T heme da australis-Eucalyptus Savannah in Papua — Heyligers 
481 
diameters commonly less than 1 mm were still 
found at a depth of 2 m (bottom of the deepest 
pits). Rootlets of 1 or 2 mm diameter were 
seen branching off from the main roots; they 
have a slightly thickened base. 
The conclusion is reached that the Eucalyptus 
species studied have root systems with major 
roots strongly developed in horizontal direc- 
tions, rather close to the ground level, and 
smaller roots penetrating to depths of 2 m and 
over. 
The Shrubs 
Except for young specimens of the eucalypts, 
Albizia procera was the only shrub encountered 
over the whole length of both transects. It was, 
however, more common on the flatter parts. 
Mostly varying in height between 1.5 and 3.5 
m, some reached a height of 8 m and thus 
penetrated into the tree layer. The shrubs grow 
in clusters and consist mostly of little-branched 
shoots, which were generally shedding leaves 
at the time of the investigation. Examination 
of the surface soil and removal of the superfi- 
cial soil layers revealed that the shoots are 
linked by a network of creeping woody root- 
stocks, often as thick as the base of the shoots 
(Fig. 5). From the rootstock branch off vertical 
and oblique roots, which branching does not 
seem to have any correlation with the places 
Fig. 3. The overlapping distribution area on transect 1 of Eucalyptus conjertiflora (with flaky bark) and 
E. papuana (tree with light trunk and slender foliage at right). The tree at the left (with damaged bark) 
is E. alba. In the foreground several branches of Albizia procera shrubs; in the background an area of 
eucalypt regrowth. The ground cover is formed by the T hemeda-Capillipedium group. 
