14- THE OAK. 



egg-shaped body consists chiefly of two longitudinal 

 halves, separated by a median plane which runs through 

 the acorn from top to bottom. These two halves, lying 

 face to face so closely that it requires the above manipu- 

 lation to enable us to detect the plane of separation 

 (Fig. 2, Z), are not completely independent, however; at 

 a point near the narrower end each of them is attached 

 to the side of a small peg-shaped body, with a conical 

 pointed end turned towards the narrow end of the 

 acorn. This tiny peg-shaped structure is so small that 

 it may be overlooked unless some little care is exercised, 

 but if the hard masses are completely torn apart it will 

 be carried away with one of them. 



The two large plano-convex structures are called the 

 cotyledons, or seed-leaves (Fig. 2, c), and they, together 

 with the small peg-shaped body, constitute the embryo 

 of the oak. The peg-shaped body presents two ends 

 which project slightly between the two cotyledons be- 

 yond the points of attachment to them ; the larger of 

 these ends has the shape of a conical bullet, and is di- 

 rected so that its tip lies in the point of the narrower 

 part of the acorn ; the other, and much smaller end, is 

 turned towards the broader extremity of the acorn. The 

 larger, bullet-shaped portion is termed the radicle (Fig. 

 2, r), and will become the primary root of the oak- 

 plant ; the smaller, opposite end is the embryo bud, and 

 is termed the plumule (Fig. 2, pi], and it is destined to 

 develop into the stem and leaves of the oak. If the ob- 

 server takes the trouble to carefully separate the two 



