GLOSSARY OF HOTANIC'AI. '1 KHMS 317 



Pedicel, tho stulk of a sin<i;l(' flower of an inflorosrciicc. 

 Peduncle, the stalk of an intlorL'sceiU'e or of a solitary flower. 

 Perennial, a plant which lives for more thin two years and 



does not perish after prodnein<; flowers and fruit, hut 



riowers again the succeeding season ; cf. liieiuiial and 



Annual. 

 Perianth, a floral envelope, not difrerentiated into two distinct 



series, calyx and corolla. 

 Pericarp, the wall of the ovary as developed in the fruit. 

 Perigynous, aj)plicd to flowers where the calvx tulx* surrounds, 



but does not enclose, the ovary. 

 Petal, a unit of the corolla, or inner series of a differentiatetl 



floral envelope. 

 Petiole, a leaf stalk. 

 Phanerogam, a Flowering Plant ; a wide temi, including the 



Gynuiospenns and Angiospernis. 

 Phyllotaxis, the plan of arrangement of the leaves on the 



stem. 

 Pistil = Gynaeceum (7.1'.). 

 Pollen, the yellow dust formed in the anthers of the stamens ; 



the male spores which produce the male gametes. 

 Pollen-grains = Pollen. 

 Pollen sac, the sporangium or sac in which the poUen-grains 



are formed in the anther. 

 Pollination, the act of dusting the stigmatic surface of the 



pistil with pollen. 

 Pollinium, the pollen mass of an Orchid (p. 138). 

 Polygamous, bearing hermaphrcKlite and unisexual flowers on 



the same or different individuals of the same s|Kiues. 

 Poljrpetalous, applied to flowers in which the |>etals are free 



from one another; cf. Gamopetalous. 

 Prickle, a pointed Emergence (7.1'.). 

 Protandry, the form of dichogamy, in which the male organs 



(andra^cium) mature before the female (gyna'ceum). 



