MANUKA THICKET. 73 
race which reproduces its like. On the contrary, it presents a 
diversity of forms which are seemingly impossible to classify. Some, 
it is true, are distinct races, but most are probably unfixed hybrids 
between races not yet defined by the plant-classifier. There are also 
occasionally individuals with beautiful double flowers (fig. 43), and 
others with crimson blossoms, of which the form known in gardens 
as Leptospermum Nichollsii (in general incorrectly spelt ‘* Nichollii’’) 
is one of the most handsome shrubs in cultivation. 
Wherever the soil is extremely poor, as on dry gravel plains, or 
particularly “sour,” as that sterile clay, wet in winter and baked 
hard in summer, which forms the Auckland gumlands, a more or 
less dense association of manuka occurs. At the present time it is 
impossible to say what was the primitive physiognomy or composi- 
tion of the latter association, for repeated burning must have greatly 
altered the original arrangement of its members as well as their 
relative abundance. In any case, it seems safe to assume that a 
plant with such habits and potentialities as the manuka would 
formerly, as now, stamp the association with its own remarkable 
individuality. 
The manuka formation, described below under the designation 
“ manuka thicket,” is of varied origin. It may be a natural successor 
to rain-forest, or a stage of succession in the development of river- 
bed, swamp, or bog vegetation, and certainly it can take the place 
of forest which man has destroyed. 
A great many members of the formation are shrubs with small 
leaves of a heath-like character. There are generally a good many 
tuberous orchids to reward careful search if looked for at the season 
when they may be expected to flower; indeed, amongst the manuka 
is the dwelling-place par excellence of these curious plants, so greatly 
esteemed by many, partly for their beauty, partly for the rarity of 
certain species, and partly because they are frequently considered 
to be extremely valuable. 
The number of orchids provided with tuberous roots enabling 
them to grow in the soil, as distinguished from the perching-orchids, 
with their water-absorbing, aerial roots, is 57, belonging to 21 
genera. Compared with their gorgeous tropical relatives grown 
in hothouses, the New Zealand orchids are the most modest of 
country cousins, yet their attractions are not to be denied. Some 
have flowers so constructed that cross-pollination by insects is 
