46 
NATURE NOTES. 
But, perhaps, the most universal adaptation displayed by 
leaves to free themselves from water is the formation of long 
slender apices and pointed teeth along their margins. 
Go among the water-loving willows and sprinkle their leaves 
with water, and observe how quickl}' and readily the drops run 
down and fall off from their tapering extremities. 
A considerable part of Stahl’s work is occupied in a considera- 
tion of these apices, and a few simple experiments mentioned 
there are so instructive, and } et so easily performed, that I would 
advise you to repeat them. He marked half-a-dozen leaves with 
long slender ends ; three of these he left as they were, the apices- 
of the others he cut off and rounded. He then sprinkled all six 
with water, and watched. He found that while the leaves with 
the pointed ends were quite dry in twenty minutes, those which 
he had rounded were still moist, and remained so for upwards 
of an hour. The leaves of our willows and poplars are good 
examples to confirm this. 
I will not mention any other of the numerous means adopted 
by the vast variety of leaves to be found in our English forests 
and hedgerows, but will leave you to observe the rest for your- 
selves, believing that in doing so you will find much pleasure 
and enjoyment. 
Rudolf Beer. 
The relation of the form and position of the leaf to rainfall 
may be easily studied in our common lime, the leaves of which 
it is most interesting to watch during a shower. Owing to their 
sloping position the pointed apex is lower than the stalk, so that 
raindrops falling on the polished surface all run towards the tip, 
wliere they collect in a larger drop which rapidly twists off from 
the point. It is also worth while to notice the shape of the leaf- 
stalk. In many plants its upper surface is grooved, forming 
a channel well fitted to carry off the water which has fallen on 
the blade, but in the lime there is no such channel, the leaf-stalk 
being rounded, and the same will be found to hold in other trees, 
c.g., black poplar, where the leaves slope downwards towards a 
pointed apex. Where the water is run off from the tip it is at 
once got rid of, but if carried off by the petiole gets only as far 
as the twig or branchlet ; in cases such as these, herbaceous 
plants have often developed ingenious ways for getting rain 
drops down to the ground. The lines of hairs running down 
th^ stem of the common chickweed from the base of the leaf- 
stalk to the next lower node form a well-known instance. 
Professor J. Wiesner, an Austrian botanist, has recently been 
studying the behaviour of plants under artificial rain. He finds 
that under continuous rainfall many plants soon shed their leaves 
and decay, while others can stand it for many months. The first 
set he calls ombropJiobe , the second ombrophil. As we should ex- 
pect, plants growing in dry places are generally ombrophobe ; 
l)ut the Professor did not find that plants loving damp situations 
