CYTOPLASMIC HEREDITY 415 



alike, fall into two categories: (1) those inherited according to ordinary 

 Mendelian rules, which is taken to mean that in such cases the processes 

 concerned in their development are under the influence of differential 

 nuclear factors; and (2) those not so inherited and therefore seeming to 

 have their differential basis in the cytoplasm. Both types may appear in 

 the same genus or species, e.g., in Zea Mays. It is to be emphasized 

 that the characters in both categories are developed under the influence 

 of both nucleus and cytoplasm, but that they differ with regard to the 

 location and nature of the factors acting differentially in the developing 

 system. Only the second category — the "non-Mendelian" chlorophyll 

 characters — will be considered in the following classification of the 

 best known cases. ^ 



1. The Inheritance Is Maternal. — a. The variegated plants when 

 selfed or crossed produce variegated, green, pale-green, and white 

 offspring. 



The classic example of this type is Mirabilis jalapa albomaculata, 

 described by Correns (1909a). Plants of this race have some branches 

 with normal green leaves, some with white leaves, and some with varie- 

 gated leaves. Flowers are borne on branches of all three types. Crosses 

 between unlikes result in seedlings with the color of the maternal parent. 

 For instance, if a flower on a green branch is pollinated with pollen from 

 a flower on a white branch, the offspring are all green. In the reciprocal 

 cross the offspring are all white and soon die because of the lack of chloro- 

 phyll. If flowers on variegated branches are pollinated, offspring of all 

 types may result. In no case does the pollen affect the color of the 

 progeny.^ 



b. The variegated plants produce only variegated progeny, irrespec- 

 tive of the type of pollen used: Humulus japonicus albomaculata (Winge, 

 1919a). 



c. The affected plants produce only self-colored (green or pale-green) 

 progeny: Glycine hispida (Terao, 1918). 



2. The Inheritance Is Biparental. — Crosses between flowers on the 

 green and the white parts of the variegated plant may result in green, 

 white and variegated offspring; selfing variegateds results only in white 

 offspring. The type case in this class is Pelargonium zonale albomarginata 



2 This classification was drawn up by Demerec (unpubl.)- See also Winge (1919o) 

 and the recent reviews by Correns (19286) and Chittenden (1927o). For ferns, see 

 Andersson-Kotto (1931). Kiister (1927) describes the anatomy of variegated leaves. 

 The relation of chlorophyll inheritance and other genetic phenomena to pathology is 

 discussed by Link (1932). 



3 Other cases: Stellaria, Senecio, Taraxacum, Hieracium, Arabis, and Meseynbry- 

 anthemum (Correns, 1919, 1922, 19286, 1931); Antirrhinum (Baur, 1907, 1910); 

 Melandrium (G. H. ShuU, XQIZ); Primula (Gregory, 1915); Zea Mays (E. G. Anderson, 

 1923; Demerec, 1927); Viola (J. Clausen, 1927), Oryza (Kondo, Takeda, and Fujimoto, 

 1927); and Sorghum (Karper and Conner, 1931). 



