PROTECTION OF BUDS IN THE TROPICS. 349 
remains until nearly full-grown, its vertical position affording it 
sufficient protection. But as the pinne of the leaf become 
stronger, they expand gradually and open out ; for a considerable 
time, however, the rhachis remains vertical, but as time goes on 
it gradually bends over and assumes first a horizontal position, 
aud then sinks until it hangs downward against the sides of the 
tree. When in the horizontal position I have often seen the 
pinnæ very much scorched and destroyed by the sun. 
The Monocotyledons afford very many instances of this kind of 
protection, among which we may mention the Aroideæ, Musa, 
Canna, Palme, Agave, &c.; among the Dicotyledons, too, we 
find many similar instances. Treub* has already drawn atten- 
tion to the protection gained to species of Brownea and Jonesia, 
and to Amherstia nobilis, Wall., by their young leaves hanging 
down when young; and to these we may add Durio zibethinus, 
Linn., and Galactodendron utile, Humb. & Bonpl. 
3. Protection from Older Leaves. 
When any leaf has become strong enough to resist both the 
sun’s heat and the deleterious atmospheric conditions, it is not 
surprising to find that it should be made useful in protecting 
younger leaves; and so I have been able to find instances where 
the older leaves overlap to form a kind of shield to roof over and 
so protect the younger leaves, or are of such a shape and assume 
such positions that they are able to play a very important part in 
protecting younger leaves. 
A very good example illustrating how older leaves can be so 
arranged as to effectually cover over the young leaves and 
growing-point is found in Uvaria purpurea, Blume. A front and 
also a back view of a shoot of this plant is shown in fig. 7, A 
and B (Pl. XLVIII.), where A is the front view and B the back 
view of a similar shoot. The shoots themselves are in this plant 
slightly inclined to the vertical, so that by this means the older 
leavés are protected from the sun's heat. On examining the 
front view (fig. 7, A), we see that the three leaves a, b, c are so 
arranged that they completely cover over the growing-point and 
its younger leaves, so that these latter are completely shielded; 
while the back view (fig. 7, B) shows how the younger internodes, 
with their smaller leaves, are hidden behind the large leaves. 
The young leaves, as they attain to their mature size, assume the 
* Bot. Centralbl. vol. xxxv. p. 239. 
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