DEVELOPMENT OF LEAVES ANT) STIPULES 51 



gradually widens into a ridge, the two ends of which 

 eventually meet, forming a ring. 



One part raises itself above the rest and forms the 

 leaf-stalk ; the two side pieces become the stipules. 

 They grow upwards and inwards, finally forming a 

 hood over the growing-point. About the time when 



81 82 



TULIP TUBE (Liriodendron tnlipifcra). 



FlG. 80. Very young leaf and stipule, x 20. FIG. 81.- Do. do. second stage, x 20. 

 'FIG. 82. Do. do. rather more advanced stage, x 20. 



the stipules meet the leaf-blade commences. It is at 

 first a very narrow, delicate, hyaline membrane. The 

 bud then assumes the appearance shown in fig. 80. 



The next stage (fig. 81) shows the growth of the 

 leaf-blade, which is more developed in fig. 82. Fig. 17, 

 p. 14, shows how closely the young leaf fits in the 



E'2 



