868 WEED FLORA OF IOWA 



Palmate. Radiately lobed or divided. 



Panicle. Loosely, irregularly branched raceme. 



Papilionaceous. Butterfly-shaped, like the corolla of the pea, etc. 



Papilla. A soft elongated projection. 



Papillate. Having papillae. 



Pappillose. Papillate. 



Pappus. The modified limb of the calyx in corn, in Composite, 

 especially, when the summit is developed in a feathery or plumose 

 manner. 



Parenchyma. All tissue composed of cells not having tapering 

 extremities; soft cellular tissue like that of pith. 



Parted. Cleft nearly or quite to the base. 



Pedicel. A branch of inflorescence supporting one or more 

 flowers. 



Peduncle. A flower-stalk. 



Perennial. Living more than two years. 



Perfect. Having both pistil and stamens. 



Perianth. The floral envelope including calyx and corolla (or 

 calyx alone when corolla is absent) whatever their form. 



Pericarp. The matured ovary. 



Perigynia, The bodies around the pistil. 



Perigynous. Parts around pistil. 



Persistent. Remaining longer than usual, as calyx upon fruit, 

 or leaves which die but remain on trees through the winter. 



Perisperm. The albumen of a seed. 



Petal. A division of the corolla. 



Petiole. The stalk of a leaf. 



Phloem. Portion of fibrovascular bundle containing the bast 

 and sieve tissues. 



Photosynthesis. Process by which sugar and starch are pro- 

 duced in a plant by means of the chlorophyll grain. 



Pilose. Covered with long soft hairs. 



Pinnate leaf. Compound with leaflets arranged on each side of 

 a common petiole. 



Pinnatifid. Pinnately cleft. 



Pistil. The central seed-bearing organ of the flower consisting 

 of ovary, style and stigma. 



Pistillate. Provided with pistils; properly, without stamens. 



Placenta. The part of the ovary to which the ovules are attached. 



Plumose. Like a feather, having fine hairs on each side, as in 

 the pappus-bristles of thistles. 



Pod. Any dry, dehiscent fruit. 



