TERATOLOGY IN MODERN BOTANY. 85 



that malformations may be hereditarily transmitted, that is 

 to say, they may proceed from internal causes with which 

 we are unacquainted. Instances of the latter kind have been 

 partially known for a long time. It is a matter of common 

 knowledge that the doubling of flowers may be perpetuated 

 by seed, as may also the remarkable appearance of peloria 

 in many plants (see Darwin, Variation of Aiiujials and 

 Plants), and even that in some cases constant races have 

 been obtained which always produce certain malformations. 

 This is the case in Celosia cristata, the well-known Cocks- 

 comb. In the plants with which I experimented, my 

 experience was opposed to that of other authors, for I found 

 that the transmissibility of the fasciation by heredity is 

 absolute. Even when I cultivated the plants in sterile 

 sand, they always exhibited this phenomenon, even in the 

 second generation. 



Transmissibility by heredity, at any rate partial, may be 

 assumed for all such malformations as arise spontaneously. 

 Evidence in favour of this is afforded by the investigations 

 of De Vries. 



I. Fasciation} — De Vries was able to demonstrate the 

 hereditary transmissibility of fasciation in eight plants, 

 though it was never so absolute as to be exhibited by every 

 individual, but still the fact that it did occur was plainly 

 shown. As an example may be taken Crcpis biennis, in 

 which fasciation was shown in the radical inflorescences 



in the second generation in - - 30 per cent, 



in the third generation in - - - 40 per cent, 



in thefourth generation in - - - 30 per cent. 



in the fifth generation in - - - 24 per cent. 



Sometimes, too, a generation may be missed. Thus the 

 seed from two fasciated flower- heads of Taraxacum 

 officinale when sown gave, in the first year, only normal 

 individuals, but in the second year the same plants showed 

 ten fasciated inflorescences, and this increased to about 30 

 per cent, in later generations. External influences are 



^ De Vries, "Over de erfeligskheid der fasciatien," Botan. /aarb., 

 Dodonala, 6, Jaarg., 1894, with resume in French. 



