640 Vehicles of the Hereditary Characters. 
groups are regarded as units. Nevertheless, in some 
places, he has definitely expressed the view that every 
character which can vary independently of others must 
be represented by a discrete material vehicle. 1 
This principle has been largely supported by recent 
investigations. Morphological elements are coming to 
Fig. 147. Rubus fmticosus lacmiatus. The deep dissection 
of the margin of the leaf, which is the character of this 
variety, is seen to be expressed both in the foliage leaves 
and in the petals. Both phenomena are obviously the 
expressions of the same material vehicle of the internal 
character. 
be recognized more and more as combinations of units, 
whilst independence in variation is regarded as the real 
sign of the existence of separate elementary units. 
1 DARWIN, Variations, 2d ed., 1875, II, p. 378. Intracellular Pan- 
genesis (Engl. ed.), p. 19 ff. 
