276 THE LOBED LEAF STIPULES. [BOOK i. 



developed,, are found. Subjoined is the result obtained on 

 measuring the relative lengths of these organs. 



A leaf of the 1st pair measured 25 millim. 

 2nd 18 



3rd 12 



4th 5 







5th 



6th 



The four first pairs of leaves had already a distinct petiole ; 

 the fifth leaf was a large palmate or reniform scale, with five 

 unequal lobes. After this a rim is found clasping the nucleus 

 of the axis, the apex of which rises up like a small tumour. 

 As soon as the rudimentary leaf is like a hand with five fingers, 

 little tumours appear at the segments and are afterwards 

 developed into small lobes. The development of the leaves of 

 the Vine and of the Bibes takes place in the same way. 



The toothings of the edge are not visible at the first 

 appearance of the leaf. 



"Formation of Stipules. When the rudimentary leaf of 

 Liriodendron tulipifera is like a small cone, there is no trace 

 of any lateral inequality. The base of the cone is afterwards 

 seen to extend obliquely on each side on the axis of the bud; 

 these extensions finish by forming two projecting tumours, 

 which cover the top of the axis in such a way that their 

 edges touch one another on the side opposite the apex of the 

 leaf. These two tumours are nothing but the stipules. If 

 the entire organ is now isolated, an incompletely closed spur 

 is obtained, the top of which corresponds with the apex and 

 lamina of the leaf, while the edges represent the stipules ; 

 on unrolling this leaf and its stipules a lyre is obtained ; the 

 petiole being still imperceptible. The length of this rudi- 

 mentary leaf is about 1^ millimetre. 



In Tilia europsea, the nascent leaf is originally applied to 

 the axis, then it forms an ovo'id tumour which corresponds 

 with the lamina. The edges of the latter grow obliquely 

 upwards on the nucleus of the axis ; they thus form two 

 projecting points which grow rapidly, and eventually become 



