Feral — 57 — Fusion Nucleus 



may occasionally undergo a quantitative disintegration, with 

 the consequence that varieties are produced intermediate be- 

 tween the integral varieties from which they were derived." 

 cf. Step Allelomorphism. 



Fracture. — The breaking of a chromosome into a centric 

 portion and one or more acentric portions, which do not 

 rejoin. 



Fragmentation. — Division of a nucleus by fission; amitosis. 



Fraternal Twins. — Dizygotic individuals from a single birth ; 

 twins, each of which arose from a separate ovum. 



Freemartin. — An intersex caused by the action of the sex 

 hormones of a male twin on its twin female foetus as a result 

 of anastomosis of placental blood vessels. 



Fructification. — Production of fruit. 



Fusion Nucleus. — The product of the fusion of the two polar 

 nuclei. This, after fusing with a male nucleus, gives rise to 

 the endosperm. 



