ETIOLOGY OF MALFORMATIONS 185 



according to Hunger 1 , who has observed that when the plants are 

 cultivated in pots these vegetative shoots are suppressed. This however 

 may be the case only when the pot-plants are grown under unfavourable 

 conditions. In viviparous plants of Poa alpina, which I have grown in 

 pots for four years, the vegetative shoots have always appeared. Hunger's 

 observation however is quite in conformity with the facts which have 

 been cited above with regard to reversion to the juvenile form 2 . The 

 formation of flowers must be considered phylogenetically as the older, 

 the buds as having arisen somewhat later ; both ' tendencies ' are obviously 

 connected with different external conditions, and the plants which produce 

 flowers only are ' reversions ' to the original type. Such reversions are also 

 found elsewhere and are of special interest because, like the reversions to 

 the juvenile form, they obviously ensue if the vegetation of the abnormally 

 changed plant is subjected to conditions which are less favourable for it. 

 Thus Lowe states 3 that plants of the varieties of Polypodium vulgare 

 and Scolopendrium vulgare, which are known respectively as ' cambricum ' 

 and ' crispum,' and which possess a form of leaf different from the type, 

 if planted in poor soil revert after a few years to the normal form, but 

 do not lose their capacity to produce again the ' malformation V In other 

 examples however this is obviously not the case ; they retain even in 

 the most favourable soil their normal form, and the luxuriant nutrition 

 acts not as a factor causing the appearance of the malformation, but 

 purely as one which sets it free 5 . A few examples of the inheritance 

 of malformations are given in the following paragraphs : 



i. Fasciation 6 . De Vries has established the inheritance of fasciation in 

 eight plants. It is true that this is not so absolute that all the individuals show 

 it in the same way, but the fact of inheritance itself is sufficiently evident. As 

 an example Crepis biennis may be cited in which the fasciation appeared so 

 early as in the basal rosette : 



in the second generation in 3% 

 third 40% 



,. fourth 30% 



fifth 24% 



1 Hunger, Uber einige vivipare Pflanzen und die Erscheinung der Apogamie bei denselben. Dis- 

 sertation. Rostock, 1887. 



2 See page 171. 



3 Lowe, Fern-growing, p. 30. 



* The term 'malformation' is lightly applied to them because they are usually sterile. As to 

 the appearance of normal reversion-shoots in abnormal Cacteae see Fig. 5 in my 'Pflanzenbiologische 

 Schilderungen,' i. 



' With regard to double flowers see Goebel, Beitrage zur Kenntniss gefiillter Bliiten, in Pringsh. 

 Jahrb. xvii. 



6 De Vries, Over de erfelijkkeid der fasciatie'n, in Botanisk Jaarboek, Dodonaea, vi (1894), with 

 a French resume; id., Sur les courbes Galtoniennes des monstruosites, in Bulletin scientifique de 

 la France et de la Belgique, xxvii (1895). 



