330 
LOCK : STUDIES IN PLANT BREEDING 
The plants with smooth colourless testa had white flowers 
and no pigmentation in the axils. All the other plants 
showed the red-purple colour in these two regions. The 
ratio between plants with coloured flowers and those with 
white was 66 :20 or 3*3 :1. 
The plants with coloured flowers fell into two groups 
according to the colour of the testa. In both groups the 
grey colour was nearly the same, but one group showed in 
addition a flecking of well-marked purple spots, seen best in 
unripe seeds; in the other group these spots were absent or 
only represented by a few very faint blueish dots. Among 
the plants having coloured flowers the ratio between those 
with purple spots on the testa and those without was 50 : 16 
or 3'1: 1. 
It appeared further that flattened seeds of the type 
characteristic of “ French sugar ” were associated with wide 
pods and cubical or spherical seeds with narrow pods ; but 
the shape of the seeds and width of the pods varied so much 
in F 2 that this relation was difficult to ascertain exactly. 
It was quite clear that the dimpled character was associated 
with a coloured testa, whilst smooth seeds had always 
colourless testas. Coloured seeds with purple spots 
contained in distinctly wide pods in which a parchment 
layer was absent, exactly resembled the typical seeds of 
French sugar ; whilst white-coated seeds in narrow pods 
closely resemble the normal seeds of the native yellow pea, 
but were usually larger. Certain examples of both these 
forms came true to seed in F 3 . Nutrition also clearly 
plays a part in determining the shape of these seeds : 
starved seeds are usually smaller, flatter, and more dimpled 
than those upon strong and well-nourished plants. 
The above will serve to give an idea of the large number 
of factors upon which the shape of a pea seed can be shown 
to depend, apart from the cotyledon characters of strict 
wrinkling or smoothness. To return to the question of 
colour. It has been shown that the ratio of total coloured 
