. Heath. — Water-Assoeiations. 153 
Gravel-plains’ heath (North-eastern and Eastern districts). 
A low rainfall, combined with a substratum consisting chiefly of rounded 
stones, favours Zepiospermum-heath. There is a variable amount of surface- 
soil consisting of a loamy sandy clay mixed with 20 to 50 P.c. of stones. 
Although apparently flat, the surface will’ consist of hollows and ridges. Both 
L. scoparium and L. ericoides will be present. Where the shrubs are close, 
there will be a good deal of a species of Hypnum on the ground, and to this 
in part the humus-content of the soil is due. The spinous Discaria toumatou 
and the yellow-leaved Cassinia fulvida may be common. In open spaces, in 
the most stony areas, there will be abundant silvery mats of Raoulia lutescens 
and probably some R. tenuicaulis, while cushions of Scleranthus bi florus will 
be also present. Carmichaelia Sanlalı may be common. 
Stewart Island heath. 
Much of the Zepfospermum-association is situated on ancient dunes and 
has alreadiy been dealt with in the coastal section. Near Port Pegasus there 
is a good deal of close-growing Leptospermum, but it is treated along with 
the allied association of the mountains. 
c. Fern-heath. 
3 F ern-heath i is a most common formation. The dominant | species is Prerid- 
_ formation I do not know. Repeated burning of shrub-heath, of forest and 
even of steppe, in some cases, will establish fern-heath. Eve in the wet 
 elimate of the North-western district Preridium may be seen mr its ap- 
. Pearance as soon as the forest is burnt. 
= In New Zealand, except in specially exposed oil the fern is ever-. 
‚green, consequently RR is no spring ground-vegetation, as in Europe. In- 
deed, the close growth of the leaves inhibits all undergrowth except in open W 
places. Luxuriant fern-heath is frequentiy more than ı1.5mhigh. Suchwilbe 
quite u the floor will be bare, but there will be en. 
