family. 

 Prickle. A stiff sharp-pointed emergence. 



Procumbent. Trailing or lying on the ground, but without rooting at the nodes. 

 Proliferous. Reproducing vegetatively by buds, bulblets, or offshoots. 

 Prostrate. Lying flat upon the ground. 

 Prothallium. The inconspicuous sexual stage of the Pteridophyta, giving rise to the 



spore-bearing plant known as a fern or fern ally. 

 Puberulent. Very finely pubescent. 

 Pubescent. Covered with short hairs. 



Punctate. Dotted with small depressions or translucent glands. 

 Pungent. Ending in a sharp stiff point. 

 Quadrate. Nearly square in form. 

 Raceme. A form of inflorescence in which the pediceled flowers are borne upon au 



elongate axis. 

 Racemose. In racemes, or resembling a raceme. 

 Rachilla, A little rachis or axis, applied especially to the axis of the spikelet of 



grasses. 

 Rachis. The axis of a compound leaf or of an inflorescence. 

 Radiate. Spreading from a common center; bearing ray flowers. 

 Radical. Arising from the root or the base of the stem. 

 Radicle. The rudimentary stem of the embryo below the cotyledons; called also 



hypocotyl or caulicle. 

 Ray. The branch of an umbel ; the marginal flowers of an inflorescence in composites 



when different from those of the disk. 



