Untitled - The Alfred Russel Wallace Website

390 NOTES OF A BOTANIST CHAP.
panduriform outline. Sometimes there is a pair of
sacs, one on each side of the midrib, but in most
cases the two sacs are confluent into one, which has
a medial furrow along the upper side.
I proceed to describe a few forms of sacs in
various species of Tococa. In one species (T. diso-
lenia, MSS. hb. 1412) which grows by forest-streams
entering the lower part of the Rio Negro, the
leaves of each pair are very unequal, and the larger
of the two is
(11 by 3^- inches) alone
The axils of the inner pair of ribs are
sacciferous.
perforated,
entrance to two tubes or fistulse one on
giving
each side of the midrib which conduct to a large
basal sac, inhabited by small brownish ants, which
pour out of the tubes and patter over the leaves to
attack any animal that disturbs their domicile.
In most species, however, the sac springs at once
from the base of the inner ribs, through whose perforated
axils the ants have access to it without any
intervening tubular way.
T.
bullifcra, Mart., grows in moist forests about
the mouth of the Rio Negro, and is of humbler
growth than the other species of the genus, reaching
barely 5 feet ; but the berries are more juicy
and better flavoured than in any other Tococa,
although so scanty and perishable that they cannot
possibly serve as food for ants except for a very
short period, and can hardly have influenced them
in the choice of an abode. The leaves are long-
lanceolate, either subequal and then with a large
fusiform sac at the base of each of the pair, or very
unequal and then the smaller leaf esaccate. The
sacs afford
refuge to multitudes of minute reddish
ants which are fragrant when crushed. Most species