12 FUTUKK ])UTAN1ST. 



this season I can only shew you Miniiilus and this Fuchsia. 

 The effect is to produce a mosaic which nearly tills the space 

 exposed. One must, liowevei', i-emember that it is the plane at 

 right ang'les to the sun's rays that must be studied. Thus, to see 

 the mosaic of leaf -work on a vertical wall, you must look down- 

 wards, standing about as far from the wall as your own height. 



The second point, the protection of leaves from injury by too 

 strong sunlight, is not so easily seen in this country, but it can be 

 traced, for instance, in the position of the black poplar leaves, which 

 are hung with their flat surface vertical so that they are edgewise 

 to the sun. The same arrang-ment may be seen in the blue gums 

 and other Australian trees, which, in consequence, give but little 

 shade. I thiuk the position of the young leaf surface in all our 

 British plants is worth investigation. 



I have already alluded to the necessit}' of rain-water being 

 rapidly and quickly conducted off the leaves as explaining the 

 smooth, glossy surface of Rhododendron and laurel foliage. If 

 you compare these and other evergreens with an ordinary deciduous 

 leaf, such as that of the chestnut, for example, the difference is 

 most remarkable. The latter has roughnesses, hollows, grooves, 

 and scattered hairs, all of which might afford a lodgment for 

 fungus, spores, and bacteria. This is the beg'inning of the sub- 

 ject, however, for if you watch rain-water falling on any plant, 

 you will find that in some cases it is conducted carefully from leaf 

 to leaf till it reaches the outside circumference of the shadow. In 

 such a case (as in the foxglove ur chestnut) the roots spread out 

 horizontally, so as to be directly under the drip. In other forms 

 the rain-water is conducted down the leaf-stalk to the stem, and 

 trickles down until it reaches the root, which in these species is 

 usually long, or rather deep and vertical (Chickweed, Woundwort). 

 Sometimes the stem is grooved, or the leaves have stipules or 

 auricles, which assist in directing this stream in a definite direction. 

 A good example is the so-called ligule of grasses, which prevents 

 rain with germs and spores from entering the sheath in which the 

 tender, growing part of the stem is enclosed. Nothing is known of 

 the arrangements of most of our British wild flowers. Sir 

 John Lubbock has shown that stipules are used to protect the 

 bud either of the leaf or the growing point of the stem. The 

 common rock-rose protects its bud by them, but those sjDScies of 

 rock-rose which are without these organs protect the bud 1 >y hairs 



