440 
Kidd and West . — The Role of the Seed-coat in 
immediately after removal from the parent, remained in a dormant con- 
dition or showed a long delay in germination. On the other hand, yellow- 
ripe seeds with the testa removed, or dried in the laboratory for twenty-four 
hours with the testa intact, germinated immediately (ioo per cent.), even 
more rapidly than a sample of the previous year’s seed used as a control. 
Green-ripe seeds sown after the removal of the testa germinated com- 
pletely (ioo per cent.), but after a delay of a few days. When sown with 
the testa on they mostly died, and in the case of the few seeds which did 
germinate, it was noticed that germination was 'always preceded by a change 
in the colour of the radicle from green to yellow. If dried for forty-eight 
hours before sowing practically all the seeds were killed. 
Table I. 
Germination of White Mustard Seeds at different stages of maturity. 
Lot A. Twenty yellow-ripe seeds gathered and removed from the siliquas 
on Sept. 8, 3918. Dried in the laboratory for one day. 
Lot B. Twenty yellow-ripe seeds gathered on Sept. 8 and removed from 
the siliquas on Sept. 9. Sown immediately (i. e. not dried). 
Lot C. Twenty green seeds gathered and removed from the siliquas on 
Sept. 8. Sown immediately (i. e. not dried). 
Lot D. Twenty green seeds gathered and removed from the siliquas on 
Sept. 8. Testas removed before sowing. 
All the seeds were sown on moist silica sand in a glass thermostat at 
20° C. 
16 . 
40 
45 
Germinations after : 
65 4 5 
7 
9 
12 ’ 
21 
hours. 
hours. 
hours. 
hours. 
days. 
days. 
days. 
days. 
days. 
days. 
Lot A 
1 
16 
18 
20 
■ — 
— 
— 
— 
— 
„ B 
0 
0 
4 
9 
10 
13 
T 3 
14 
15 
20 
„ c 
0 
0 
0 
0 
0 
1 
5 
8 
10 
14* 
„ D 
0 
0 
0 
0 
2 
3 
20 
— 
■ E9| 
— 
* The 6 ungerminated seeds were dead. 
Table II. 
G ermination of White Mustard Seeds at different stages of maturity . 
All the seeds were sown on moist silica sand in a thermostat at 20° C. 
Kind of Seed sown 
(sown on Sept. n). 
Green-ripe, testas off 
„ „ on 
Yellow- ripe, testas off 
} > >> on 
Dry mature seed ( 1 9 1 7) 
Yellow- ripe, dried in 
the laboratory air 
for 3 days 
* The nine ungerminated seeds were dead 
Number 
of Seeds 
18 
24 
Germinations after : 
41 65 5 
7 
10 
i 9 
sown. 
hours. 
hours. 
hours. hours. 
days. 
days. 
days. 
days t 
10 
0 
0 
0 0 
7 
10 
— 
— 
10 
0 
0 
0 0 
0 
0 
1 
1 * 
10 
9 
10 
— — 
— 
• ' p. 
- - 
— 
10 
0 
0 
3 5 
5 
6 
6 
7+ 
10 
0 
6 
10 — 
— 
— 
— 
— 
10 
3 
10 
— — 
— 
— 
— 
— 
The three ungerminated seeds were not dead. 
