Alternating Annual and Biennial Habit. 301 
PLANTS PER PERCENTAGE OF PLANTS 
SQUARE METER WITH STEMS 
No. 1 1350 100 23 % 
" 2 and 3 630 + 650 50 43 " 
" 4 380 30 58 " 
That is to say, the closer the plants are together, and 
the less room each one has, as a result of this, for the 
unfolding of its leaves, the smaller is the number of 
annual plants. 
In the following year I repeated this experiment, but 
this time with the seeds of annual plants. The result 
was, however, the same. There were 1188 plants on one 
bed of 13 square meters, that is, about 90 per square 
meter; of these 20% were annuals. On the other bed 
of the same size there were 348 plants (or 27 per square 
meter) and 54% developed stems. 
I repeated the same experiment once more, in 1890, 
with the seeds of an annual plant of 1889. On the one 
bed there were 40 plants per square meter, of which 
17% were annual. On the control bed there were only 
ten plants in the same area, and of these 72% produced 
stems in the first summer; the extent of the bed in both 
cases was 5 square meters. 
In 1891 I investigated the influence of the distance 
between the plants in an experiment with Oenothera 
laei'ifolia, raised from the seeds of an annual race which 
had been selected for three generations. 1 The two beds 
were of the same size, had the same aspect and the same 
soil, and both received a similar and liberal dressing of 
guano. They were sown in the middle of May on the 
same day, but at the end of July they contained 195 
and 638 plants respectively (per each 6.5 square meters). 
As a result of this, the bed in which the plants were far 
1 See the pedigree in Vol. I, p. 224. 
