work. Ixperience has taught us that these larger r> ots need to he close 

 to the surface, and in fact the increase in thickness a? length leads to the 

 apj earance of the roots above the surface, in this way they receiv - more 

 htat an \ ai: than they cou'd at lower depths The absolute ne essity 

 for such a \ osit on is shown by disease, such as 'foot rot' setting in as 

 soon as they are plan ed too deep : and t e recovery of t e plant as soon 

 as it is transplanted and placed at a higher level. 



The fact of the orange tree having a long t ip ro<>t indicates that the 

 soil must be well drained to the depth to which the tup root descends. 



Stem.— To come to the stem, the common division of a stem into heart- 

 wood, sap-wood and bark, answers fairly well to a true physiological 

 division The heart-wood is practically dead wood and serves the par- 

 pose of support to the plant This explains why trees are sometimes 

 found to be living and producing fruit while their stems are mere 

 shells, the heart-wood having been ea'en away by insects. The sap- 

 wood is the portion through which the water and dissolve ! material 

 passes up into the leaves. Tetween it and the bark is the cambium 

 layer, which is constantly reproducing wood on the inner side,, and bark 

 on the outside. The inner bark is the conducting tissue for food des- 

 cending from the leaves to provide material for growth wherever it is 

 taking place The outer bark of the older portion of the s'em is dead, 

 serving as a non-conducting protective covering to the cells lying just 

 below full of food material. If the outer bark is injured, ants and 

 other insects at once attack the inner layer. If they succeed in destroy- 

 ing it all rourd, the passage for food to the roots and to the reproduc- 

 tive cambium h yer is cut off and death ensues. 



The outer bark may be seriously injured by heaping up soil or weeds 

 round the stem, or by lopp'ng off the lower branches so that the sun 

 burns it, or by allowing it to be covered with moss and other growths. 



Leaves. — The leaves are the special parts of the plant which take in 

 the carbonic acid of the air, and in which the plant food is elaborated 

 under the influence of sunshire. The surface of the leaf is perforated 

 with countless numbers of mixed pores through which the carbonic acid 

 passes, the carbon of which is used to form the great bulk of the plant. 

 The pores lead into air passages, and if these are closed, the plant is 

 deprived of air, and cannot c-rry 0:1 the processes of life. These pores 

 also exist on the green portions of the branches, and in a modified form 

 even on the stems. It will be seen therefore how neeessary it :s to the 

 health of the the plant to keep it free from moss, wild pines, and other 

 growths. 



Flowers and Fruit — Coming to the structure of the flowers, they are 

 so adapted that the agency of insects is necessary for carrying the pollen, 

 and it is well therefore for every grove to have its hive of bees. 



If few flowers are formed, or few fruit produced, while the tree is in 

 vigorous growth, it is because the vigour of the tree is thrown in excess 

 into the vegetative side, that is, into production of new leaves and shoots. 

 To alter this, and throw the balance on the reproductive side, it is ne- 

 cessary to give a check to the vegetative vigour, and this may be done 

 by pruning the roots. 



Seeds and Seedlings. — A correspondent writes as follows : — 



" I have a few large grape fruit and orange trees - self planted, and 



