410 De Vries.— On Biastrepsis in its 
breed can easily be raised. Under these circumstances the 
question arises, What would be the effect of sowing the seed, 
not in the spring, but in summer or in autumn ? and I have 
endeavoured to find an answer to this question by the experi- 
ments of which the following is an account. 
Seeds were sown in the summers of 1892 and 1893, at the 
beginning of June, at the end of July, and in the middle of 
August. The seed used belonged to the fourth or fifth 
generation of my breed which had already attained 34 per 
cent, of twisted main stems. The chief result was that the 
plants obtained by summer-sowing regularly developed their 
shoots in the following year ; but, with the exception of 
a single individual of the June sowing, the stems were not 
twisted. The details of the various cultures are as follows : — - 
Sowing of June 1, 1893. The seed was that of 1892, from 
a crop which contained 34 per cent, of twisted stems ; it was 
sown in rows on the bed. The seedlings came up regularly ; 
and up to October superfluous plants were weeded out so 
soon as they began to touch one another. About twenty 
plants per square metre remained, so that the condition of 
space was very favourable (see p. 404) ; there were 179 plants 
in 9 square metres. In May, 1894, all the rosettes shot up 
without a single exception. As soon as the phyllotaxis of the 
shoot could be made out, the plants were examined. One 
stem was found to be characteristically twisted, another had 
three-leaved whorls, whilst all the others had the normal 
decussate phyllotaxis and showed no twisting of the stem. 
All the plants, with the exception of the twisted individual, 
were dug up. This plant clearly showed itself, in the course 
of the summer, to be less vigorous than the twisted individuals 
of a normal culture, and it flowered later. Its stem was 
twisted right up to the inflorescence. 
Solving of July 28, 1892. Seeds harvested in 1891 were 
sown on a bed having an area of 4 square metres, and the 
soil was kept moist by means of a lawn-sprinkler. The seeds 
germinated rapidly, and before the autumn had formed 
vigorous rosettes of radical leaves. By the end of the follow- 
