Vot. XI. No. 266. 



THE AGRICULTURAL NEWS. 



221 



STUDENTS' CORNER. 



JULY. 



Second Period. 



Seasonal Notes. 



Examine several plants, and find out if the way in 

 which the leaves are borne possesses any relation to the parts 

 of the stem; observe also the different kinds of leaves that 

 may be borne by a plant, and the places on the plant where 

 they are found. Why are leaves usually flat and thin t 

 Adduce any reason for their being cylindrical (roughly 

 speaking) and tapering; that is to say of a form in which 

 there is far less surface, in proportion to the bulk, than is 

 usually the ca.se What are the uses of the veins of leaves, 

 and how would you show that they possess these uses? The 

 interior of a leaf generally exhibits large spaces between the 

 cells, and there is very free communication between this part 

 and the outer air: why is this? How is a leaf enabled, to 

 some extent, to regulate the rate at which the water leaves 

 it, that it receives from the roots? In considering the 

 different structures that are usually found in leaves, in 

 relation to their uses, it should be remembered that those 

 of many plants give ofl" water freely and in large quan- 

 tities, in bright sunlight, the purpose being to prevent 

 the temperature of the leaves from rising to such a degree as 

 to cause injury to the protoplasm in them; this fact has been 

 demonstrated particularly for cotton, in Kgypt. State what 

 you know concerning protoplasm, and mention the parts of 

 an ordinary woody plant that consist of cells which contain 

 this body. 



In what way are leaves concerned in the nutrition of 

 the plant which bears them? State how you would show, in 

 a simple manner, that leaves are necessary for the proper 

 nutrition of a plant. The fact that leaves derive from the 

 sun the energy which they require for building up the food 

 bodies that are formed in them lends much importance to 

 the results of shading plants and to the question of the 

 degree of shade that they require at different stages of their 

 growth. It is evident, again, that the amount of develop- 

 ment of the stem and roots of a plant depends to some 

 extent on the effective leaf surface that belongs to it. This 

 is illustrated by the circumstance that trees growing in dense 

 forests possess tall, slender trunks that branch very high up; 

 for the lower branches have been killed through the want of 

 light; and further the resulting reduction in the amount of 

 leaves that they bear generally causes the wood to be of 

 a soft kind, containing relatively little fibrous tissue. The 

 latter condition receives contrast from the case of trees of the 

 same kind growing in the open, where the access of light and 

 the consequent free growth of leaves causes the rate of 

 nutrition to be such that large, strong trunks full of fibrous 

 elements are formed. 



The largest leaves, in plants of the .same kind, are most 

 often to be found on those receiving the best supply of 

 water; in fact, in any given plant, the size of the leaves as 

 compared with those of other plants of the same sort is 

 closely dependent on the ease with which the plant may 

 obtain water. This is why the leaves borne by the suckers 



of plants that sprout out quickly during the rainy season are 

 generally larger than the older, ordinary leaves on the 

 plant — a matter that may often be observed in lime trees, to 

 give an example. With such leaves there is usually the 

 accompaniment of a softer woody tissue. 



In a collection of similar seedlings, or in different 

 varieties of the same plant, those individuals or forms bear- 

 ing the largest leaves may be regarded as the most hardy 

 and as possessing the best root development — the latter 

 property being a consequence of the former. This fact should 

 be remembered when selection is being carried out. 



Questions for Candidates. 

 Preliminary Questions. 



(1) Give a short account of the different kinds of buds. 



(2) What is meant by stomata, and what are their uses 

 to the plant? 



(3) State, giving examples, what you know of the 

 different shapes that are possessed by leaves. 



Intermediate Questions. 



(1) How are the buds of plants employed in their 

 propagation? 



(2) State briefly how the stomata of a plant are enabled 

 to open and close. 



(3) Give examples of plants in which the area of the 

 surface of the leaves has been much reduced, in order to 

 enable the plant to withstand dry conditions. 



Final Questions. 



(1) Supply examples of the kinds of protection for the 

 interior that may be found in leaf buds and in flower buds. 



(2) Write an account, illustrated with e.xamples, of the 

 ways in which leaves are enabled to reduce the amount of 

 transpiration. 



(3) What cases have you observed, of the modificatiop 

 of leaves to fulfil purposes other than those which are usual? 



THE THIRD INTERNATIONAL RUBBER 



EXHIBITION. 



L^seful suggestions, arising as the result of expe- 

 rience in connexion with the forwarding of samples 

 of rubber for exhibition, are contained in the Agri- 

 cultural Bulletin of the Straits and Federated Malay 

 States for March 1912, and are reproduced here : — 



(1) All cases of exhibits should be fastened by screws 

 and not nails. Nailed eases frequently split and are spoiled 

 for returning. 



(2) The name of the estates, settlement or State should 

 be stencilled or printed on two or three faces of the case. 

 Consignee's address should appear on the top of the case. 



(3) Cases to be returned should have the addresses 

 printed on a board and screwed face downward on the top of 

 the case when consigned to New York. 



(4) Full instructions: if for competition, description of 

 contents, number of cases, weight of rubber, whether ofl'ered 

 for sale or to be returned, address of returning, should be 

 communicated to the local secretary or direct 



(5) Instructions should not be enclosed in the cases of 

 rubber. 



(6) Instructions, part to local secretary or direct, and 

 part to agent or friend, should be avoided. 



(7) Cases should be numbered, and the contents des- 

 cribed on the case, as well as mentioned with instructions. 



