APPENDIX I 



Hermaphroditism, the bearing of effective male and female gametes 

 by the same flower in Phanerogams, by the same prothallus in 

 Cryptogams and by the same individual in animals. Can be simul- 

 taneous or consecutive in animals. Sometimes incorrcctively used 

 for Intersexuahty. 



Heterocaryosis (fungi), the property of having cells with two or more 

 dissimilar nuclei. 



Heterochromatin, f. Chromatin. 



Heteroecy, I. Dioecy. Correns 1928. Subdivided by Hartmann 1918 into 

 Diplo-Heteroecy, Diploid dioecy and 

 Haplo-Heteroecy, Haploid dioecy. 



2. (fungi) having alternate unrelated hosts in different stages of the 

 life cycle. 



Hetero-Fertilization, the fertihzation of the endosperm- and embryo- 

 forming nuclei by gametes of different genetic constitution. 



Heterogametic Sex, producing gametes of two kinds in regard to 

 their properties of sex-determination. Heterozygous Sex. Wilson 

 1910. 



Heterogamy, the property by wliich male gametes of a hybrid transmit a 

 genotype or genotypes different from those of the female gametes. 

 V. Renner Effect. Applied to Complex Heterozygotes in Oenothera. 

 De Vries 1911. 



Heterogeneity, lack of agreement of different bodies of data in regard 

 to the value of one or more parameters of which they are all capable 

 of yielding estimates. The opposite of Homogeneit)'. 



Heterogenic, of i. a population, or 2. a gamete containing more than 

 one allelomorph of a particular gene or genes. Cf. Homogenic. 

 Fisher, cf. Lewis 1947. 



Heteromorphic Chromosomes, homologous chromosomes which are 

 different in size or form, especially at meiosis. Carothers 1917. 



Heteroploid, Aneuploid. Winkler 1916. 



Heteropycnosis, excessive charging of heterochromatin with nucleic 

 acid in meiotic and premeiotic divisions. Gutherz 1906. 

 Negative Heteropycnosis, deficient charging of heterochromatin 

 with nucleic acid in meiotic and premeiotic divisions. White 1936. 

 The nucleic acid starvation of Darlington and La Cour 1940. 



Heterosis, the property of a F^ hybrid of falling outside the range 

 dehmitcd by its parents in regard to one or more characters. Assumed 

 to be due to special combinations of dominant and recessive genes. 

 Usually applied to increase in vigour, when it may be termed 

 Hybrid Vigour. Cf. Transgressive Segregation. Shull 1911. 



395 



