ON BIASTREPSIS IN ITS RELATION TO CULTIVATION. 173 



Sowings in the summer or in the early autumn yield seedlings 

 which throw up shoots in the following year, which shoots show little 

 or no tendency towards biastrepsis. On the other hand, good results 

 are obtained from autumn-sowings, yielding plants which do not 

 throw up their shoots until the next summer but one and have 

 therefore a longer rosette-stage: the proportion of biastreptic plants 

 is in this case rather larger, if anything, than in the case of ordinary 

 spring-sowings. 



With regard to the spring-sowings it does not appear to be a 

 matter of great importance vv^hether the seed be sown in March, 

 in April or early in May; or whether the seed be sown directly in 

 the beds or in pans in the greenhouse, the seedlings being subse- 

 quently planted out. For various reasons 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 experiment 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 mon- 

 strosity 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 monstrosities by the observations 

 which I have made during the last ten years^). 



i) Vide, Ueber die Abhangigkeit der Fasciation vom Alter bei zwei- 

 iShrigen Pflanzen, Opera VI, p. 135; and, Sur la culture des fasciations 

 des esp^ces annue'les et bisannuelles, Opera VI, p. 1 06. 



I am always ready to supply seed of Pipsacus sylvestris torsus, even in 

 considerable quantity. I can generally supply specimens of twisted stems. 



(Annals of Botany, Vol. XIII, iSgg, p. 395.) 



