Knight — 70 — Dictionary 



capable of transmitting its distinctive traits to its offspring. 

 (iii) The derivation of a living thing from something unlike 

 itself. 



Heterogenetic Association. — The pairing, in an allotetra- 

 ploid, of chromosomes derived from different ancestral stocks. 



Heterogenetic Pairing. — Pairing and subsequent segrega- 

 tion between chromosomes derived from the two parental 

 species of an allopolyploid. 



Heterogenic Growth. — The growth of two parts, or organs, 

 at different rates which, however, keep a constant ratio to 

 each other. 



Heterogony. — (i) Reproduction by parthenogenesis as well 

 as by sexual means, (ii) The state of having heterogonic 

 growth. 



Heterogynism. — Having the female of a species showing a 

 more marked geographic variation than the male. 



Heterokaryosis. — The presence of genetically different nuclei 

 within individual cells of a mycelium (E. Sansome). 



Heterokaryotic Vigour. — Increased vigour comparable with 

 hybrid vigour but due to the presence together of two or more 

 genetically different types of nuclei in the mycelial cells. 



Heterokinesis. — The meiotic division during which gametes 

 of different sex-potentiality become separated by differential 

 distribution of the sex chromosomes. 



Heterolecithal. — Off eggs: having the yolk unevenly dis- 

 tributed. 



Heteromorphic. — Used of chromosome pairs the two mem- 

 bers of which differ in size or in shape. 



Heteromorphic Incompatibility. — Incompatibility (q.v.) 

 which is associated with, and dependent on, variation in floral 

 morphology (Mather). 



Heteromorphosis. — The production of an organ at a place 

 other than that in which it belongs; homoosis. 



Heteromorphcus. — (i) Atypical, (ii) Bearing two or more 

 kinds of flower on the one plant, (iii) Having more than 

 one form. 



Heterophytic. — Dioecious, q.v. 



Heteroplastic Graft. — A graft, or transplantation of tissue, 

 between different species or between different genera as op- 

 posed to a homeoplastic graft, q.v. See Xenoplastic Graft. 



Heteroploid. — Having a chromosome number which is not 

 an exact multiple of the basic haploid number; an individual 

 whose nuclei are of this type. 



