184 SIGNIFICANCE OF MALFORMATIONS IN ORGANOGRAPHY 



II. 

 ETIOLOGY OF MALFORMATIONS 1 



The answer to the question what is the cause of malformations is beset 

 with serious difficulty, inasmuch as we recognize that they can be called 

 forth by external influences, whilst examples accumulate to show that 

 malformations are also hereditary and the result of internal unknown 

 causes 2 . Examples of the latter class have been longest known. 



It is common knowledge that ' double ' flowers as well as the 

 remarkable peloria of many plants are transmissible by seeds. Godron 3 

 found that the peloria in Corydalis solida were transmitted through five 

 generations, and other examples are given by Darwin 4 . Celosia cristata, 

 the well-known cockscomb, behaves in a like manner ; I found, in 

 opposition to the statements of other authors, that the transmission of 

 the fasciation is absolute, and that it appears even in plants cultivated 

 in sterile sand, and in the second generation too. 



A. All malformations which appear spontaneously, that is to say, which 

 are not caused by external factors, can be at least partly transmitted 5 . 



The degree to which this takes place varies. For example, only one- 

 third of the seedlings of Acer striatum with variegated leaves inherited 

 the variegation G . The investigations of De Vries have in recent times 

 furnished numerous proofs of the transmission by inheritance of mal- 

 formations. This inheritance is in some cases connected with special 

 external conditions, but in other cases it appears as the normal formation 

 of organs. In the ' viviparous ' species of Poa and of other grasses, the 

 formation of flowers and seeds in the spikelets is reduced to a greater 

 or less extent, and is replaced by the growth of the axis of the spikelet 

 into leafy shoots which subsequently fall off. The plants which arise 

 from these shoots repeat the ' malformation,' which is here one of great 

 use to the plant as it provides for propagation in the absence of formation 

 of seed. But this transmission does not take place in all circumstances 



1 See Goebel, Teratology in modern Botany, in Science Progress, 1896. 



3 It will be shown presently that malformations induced by external causes are often merely the 

 awakening of latent predispositions. 



3 Godron, in Memoires de 1'Acaclemie de Stanislaus, 1873. 



* Darwin, Variation of animals and plants under domestication. 



5 Lowe makes the remarkable statement regarding ferns ' Spores gathered from an abnormal 

 portion of a frond can reproduce this abnormality, whilst spores from a normal portion of the same 

 frond can produce normal plants.' See his ' Fern-growing,' p. 26, Other authors contest this. 



6 Regarding this and other cases see Godron, Des races vegetales qui doivent leur origine a une 

 monstruosite. Nancy, 1873 (Extract from the Memoires de 1'Academie de Stanislaus, 1873). 



