GLOSSARY. 



343 



peduncle : the stalk or axis of an 

 entire inflorescence. 



pelvic : relating to the hip girdle, 

 e.g. pelvic fins of fishes. 



pendulous : drooping, e.g. many 

 catkins. 



penninerved : a type of leaf 

 having the veins arranged like 

 the barbs in a feather. 



perennial : persisting for three 

 or more years. 



perianth : the outer parts of a 

 flower, a term generally used 

 when calyx and corolla cannot 

 be separately distinguished. 



pericarp : the wall of the fruit. 

 It generally consists of three 

 layers epicarp, mesocarp, 

 endocarp. 



perigynous : a type of flower in 

 which the receptacle is flat or 

 cup-like, and the sepals, petals, 

 and stamens are placed apart 

 from the ovary. 



petals : the parts of the corolla 

 usually showily coloured. 



petiole : leaf -stalk. 



phenology : the study of the 

 periodic appearances of plants 

 and animals in relation to the 

 seasons. 



pinnae : the lobes into which 

 fern fronds are usually divided. 

 They may be simple or them- 

 selves divided into pinnules. 

 Also the external ear lobes of 

 mammals. 



pinnate : a type of leaf in which 

 the lobes or leaflets are ar- 

 ranged in serial pairs. 



pinnatifid : a type of leaf having 

 slight lobes cleft in series like 

 the parts of a feather. The 

 notches between the lobes 

 extend about halfway to the 

 midrib. 



pinnule : the lobes into which 

 the pinnae of fern fronds may 

 be cut. 



placenta : the part of a plant on 

 which the ovules develop. 



plumule : the young shoot which 

 emerges from the seed at ger- 

 mination. 



pod : a dry fruit, consisting of 

 a single carpel, which opens 

 along both ventral (seed-bear- 

 ing) and dorsal margins. 



pollen : the fertilising substance 

 of flowering plants. 



pollination : the application of 

 the pollen grains to the stigma. 



pome : a succulent fruit whose 

 fleshy part is formed from the 

 receptacle, e.g. Apple, Rowan. 



prickles : sharp spiny structures 

 arising from the epidermis of 

 plants. They do not contain 

 wood. Contrast spines. 



proboscis : a general term ap- 

 plied to the mouth parts col- 

 lectively of insects. 



procumbent : applied to stems 

 lying along the ground but not 

 rooting. 



prolegs: the temporary loco- 

 motor structures occurring 

 upon the hind body (abdomen) 

 or insects. 



proterandry : male elements 

 maturing before female. 



prothallus: the body which 

 bears the sexual organs in the 

 fern and allied plants. The 

 sexual generation. 



protogyny : female elements ma- 

 turing before male. 



pupa : the stage between larva 

 and imago in which meta- 

 morphosis in insects takes 

 place. It is of more general 

 significance than the term 

 chrysalis. 



raceme : an elongate inflores- 

 cence in which the flowers are 

 borne on simple stalks. 



