CONIFERS 



49 



branches, and occupy positions taken by dwarf-shoots on 

 vegetative branches. Above the spike-Uke inflorescence of 

 staminate flowers, a 66 65 



few foliaged dwarf- 

 branches are seen. 

 On older shoots, two 

 to three years old, 

 the spurs {n) or scars 

 of the fallen stamin- 

 ate flowers denote 

 the points at which 

 the latter were at- 

 tached. Thus a car- 

 pellary flower takes 

 the place of a lateral 

 long-shoot ; whereas 

 a staminate flower 

 replaces a vegetative 

 dwarf-shoot. 



Pollination and 

 its consequences. — 

 The flowers are pol- 

 linated by the agency 

 of the wind. When 

 ready for pollination 

 in May, the carpel- 

 lary cone stands 

 erect (c, cP). Its 

 axis (receptacle) 

 elongates, and thus 

 causes the carpels 

 to separate to a 

 slight extent. The 

 pollen-grains which 

 are blown against the 

 cones naturally reach the crevices between the carpels. They then 

 roll down the prominent rib of the placental scales, and thus meet 

 with the integuments of the ovules. The integuments curl up 

 slightly, and carry the pollen towards the top of the nucellus 

 — that is, towards the bottom of the micropyle-passage. In 

 the Pine, the pollen-grain itself reaches the micropyle, whereas 



Fig. 65.- 



67 68 



-Vertical section of carpellary flower of 

 Scotch Pine. 



Fig. 66.— Carpel of ditto. 



Fig. 67. — Carpel of fruit of ditto, with two' seeds {s) 

 having wings (h/) in contact with them. 



Fig. 68.' — Vertical section of seed of ditto :_ tf=endo- 

 sperm ; C£7^= cotyledons ; ^=:plumule; r=radicle; ?«= 

 micropyle. 



