60 BUDS AND STIPULES 



ments of the leaf-blades ; and four smaller, at the four 

 corners, which represent the rudiments of the four 

 leaf-like stipules, two belonging to each leaf. 



Fig. 101 represents a rather more advanced stage, 

 in which two other knobs (one of which is already 

 indicated at the top of the left-hand figure) have 

 made their appearance, which complete the ring of 



til 



If 



Fig. 100. Fig. 101. 



Leaf Development in Galium Mollugo. Highly magnified. 



eight so-called leaves. This figure is taken from a 

 lower node, the leaves of which will be at right angles 

 to those of the previous node. Hence the leaf-rudi- 

 ments which were to the right and left in the first 

 figure now stand above and below, while the last added 

 rudiments stand right and left. The four true stipule- 

 rudiments still occupy the corners. 



Some leaves have what is known as an ' ocrea.' 

 This is a sheath which, taking its origin at the base of 

 the leaf, surrounds the stem above it for a greater or 

 less distance. Ocreas occur in the Plane, Dock 

 (Rumex), Polygonum, Pondweed (Potamogeton), &c. 



