TERATOLOGY IN MODERN BOTANY. 91 



indeed the fact has already been referred to, that in a 

 number of plants, c.o-., Digitalis purpurea, the tendency 

 to the formation of peloria is transmissible by seed, and 

 Peyritsch relates a similar case in Leonurus cardiaca 

 amonor the Labiatas. In Galiobdolon and Lajiiiuni, how- 

 ever, the tendency (which must be here regarded as a 

 latent disposition) to the formation of peloria only shows 

 itself when special conditions of life call it forth. In this 

 connection an example may be mentioned which does not 

 indeed belong strictly to teratology, but which shows that 

 there may be present in a plant two different organ-forming 

 tendencies, of which the one is in a latent condition at a 

 certain stage in the life-history of the plant, but may be 

 brought into action by the operation of external factors. 

 Many swamp-loving monocotyledons first produce lanceolate 

 primary leaves/ whilst later they bear more highly developed 

 leaves with stalks and blades. A plant of Sagittaria iiatans 

 or Eichhornia azurca may, however, be compelled to repeat 

 the formation of the simple leaf by merely placing it under 

 unfavourable conditions, by cutting the roots, for example, 

 or by immersing them in distilled water. The power to 

 form these early simple leaves is thus proved to have been 

 still latent, and although the plant had long been producing 

 other leaves, stimulus from without brought this power into 

 activity again. 



In a similar way we can explain the fact that fasciation 

 may be artificially produced by causing the sap to pass 

 rapidly and with increased intensity into a lateral bud which 

 would normally receive but a small quantity of nutriment 

 may be readily produced in some annual plants {Pkascolus 

 multiflortis, P^icia Faba) by cutting off the main axis above 

 the cotyledons. The axillary buds frequently then become 

 fasciated instead of developing normally. In the same way 

 I was able to cause the simple primary leaves of Vicia 

 Faba to develop into foliage leaves, or into such intermediate 

 forms between foliage and primary leaves as any teratologist 

 would recognise as malformations, and in experiments in- 



^ See Goebe!, F/lajizetiluo/. Schilderufigen, vol. ii. 



