368 



13. 



The pollen-grains of V. tricolor are 4-edged, but further- 

 more the same plant can have a few 3- and 5-edged. The 

 grains of V. arvensis are 5-edged, but the same plant can 

 besides have some 4- or 6-edged or both. Finally, types are 

 found that have just as many 4-edged as 5-edged 

 pollen-grains. I suppose these to be of hybrid origin. 

 The leaf-size: 



This character varies in a high degree, but as it is highly 

 dependent on external conditions, the variations are not 



Fig. 3. 

 o: Epidermis-cells from petals (""/i) 

 b: Pollen-grain seen from the edge. 

 c, d, e, f: Pollen-grains seen from above. 

 a-f: i^Vi. 



easy to determine. The sizes must at least be stated in pro- 

 portion to some other organ on the plant, for instance the 

 length of the leaves in proportion to the length of the pe- 

 duncles. Commonly the length of the full grown peduncles 

 is about twice that of the leaves. 



However I have found another type of leaves in the dune 

 populations. They are very short and narrow (fig. 1 c). 

 These leaves have always been somewhat fleshy, 

 to o. The surface of a leaf of this type is only about ^/a— V4 

 of that of a corresponding leaf of a common type. Fig. 4 b 

 and c are leaves of parvifoliate resp. grandifoliate types at 

 the same stage and grown under the same conditions. 



I found leaves of an extremely large size in an arvensis- 

 population upon Tunø (an island in Kattegat) fig. le. The 

 leaves were just as long as the peduncles. Hybrids often 

 have very large leaves. 



