A MANUAL OF BOTANY 33 



from end to end of the leaf, giving off small branches, the 

 leaf is jjinnately veined and the main vein is the midrib. 

 If, on the contrary, a number of equal or nearly equal veins 

 radiate from the base to the margin, the leaf is jMhnately 

 veined. What condition is found in the geranium ? Exam- 

 ine the margin of the leaf. Is it even, not having any 

 irregularities (entire) or is it more or less irregularly lobed 

 and toothed or notched? If tlie notching is shallow, the 

 leaf is toothed; if deej), it is lobed; if the division almost 

 reaches the veins, the leaf is cleft. 



Examine the surface of the leaf, above and below, and 

 observe the color. What difference do you find, and how 

 do you explain it? Observe the presence or absence of 

 leaf hairs on the surface. Examine the leaf for odor. Ex- 

 amine the hairs, (in) and (Ip), and find that some have 

 knobs at their ends. What connection may these hairs 

 have with the odor? Brush the leaf with the fingers to 

 test any difference in the odor. 



On which side are the veins most prominent? What 

 connection have the veins with the petiole? Compare the 

 veins to blood vessels. Is the comparison justifiable ? Com- 

 pare the veins to floor joists to explain their great promi- 

 nence on the under side. Draw (1) a portion of the shoot 

 bearing a leaf; (2) the under view of the blade; (3) the 

 leaf hairs (m) and (Ip). 



Epidermis. Peel off the thin epidermis from the upper 

 and lower surfaces of the leaf, examine with the Ip or hp, and 

 Hnd the irregular epidermal cells and tlie stoniates or small 

 openings witli their two guard cells. Where are the stomates 

 found? Estimate their number in the field of the micro- 

 scope, and with tliis as a starting point, figure the number 

 of stomates on a leaf. 



What do you infer the stomates and guard cells are for? 

 Why do the epidermal cells have such an outline ? Draw 

 the epidermal cells and stomates. 



