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PART II. — VEGETABLE HISTOLOGY. 



cross-sections of it and studying it with care. Does it represent the bi-facial or 

 centric type ? Observe the excessively thick-walled epidermal cells, the well- 

 developed hypoderma, the large intercellular spaces beneath the stomata, the 

 peculiar chlorophyll-bearing parenchyma cells with internally folded walls, the 

 scattered resin-passages, and the pitted parenchyma cells and fibro-vascular 

 bundle, both enclosed within the bundle sheath. Make drawings and careful 

 descriptions of each of the leaves studied. 



8. For the study of sepals and petals with reference to the venation, the 

 presence or absence of stomata, the character and distribution of the coloring 

 matter and the cause of the velvety appearance which some parts possess, the 

 flowers of Tropeolum majus, of Torenia Asiatica and of the common Pansy 

 may be selected. Cross-sections may be made in the same manner as was 

 directed for ordinary leaves. 



