GENETICS: G. N. COLLINS 
347 
indicating the heterozygous nature of the half-tunicate parent plant. 
The tunicate plants were all half-tunicate, and no trace of the ramosa 
characters could be seen. 
Five self-pollinated first-generation ears were selected for planting 
in 1916. Three of these ears were tunicate and two normal. Four 
hundred and eight second-generation plants were matured in 1916 — 326 
from the three tunicate ears, and 82 from the two non-tunicate ears 
of the first generation. 
The progeny of the non-tunicate or normal Fi plants showed segre- 
gation into normal and ramosa in the ratio of 3 to 1 , the numbers being 
65 normal and 17 ramosa. In none of these plants was there evidence 
of tunicate characters. 
It was possible to classify the F2 plants descended from the tunicate 
Fi ears into (1) Normal, (2) Half -tunicate, (3) Full-tunicate, (4) 
Ramosa, and (5) Tunicate-ramosa. The last class comprised those 
plants in which both tunicate and ramosa characters could be recog- 
nized. When both the staminate and pistillate inflorescences were 
considered the classes were well marked. 
In the tunicate-ramosa group there were many plants with an en- 
tirely new type of inflorescence. In these the branching habit, which 
suggests that of the ramosa parent, was developed to a grotesque ex- 
treme. As soon as branches formed these again branched. This divi- 
sion continued until the end of the growing season when the tissue was 
still in an embryonic condition and nothing resembHng floral or foHar 
organs was formed. The result was a white succulent mass. This 
pecuHar formatioii occurred in both lateral and terminal inflorescences, 
though it was much more common in the former, and in terminal in- 
florescences it was usually confined to the basal branches. 
This type of inflorescence is similar, if not identical, with an abnor- 
mality discovered by Blaringhem in a strain of Zea tunicata^ and termed 
by him ^cauliflower.' 
It was found possible to account for the ratios by the assumption 
of relatively simple gametic composition. The tunicate character is 
represented by T and its recessive allelomorph, the normal condition, 
by T'. The recessive ramosa character is represented by R' and its 
dominant allelomorph, the normal condition by R. 
The observed numbers compared with the numbers expected in 
accordance with this gametic composition are given in the following 
table. 
