134 THE OAK 



The seed proper fills up the entire cavity en- 

 closed by the fruit-wall above described. It consists 

 of a relatively very thin testa, or seed-coat, closely 

 enveloping the large, straight embryo (fig. 36, f). At 

 the broad end the funicle can be observed attaching the 

 seed to the base of the acorn ; it is inserted laterally, 

 and traces of the aborted ovules may sometimes be 

 found at the point of insertion. The vessels from the 

 funiculus brancn at the chalaza and ramify in the testa. 



The testa is a shining, pale-brown or yellowish skin, 

 consisting only of a few rows of cuboidal, thin-walled 

 parenchyma cells, the outer rows of which may be the 

 integuments, and the innermost possibly belong to the 

 remains of the nucellus ; or the latter may be repre- 

 sented by the outer portion of the thin membrane which 

 includes all that remains of the embryo-sac. A few 

 feeble vascular bundles run through the testa (fig. 37, G). 



The testa is closely applied to the surface of the 

 two stout cotyledons. These fill up by far the greater 

 part of the space enclosed by the thin testa and pericarp, 

 and their shape is almost described in saying that. 

 Each is a colourless, hard, plano-convex body, face to 

 face with the other by the flab surface (fig. 36) ; a trans- 

 verse section of the acorn shows each cotyledon occupy- 

 ing half the circle. At the more pointed end of the 

 acorn these two cotyledons will be found to be joined 

 to the very small embryo (plumule and radicle) by what 

 will on germination lengthen into very short stalks 

 (petioles), but which are at present mere bridges of 



