Polygenesis 



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Polytocous 



Polyphasy. — The existence of any sharply marked variations 

 of a species occurring within the same habitat (Ford). 



Polyphyletic. — The condition of a taxonomic group, usually 

 a genus or higher category, the members of which have not 

 come from the same phylogenetic stock. Polyphyletic groups 

 represent mistaken classification, according to most concepts, 

 because of convergent or parallel evolution (Cain, 1944). 



Polyphylogeny. — Lineage through several lines of descent. 



Polyphyly. — The state of being derived or descended from 

 several parent forms. 



Polyploid. — An organism whose somatic nuclei contain more 

 than two haploid chromosome sets. See Secondary Polyploid. 



Polyploid Complex. — A group of forms which contains 

 self-propagating secondary hybrids which have arisen from 

 crosses between auto- and allopolyploid forms. 



Polyploiding Agent. — A substance or treatment which, under 

 given circumstances, is capable of inducing polyploidy. The 

 following substances have been used successfully: Acenaph- 

 thene and various derivatives thereof; Apiol; Aurantia; 

 Colchicine; Diphenylamine ; Esters of naphthoic acid; Ethyl 

 mercuric chloride in conjunction with 1 :2 :5 :6-dibenzanthra- 

 cene; Naphthaleneacetic acid; Paradichlorbenzene ; Sanguin- 

 arine; Sulphanilamide ; Veratrine sulphate. 



Polyploidogenic Activity. — The capacity of a substance 

 (or ray, etc.) to induce polyploidy. 



Polyploidy, Partial. — The reduplication of small segments 

 of chromosome so that the organism is polyploid as regards the 

 reduplicated segments though normal as regards the remainder 

 of the chromosome complement. 



Polysepalous. — Having several distinct (separate) sepals. 



Polysomaty, — The production of somatic nuclei with multi- 

 ples of the normal somatic chromosome number. 



Polysomy. — (i) A condition in which some, but not all, of 

 the chromosomes in the set are present in the polyploid state, 

 (ii) Aneuploidy. N. Polysomic. 



Polysperm, Polyspermal, Polyspermous. — Many seeded; 

 having numerous seeds in the one pericarp. 



Polyspermy. — (i) The entry into the ovum of more than 

 one sperm, (ii) Multi-seeded state. 



Polysporous. — Having many spores, or seede. 



Polystemonous. — Polyandrous; having numerous stamens. 



Polytene Chromosomes. — Salivary gland chromosomes {q. 

 V.) m Dipt era. 



Polytocous. — Giving birth to several young at a time. 



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