DUNE-HOLLOWS. oD 
In the Auckland Botanical Districts such sand shrubland would 
also contain the tall mingimingi (Leucopogon fasciculatus), growing as 
a prostrate shrub ; the white tea-tree (Leptospermum ericoides), simi- 
larly prostrate, though in a forest it would be a good-sized tree ; 
the heath-like pomaderris (Pomaderris phylicaefolia), and perhaps 
the austral broom (Carmichaelia australis), distinguished by its broad 
flat green stems, absence of leaves, and pods with red seeds. Cassinia 
retorta, mentioned already, is, of course, abundant; but, strange to 
say, it remains erect where most of its fellow-shrubs hug the sand. In 
Southland the manuka association appears absent. In Stewart Island 
the puheretaiko (Senecio rotundifolius) forms dense thickets. 
Hollows in the dune areas are very frequent, the sand bemg 
blown away until the ground-water is almost reached, for wet sand 
is not moved by wind. Where the water cannot get away there 
will be swamps, and even shallow lakes. 
In sand-hollows the pioneer plant is the sand-sedge (Carex pumila), 
which soon builds miniature dunes. The sand-gunnera (Gunnera 
arenaria), forming close mats of small pale-green leaves flattened to 
the ground, is also very abundant in many localities. Such hollows 
finally become occupied by introduced grasses and plants of the 
clover family. These hollows, where circumstances permit, may be 
made truly profitable through growing lucerne (Medicago sativa), 
but the grazing by sheep or cattle would be almost certain in time 
to cause fresh drifting of the sand. Such grazing needs, then, to be 
conducted with extreme caution. Dune-hollows must not be looked 
upon as having any close relationship to sand-grass dune, but they 
may rightly be considered different plant-formations, the beginning 
of a dune-hollow association being due to a topographical change. 
Let us leave the dunes, and, in imagination, sail up one of those 
wide estuaries in the west of the North Auckland Botanical District— 
Hokianga or Kaipara Harbour—or one of the tidal rivers of the east 
—the Whangarei, for instance. If it is high tide, we shall see on 
either side of the stream a belt of close-growing, dull-coloured, small 
trees, rising out of the turbid water. These consist of the mangrove 
(Avicennia officinalis), and the sight is one almost unknown in any 
other land outside the tropics. It is, in fact, one of the natural 
wonders of New Zealand. 
Now, quite undeservedly, the mangrove has got a bad reputa- 
tion. A mangrove swamp is supposed to represent all that is most 
