1921] CURRENT LITERATURE III 
are certain types of chlorophyll inheritance. WuNGE‘ makes a hopeful attempt 
to classify all known cases of chlorophyll inheritance according to the following 
scheme: 
I. The characters are situated in the nucleus and show Mendelian segre- 
gation, self-colored ee usually being dominant. To this class belong the 
kn alniba, citrina, chlorina, variegata, and albomarginata forms of 
Melandrium, pye eral Pelargonium, Mirabilis, Urtica, Aquilegia, Lunaria 
(CorRENS, Baur, and others). The most complex case on record is one 
recently solved by LrnpstRoms in which the F, of a trihybrid gives the remark- 
able ratio of 36 green:9 virescent-white:7 yellow:12 white. 
II. The characters are situated elsewhere than in the nucleus and do not 
show Mendelian inheritance. This class is further split up in the following 
interesting way: (a) The characters are transmitted by the plastids them- 
selves. In this case plants which are endowed with both green and colorless 
plastids may, through the uneven distribution of plastids of the two types at 
cell division, give rise to pure green and pure white areas, really a ‘‘somatic 
segregation.” Such areas, through seed, will breed true to their local char- 
acter. There is one known case, the “mosaic” Pelargonium zonale of Baur, in 
which plastids evidently accompany the male nucleus at fertilization, for 
here inheritance is bi-parental. In all other known cases no plastids accom- 
pany the male nucleus, and inheritance is strictly maternal. In -this last 
group we find the albomaculata forms of Mirabilis (CoRRENS), Antirrhinum 
(Baur), and Primula (GREGORY). 
b) Thecharacters are situated in the cytoplaian. In this case no thorough- 
going ‘“‘somatic segregation” is possible. A ‘“‘hybrid” plant, combining the 
character for normal chlorophyll development with the alternative character 
for chlorophyll deficiency, will have these characters well diffused and inter- 
min; 
en distribution of these effective elements in the scan, resulting in 
; of “di 
the elements. Pure albinos or pure green individuals are never produced by 
these “hybrids.” Here too we find in one case, the albomaculata form of 
Capsella (IkENO), the male nucleus seems to be accompanied by some cyto- 
plasm, since the chlorophyll inheritance is bi-parental. In the only other 
case on record, the albomaculata of Humulus (WINGE), the male evidently 
contributes no cytoplasm, for inheritance is strictly maternal. 
This classification seems fairly satisfactory, but it involves some funda- 
mentally different conceptions from those of CoRRENS and Baur. Probably 
*Wince, O., On the non-Mendelian inheritance in variegated plants. Compt. 
Rend. Lab. Carlsberg 34:1~20. figs. 4. 1919. 
5 Linpstrom, E. W., Concerning the inheritance of green and yellow pigments 
in maize seedlings. Genpiics 6:QI-I10. 1921. 
