Ewart . — The Effects of Tropical Insolation. 471 
Brownea capitellata , LJ, B T 5 3. Midrib pale green, leaf inrolled 
longitudinally, chlorophyll-grains quite small and pale yellowish 
colour, no assimilation perceptible. L^, B^. Leaf just unrolled, 
pale brownish green along veins, here in parts faint assimilation, in 
rest of leaf none and only faint greenish colouration. L 4 f, B 
Expanded and nearly fully green, assimilation moderately to quite 
active. 
Amherstia nobilis, Wall, L T 5 T , B T s -g . Chlorophyll-grains small 
and pale yellowish green. No assimilation perceptible. L -J, B -f* 
Assimilation weak to imperceptible. L -|-§, B T 9 -g-. Chlorophyll-grains 
fairly large, still somewhat yellowish green, assimilation weak. L §§, 
B Still quite red but reddish colour disappearing at apex, and 
leaflets commencing to rise and expand. Chlorophyll-grains fairly 
large and yellowish to nearly normal green, assimilation weak to 
moderately active. Leaflet on cut branch in water exposed for five 
hours to full sunlight slightly fading in colour, assimilation imper- 
ceptible, being next day weak to moderately active. L B 4. Adult 
fully green leaf, assimilation active. Leaflets on cut branches insolated 
for five hours show fairly active assimilation, but after a whole day’s 
insolation, assimilation is fairly active, to weak or in some cases imper- 
ceptible, next morning being fairly active. 
In Amherstia it is only when the red colour disappears and 
the leaf is expanded and green that assimilation becomes 
fully active. In the hanging position the assimilatory power 
of the leaflets being feeble or absent, the loss to the plant, 
by the non-exposure of the leaflets to light, of material which 
might possibly have been assimilated, is but trifling; whilst 
the gain, in the protection afforded against excessive transpi- 
ration or exposure to strong illumination and in the rapidity 
with which the young leaflets are thereby enabled to develop, 
is very great. If branches of Amherstia are bent so that the 
red hanging foliage-leaves are exposed to as much sunlight 
as possible, and the leaflets are supported on wires and 
spread out in a horizontal position, they may wilt or fade 
at the edges or tip or over irregular areas in the lamina, 
the growth of the leaflets is retarded and at the same 
time the exposure to excessive illumination causes a distinct 
