? 



Ij^^ SCHOOL BOTANY 



Stomata Easily Seen. — The stomata or breathing pores 

 of plants vary greatly in size, but it is seldom that they be- 

 come large enough to be visible to the unaided eye. To be 

 sure, the tiny specks seen in the bark of most young twigs are 

 essentially like stomata in function and similar to them in 

 origin though they are unlike enough in structure to be given 

 a different name and are known as lenticels. The true stomata 

 are very much smaller and most plant students are likely to 

 consider them strictly microscopical in size. However, on 

 the underside of the leaf of the madonna lily ( Lilhtm candi- 

 diim) a common white lily of the gardens, the stomata are 

 visible without a lens. Many other plants have stomata vis- 

 ible with a simple lens and among these may be mentioned 

 several of the monocots such as narcissus, canna, iris, and 

 yucca. The dicots in general seem to have much smaller and 

 more numerous stomata. Some single leaves may have 

 several million stomata on the under surface. 



Leaf Skeletons. — Another method of making leaf skele- 

 tons having some advantages over those given in the last 

 number of this magazine is found in Payne's "Manual of Ex- 

 perimental Botany" recently issued by the American Book 

 Company. In this it is advised to select leaves with a rather 

 firm frame-work. These are to be boiled for fifteen minutes 

 in water to which a heaping tablespoonful of any cleaning 

 powder is added. After boiling place in a dish of clear water 

 to remove the cleaning powder. The leaves may then be placed 

 one at a time on a dinner plate and water allowed to drip on 

 them. This spreads them out on the plate and washes the 



120 



