Papule. A nipple-like projection. 



Parallel-veined. Said of an organ in which the veins are so placed relative to one 



another that they approximate parallel lines. 

 Parietal placentation. Said of ovaries in which the seeds are borne on structures 



on the ovary wall, or on structures raised from the ovary wall (fig. 789). 

 Parted. Cleft to below the middle. 



Pectinate. Said of an organ which is cleft into divisions in such a way as to re- 

 semble a comb (fig. 786). 

 Pedicel. Stalk or stem of a flower in a flower cluster (fig. 788). 

 Peduncle. The stem of a solitary flower or the main stem of a flower cluster (fig. 



788). 

 Pellucid-punctate. Having translucent dots. 

 Peltate. Said of a plane structure that is attached at a point on its surface rather 



than on the margin, such as the leaf of the garden nasturtium, Tropaeolum 



(fig. 446) or Nelumbo. 

 Pendulous. Hanging. 

 Penicillate. Like a brush, such as the tuft of hairs on the style in certain vetches, 



or at the tip of the phyllaries in certain Compositae. 

 Pentamerous. With parts of fives, as a corolla of five petals. 

 Perdurant. Very long lasting. 

 Perennial. Living three or more seasons. 

 Perfect. Said of flowers that have both stamens and pistils. 



Perfoliate. Said of opposite or whorled bracts or leaves that are united into a col- 

 lar-like structure around the stem that bears them (fig. 787). 

 Perianth. The nonessential appendages of the flower situated outside the stamen 



whorl, and including both sepals and petals or other segments homologous with 



them. 

 Pericarp. The ovary wall as it matures in the fruit. 

 Perigynium. The sac or sheath enveloping the fruit in Carex and often appearing 



as though it were the ovary wall (fig. 264). 

 Perigynous. Said of flowers in which the perianth and stamens are inserted on the 



receptacle around the gynoecium, or of flowers in which the ovary is partly 



embedded in the receptacle, e.g., the flowers of cherries and plums. 

 Persistent. Said of an organ that remains attached after ceasing to perform its 



usual biological function. 

 Petal. A unit segment of the corolla presumed to be homologous with a leaf. 

 Petaloid. Having the form and structure and sometimes also the arrangement of 



petals. 

 Petiole. The stem or stalk of a leaf (fig. 787). 

 Petiolule. The stalk of a discrete segment of a compound leaf. 

 Phyllary. A bract of the involucre in the Compositae (fig. 741). 

 Phyllopodic. Having the lower leaves with well-developed blades. 

 Pilose. Having a vestiture or pubescence of scattered, long, slender, but not harsh, 



hairs (fig. 785). 

 Pilosulous. Finely pilose. 



Pinna (-ae). A leaflet or primary segment of a pinnately compound leaf. 

 Pinnate. Having a common elongate rachis or axis, with segments arranged either 



oppositely or alternately along either side (fig. 495). 

 Pinnately compound. Said of structures the lateral segments of which are discrete 



and arranged along a common axis (fig. 787). 

 Pinnatifid. Cleft in a pinnate manner. 



Pinnule. A secondary pinnately disposed part of a twice or more pinnately com- 

 pound leaf. 



1723 



