THE CARPEL AND OVULES 205 



The sections may be stained with a solution of methyl-green in 

 1 per cent, acetic acid : this will give good results, but all the 

 contents of the embryo-sac can be readily seen in good sections 

 without any staining at all. 



Examine first with a low power, and observe 



1. The carpel, having a structure not unlike that 

 of an ordinary leaf, and consisting of an upper and 

 lower epidermis with some four layers of mesophyll 

 between them. Note the suture or junction of the 

 two margins of the carpel, which thus incloses a central 

 cavity. 



2. The ovules (macrosporangia) seated in this 

 cavity, and attached near the margins of the carpel : it 

 has already been noted that there are two rather irre- 

 gular rows of ovules in each carpel, therefore at most 

 only two ovules appear in each section. 



The form of the ovule is anatropous : it consists of 

 the following parts : 



a. The funiculus, or stalk, which adheres through 

 the greater part of its course (as the raphe) to the 

 body of the inverted ovule. A procambium bundle, 

 connected with a bundle at the margin of the carpel, 

 traverses it longitudinally. 



The body of the inverted ovule consists of 



I. Two integuments, each several layers of cells in 

 thickness, the outer being united with the funiculus : 

 the integuments cover the body of the ovule completely, 

 excepting a narrow channel (micropyle) near its apex. 

 Within the integuments lies 



c. The nucellus, an oval mass of cellular tissue in 

 which is embedded 



d. The embryo-sac (macrospore), a large oval cell.. 



