162 



parations I hâve never been able tôt discover anything 

 that resembled root-formation. The sprout-carrying leaves 

 which had been planted in wet sand did not form roots 

 either. As far as I know formation of adventitious roots 

 does not occur at ail with Gneium G-nemon, 



A connection between the vascular System of an adven- 

 titious sprout and the nerve System of the mother leaf is 

 established by procambial bundles, formed by cells ofthe 

 tissue situated between the meristem and a leaf bundle. 



As a rule we find as the first indication of this vascu- 

 lar bundle connection in the immédiate vicinity of very 

 young meristems even, some tracheids and cells, changing 

 into them (PI. III. fig. 15). The degree of development, 

 reached at a certain moment by this vascular bundle con- 

 nection, is not directly dépendent on the degree of develop- 

 ment of the adventitious bud in question, but seems to 

 me to stand in close relation to the distance between meri- 

 stem and leaf bundle and to the diameter of this latter 

 (cf. figs. 17, 18, 19, 20). When a complète connection has 

 been established we see the vascular bundles of the adven- 

 titious sprout within the knob in which the bud has 

 formed, bend towards each other and unité with a more 

 or less cylindrical group of of locally formed vessels and 

 tracheids, the ramifications of which are connected with 

 the vascular bundles of the mother leaf (PI. IV, fig. 22). 



When describing the changes, macroscopically observed 

 with a leaf in which adventitious buds are forming, it 

 has already been briefly stated that the yellow vesicles 

 initiating the process of budformation, are caused by a 

 scale-insect, Aspidiotus dictyospermi Morg.. 



By médiation of Professer Cockerell of the University 

 of Colorado in Boulder, U. S. A., the insect has been 

 determined for me at the U. S. Department of Agri- 

 culture, Bureau of Entomology, in Washington. 

 Hence I got the following information: „The scale insect 



