68 



up the albiiminous food materials, and the 

 function of the sieve-tubes is to conduct them. 



Within the Phloem is the XyJem (Wood), which 

 shows two Frotoxylem groups. The Metaxylem 

 meets in the middle. The protoxylem consists 

 entirely of Sjnral Tracheides ; the metaxylem con- 

 sists of Parenchyma and Scalariform Tracheides. 

 The function of the Parenchyma is to store up 

 Carlohydrates (Starch), and the function of the 

 Tracheides is to carry water. 



2. The Leaves. 



As seen in section, beginning at the upper surface, 

 present the following structure : — 



(a) Epideemis. This consists of small cells, packed 

 so that there are no spaces. The outer walls 

 are cuticularised. 



(b) Palisade Paeek'CHYMa, consisting of long 

 narrow cells rich in chlorophyll grains. 



(c) SpojfGY Paeenchyma, consisting of rounded or 

 irregularly-shaped cells. These cells are separ- 

 ated by large spaces. 



(d) LowEE Epideemis, which is interrupted by 

 stomata. The stomata are confined to the middle 

 part of the under surface. 



Each vein is a vascular bundle, surrounded by 

 colorless parenchyma. The bundle has a well- 

 defined endodermis, and exhibits the same 

 structure as the stem bimdles. 



