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 (11 by 3^- inches) is alone sacciferous. 

 The axils of the inner pair of ribs are perforated, 

 giving entrance to two tubes or fistulse one on 

 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 per- 

 forated 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, reach- 

 ing 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 



