Knight — 6 — Dictionary 



Alternative Inheritance. — Allelomorphism; a relationship 

 between two or more factors such that they are of necessity 

 separated into sister gametes in germ-cell formation; the al- 

 ternative relationship shown by characters governed by such 

 allelomorphic factors. 



Altmann's Granules. — Mitochondria, q.v. 



Ambisporangiate. — Hermaphrodite (flowers). 



Ameiosis. — The replacement of normal meiosis by a single 

 nuclear division so that the chromosome number is not halved. 



Ament. — A unisexual, generally bracteate, spike of flowers; 

 a catkin. 



Amitosis. — The division of a nucleus by cleavage without 

 separation of daughter chromosomes, so that the latter are 

 not necessarily equally distributed between the daughter nuclei. 



Amixia. — Cross-sterility. 



Amixis. — The absence of any fertilization process by reason 

 of the absence of sexual differentiation. 



Amnion. — One of the foetal membranes. 



Amniotic Cavity. — The space between the foetus and the 

 amniotic membrane, which is typically filled with the amniotic 

 fluid. 



Amniotic Sac. — The embryo-sac, female gametophyte or 

 megaspore. 



Amphiapomict. — An organism which normally reproduces 

 both sexually and apomictically. 



Amphiaster, — The spindle and its two asters collectively. 



Amphibivalent. — An interchange ring of four chromosomes. 



Amphiblastic. — Having the bulk of the yolk in one hemis- 

 phere; telolecithal. 



Amphicarpous. — Producing two kinds of fruit. 



Amphidiploid. — The result of hybridization between two 

 plant species or genera where the chromosome set contributed 

 by each parent undergoes doubling and produces in the hybrid 

 a chromosome number which is the sum of the diploid numbers 

 of the two parent forms. 



Amphigenesis. — The fusion of gametes to form a zygote. 



Amphigony. — Reproduction in which two individuals parti- 

 cipate. 



Amphikaryon. — A nucleus containing two haploid sets of 

 chromosomes. 



Amphimict. — An individual which reproduces by amphimixis. 



Amphimictic Population. — A population with free crossing 

 and vital and fertile descendants. Equivalent to panmictic 

 population (Cain, 1944). 



