APPENDIX I 



Pentaploid, v. Polyploid. 



Periclinal CraMAERA, V. Chimaera. 



Phenocopy, the phenotype of a given genotype changed by external 

 conditions to resemble the phenotype of a different genotype. 

 Goldschmidt 1938. 



Phenogenetics, Developmental Genetics. Haecker 1918. 



Phenotype, the kind or type of organism produced by the reaction of 

 a given Genotype with a given Environment. Johannscn 1909. 



Phylogeny, the evolutionary history of any related group of organisms. 



Pin and Thrum, v. Heterostyly. 



Plasmagene, a particle whose reproduction in the cell, but outside the 

 nucleus, and transmission by the egg (and sometimes by the pollen 

 or sperm) determines a likeness of daughter cells and individuals to 

 their parents. Cf. Virus. May be taken to include Plastogene. 

 Darlington 1939. 



Plasmon, the cytoplasm of an individual considered as a single hereditary 

 agent; the sum of the plasmagenes. Wettstein 1924. 



Plasmosome, Nucleolus. 



Plastid, a self-propagating body in the plant cytoplasm associated with 

 pigment production (chloroplast, chromoplast) or assumed to be 

 capable of being associated with it (leucoplast, proplastid). Schimper 

 1885. 

 Plastid Inheritance, v. Inheritance. 



Plastogene, a particle attached to a plastid whose reproduction deter- 

 mines a likeness of daughter to parent plastid. Cf. Plasmagene. 

 Imai 1937. 



Pleiotropy, the production of physiologically uncorrelated effects by 

 a mechanically unitary, i.e. single, gene. Ascribed to one gene 

 initiating two or more chains of reactions. Attributable to complete 

 linkage of two or more physiological units. Plate 1910. 

 False Pleiotropy, where the lack of correlation is spurious and the 

 various effects are traceable to one initial reaction chain. Griineberg 



1943- 

 P.M.C., Pollen Mother Cell. 

 Point Mutation, Gene Mutation. Bridges 1923. 

 Polar Bodies, the expelled products of the two divisions of the oocytes 



in animals. Robin 1862. 

 Polarization, i. Of chromosomes at telophase of mitosis and, later, the 



maintenance of their proximal parts on the polar side of the nucleus. 

 2. Of chromosomes at zygotene, the movements of their ends towards 



the part or parts of the nuclear surface where the centrosomcs lie. 



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