196 THE PATH OF DEGENERATIVE EVOLUTION 



duced, the sole function of which is to protect 

 the axillary bud (fig. 6*7, B, 1, 2). We have now 

 to show that this series is by no means a retracing 



of ancestral stages. 

 All, or nearly all, 

 the Papilionace- 

 ous plants have 

 stipulate leaves ; 

 this shows that 

 the exstipulate 

 leaves of L. tenui- 

 folius do not re- 

 present an ances- 

 tral stage. More- 

 over, before the 

 acquisition of 

 tendrils, vetches 

 had a terminal 

 leaflet (see Vicia 

 Pyrenaica, fig. 

 44) ; none of the 

 reduced leaves in 

 L. tenuifolius re- 

 produce this 



moreover 



FIG. 68. Seedling Vicia of monanthos. 



the simple leaves without leaflets do not represent 

 an ancestral condition ; the winged petiole is not an 

 ancestral character. 



The primary leaves of another vetch Vicia 

 monanthos confirm our conclusion. In this case 



