805 
Botany. -. “Variability of segregation in the hybrid’. By Dr. 
J. A. Honine. (Communicated by Prof. F. A. F. C. Went). 
(Communicated in the meeting of November 25, 1916.) 
Most botanists investigating heredity prefer to employ annual 
plants and endeavour to force biennials to flower in their first year 
in order to obtain seed, as was done by nearly all investigators 
of Oenothera. Perennials, to say nothing of trees, often require 
several years before their seedlings bloom, and sometimes they pro- 
duce but few seeds, so that their use has naturally been less in favour. 
The flowering season of annuals is brief, a few months only, 
and the seed obtained by self pollination of annual hybrids from 
different fruits is generally sown mixed, on the assumption that the 
segregation ratios are constant, so that for the ratios of the phaeno- 
types it does not matter much whether seed has been collected trom 
the first fruits or from those matured a month later. Probably this 
assumption is correct in many cases, perhaps in most, but not in 
all, as ZEDERBACER ') has shown for Pisum. 
There is no reason whatever to assume that Pisum is unique in 
this respect and further examples will doubtless be found. The best 
chance of finding clear cases will be, for annuals, among those 
with a long flowering season, and further among those perennials, 
of which one and the same individual can be studied for some years 
in succession. A tropical climate enabling one to collect seed almost 
throughout the year, would then be advantageous. 
In order to ascertain whether independent Mendelian segregation 
can take place simultaneously with respect to a number of factors, 
larger than that of the chromosomes, I crossed in 1913 a variety 
of Canna glauca with one of C. mdica. The number of genes in 
which these two differ was — and remains, unknown; it was 
certainly larger than three, the number of chromosomes in Canna 
indica according to Wriecanp *) and certainly larger than eight, the 
actual number of chromosomes, which was already indicated by 
KOERNICKE *), A brief description of the two species will make 
this clear. 
1) ZEDERBAUER, E., Zeitliche Verschiedenwertigkeit der Merkmale bei Pisum 
sativum. Ztschr. f, Pflanzenzüchtung I! p. 1—26, 1914. 
2) Bots Gaz: T: 30; 1900. ‘ 
3) Ber. d. d. bot. Ges. XXI. 1903, p. 66. See also Rec. d. trav. bot. \éerl. XII, 
1915, p. 28. 
