7 8 
Keeble . — The Hanging Foliage of 
so thoroughly acquired the habit of hanging their foliage to 
avoid rain that they work independently of external condi- 
tions, and yet, at the same time, they have not acquired such 
periodicity as alone renders that habit of constant value. 
When the events which occur during the period in which 
branch and leaf alike hang are examined, some light seems to 
be thrown on the significance of this habit. 
About the time that leaves of Amherstia nobilis and 
Browne a grandiceps begin to take on their green colour, 
a periodic movement occurs in their leaflets. This move- 
ment, feeble at first, acquires a gradually increasing range. In 
these trees it is of such a nature that the leaflets move down- 
wards during the sunny hours of the day, so that their sur- 
faces make smaller angles with the vertical. This movement 
is continued during the night, so that in Amherstia nobilis the 
pairs of leaflets hang almost vertically downward. So general 
is this movement, being by no means confined to the young 
green leaves, that the tree at night has a most curious aspect, 
suggestive of the sleeping position assumed by many leaves. 
In the early morning, near sunrise, the leaflets stand well up 
approximately horizontally. Even in leaflets which show 
their maturity by their glossy, dark green colour, and their 
apparently rigid petioles, this diurnal movement occurs, though 
its range is decreased. 
Practically the same movement occurs in the various species 
of Brownea ; and, as an opportunity of raising seedlings 
of Brownea grandiceps occurred, I was able to investigate 
this movement more fully in these. 
As in the adult, so in a seedling Brownea bearing six or 
eight healthy leaves, the leaf-movement was similar to that 
already described. In early morning the leaves stood out 
more or less horizontally ; but frequently, when the plants 
were growing in a room, the upward movement was continued 
for some hours after sunrise ; in later morning the downward 
movement began and continued into the night, giving place 
before daybreak to an upward movement. Thus in one case 
the angles, which a leaf of a seedling Brownea grandiceps 
