FOLIAGE. I 3 5 



be. The leaflets here also nearly touch one another 

 along their base. 



Rhododendrons sometimes show at the end of their 

 branches a circle of leaves which very nearly touch ; but 

 in this case the number is variable, often 8 or i6. On 

 the other hand, many plants have their leaves arranged 

 in pairs opposite one another, and the pairs cross at 

 right angles, so that here the light is divided amongst 

 four leaves. The Nettle, and almost any plant belong- 

 ing to the great natural order Labiatae, show this 

 clearly. The leaves are broadest at the base, that is 

 the part nearest the stem. The very small young 

 leaves cover any space that would remain above the 

 stalks, and a clump of nettles will show the student 

 very clearly how these " ovate " leaves prevent any stray 

 beam of light from getting through. In fact, scarcely 

 anything is able to grow below a well-developed clump 

 of nettles. Lord Avebury in his book. Flowers^ Fruits^ 

 and Leaves^ which should be a classic for every naturalist, 

 gives an excellent figure of a spray of Horse-chestnut 

 showing how the shape of the leaves, the length of the 

 stalk, and the angle of the leaves to it, all contribute to 

 make the shade which this tree throws as nearly perfect 

 as possible. The leaves, however, are in this case 

 " digitated A young sunflower, before the flower is 

 developed, also shows how the heart-shaped and pointed 

 or " cordate " leaves may be combined to form a beauti- 

 ful dome of foliage of a very effective nature. 



In all these cases, however, the light is supposed to 

 fall upon the top of an upright stem, and the leaves all 

 round the stem share this light among them. 



Three of our common trees, the Beech, the Elm, and 

 the Lime, have a different arrangement. Here the 

 branches are more or less horizontal or drooping and 



