420 De Vries . — On Biastrepsis. 
I have for some years adopted the latter method ; it is more 
convenient, and it is more certain, especially when the spring 
is dry. 
6. Good, loose soil, well manured with nitrogenous matter, 
is an important essential. On unmanured sandy soil it is 
impossible to raise, even from the best seed, any twisted 
individuals ; if the soil is hard or unfertile, the percentage of 
such individuals diminishes. 
7. It is possible to contract the life-history of Dipsacus 
sylvestris torsus into the limits of one year, if the seed be 
sown immediately it is ripe and the conditions be favourable. 
By this means an additional generation can be obtained each 
year ; and it might perhaps be possible, by selection, to 
produce an annual twisted breed. However, so far as experi- 
ment goes at present, it appears that the annual character is 
developed at the expense of the biastrepsis ; for in such plants 
there is little or no twisting of the stem. 
8. The statement that, with a given hereditary tendency, 
a monstrosity becomes more marked the more favourable the 
conditions of life, and therefore the more vigorous the growth, 
is true not only for the biastrepsis of Dipsacus sylvestris , but 
is established for the most various plants and different mon- 
strosities by the observations which I have made during the 
last ten years 1 . 
1 Vide, Ueber die Abhangigkeit der Fasciation vom Alter bei zweijahrigen 
Pflanzen, Botan, Centralblatt, Bd. lxxvii, 1899 ; and, Sur la culture des fasciations 
des especes annuelles et bisannuelles, Revue gdnerale de Botanique, Tom. xi, 1899, 
p. 136. 
I am always ready to supply seed of Dipsacus sylvestris torsus , even in consider- 
able quantity. I can generally supply specimens of twisted stems. 
