METROSIDEROS ROBUSTA, A. Cunningham. 
THE NORTHERN RATA. 
OrpeErR—MYRTACEA. 
(Plate CXX VIII.) 
Tue northern rata is one of the largest trees in the New Zealand flora, being 
commonly from 6oft. to rooft. in height, and from 3ft. to 12ft. in diameter, while 
much larger specimens are occasionally found, the largest recorded being 68it. 
in circumference and upwards of 22ft. in diameter. It is invariably erect, never 
climbing, although bushmen and settlers frequently state that it climbs the 
loftiest trees, and sooner or later squeezes them to death in its iron clasp. In 
proof of this they assert that, when felling huge ratas, they often find a dead tree 
in the centre of the rata: this is a common occurrence, but it by no means 
follows that this species is a climber. The error is simply due to impertect — 
observation, which has led careless observers to confuse the preceding species, 
M. florida, which is a true climber, with M. robusta: at the same time the 
remarkable habit of the latter species often causes the death of trees on which 
it may be growing, although not by climbing. 
This error is not confined to bushmen and settlers, but has been adopted 
by many writers on New Zealand, and widely circulated. I extract the follow- 
ing from Wakefield’s ‘‘ Handbook for New Zealand”: “ Rata (Metrosideros 
robusta). There are several varieties of this tree: one grows at first as a para- 
site, creeping in numerous stem-like ropes up the trunks of the other forest- 
trees, gradually enclosing them till they perish, and then uniting to form a noble 
tree taller than that which it has destroyed, with an enormous trunk, but hollow 
within.” This appears a very circumstantial statement, but it will be shown 
presently that the mode of growth is the reverse of climbing. 
The seeds of this species are very minute and dustlike, and, as they are 
produced in large quantities, it is not surprising that they are often carried by 
the wind into the forks of lofty trees, and readily germinate in the vegetable 
mould formed by the decaying leaves of orchids and other epiphytes which are 
so abundant on the arms of large trees in the northern forests. The seedling 
rata commences life as a born aristocrat ‘‘ high up in the world,” and grows as 
freely in its elevated station as the more humble tawa or rimu below, until the 
limited supply of nutriment at its high level is exhausted, when it boldly 
stretches one or more aérial roots down the trunk of the supporting tree, until 
they reach the earth in quest of an increased food-supply: as increased nourish- 
ment is thus drawn directly from the soil, the aérial roots gradually assume the 
appearance of stems, and present one or two features of great interest. If, 
during the progress of growth, a single root-stem becomes forced away from the 
supporting trunk for a portion of its length, a lateral root is given off at mght 
angles, and grows horizontally around the supporting trunk until it returns to 
the opposite side of the main root-stem: sometimes several lateral arms are 
given off in this way: it is difficult to conceive of any phenomenon connected 
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