220 



PRINCIPLES OF PLANT-TERATOLOGY. 



4 



Fig. 57. — Rhinanthus minor. 

 Shoot showing origin of 

 scattered (spiral) phyllo- 

 taxis by fusion of the two 

 leaves at some of the nodes. 



series above ; lie also cites it as 

 occurring in the branches of 

 mature plants, e\g. Weigelia, Galy- 

 canthus, and Acer dasycarjpum. 

 Steinheil describes a stem of 

 Salvia Verbenaca with alternate 

 leaves, which he ascribes to 

 fusion. The writer has himself 

 seen this in the yellow-rattle 

 (Rhinanthus minor) (fig. 57). 

 The same thing was figured by 

 Clos in Stachys maritima (fig. 

 58) ; in this case the alternate 

 leaves were forked, but his con- 

 clusion is that they are dividing 

 and attempting to revert to the 

 normal arrangement. 



In many of those cases in 

 which the two cotyledons fuse 

 to form a single organ, the pheno- 

 menon is the direct cause of the 

 alternate phyllotaxis of the 

 foliage-leaves on the shoot above, 

 where, according to the normal 

 character of the plant, they 

 should exhibit the opposite-de- 

 cussate arrangement. This has 

 occurred in Salvia amplexicaulis 

 and in Eremostaclnjs laciniata 

 (Labiatas). Velenovsky mentions 

 a seedling of Eucalyptus jjulveru- 

 lenta, in which one cotyledon 

 only was present, as a conse- 

 qu ence of which the foliage-leaves 

 above were alternately arranged. 

 It is possible that each leaf in 

 these cases represents a congeni- 

 tal fusion of two, so it is placed 

 under this heading. 



