THE 
HEW PHVTOliOGIST. 
Vol. 4 . No. 4 . April 29 TH, 1905 . 
ON THE SIGNIFICANCE OF SPINES IN DISCARIA 
TOUMATOU, RAOUL. (RHAMNACEAE). 
By L. Cockayne, Ph.D. 
(With Plate II.). 
D ISCARIA TO U MA TO U, the ‘Wild Irishman’of the Colonists, 
is a common New Zealand xerophytic shrub, or occasionally 
a small tree, chiefly remarkable for being abundantly furnished with 
rather long and very pungent spines, which are in fact shoots of limited 
growth capable of assimilating carbon dioxide. The characteristic 
stations of this plant are :—stable sand-dunes ; stony plains, river¬ 
beds and terraces; dry, frequently clayey hill-sides, and slopes of 
stony debris, or even rock-faces. In some places, the plants are 
isolated ; in others, they form dense thickets, unpleasant to pene¬ 
trate. The species under consideration, although closely allied to 
the Australian Discaria australis, Hook . 1 is endemic in the New 
Zealand biological region, being found in both the South and North 
Islands, but not extending northwards in the latter beyond about 
37 ° north lat. A few plants are to he met with in Chatham Island, 
but it has not been recorded from the other outlying islands or 
from Stewart Island. 
In stature, Discaria Toumatou varies much according to climate, 
being occasionally a small tree 2 reaching a maximum height of 6 m. 
or so on river-flats in certain parts of the wet mountainous region 
of the South Island. More commonly it is a shrub, at times low 
growing (see Fig. 2, Plate II.) or even prostrate in the dryer districts 
or in extreme xerophytic stations. The exterior branches are very 
1 By J. D. Hooker in the Flora Novae-Zelandiae the New Zealand 
plant was named D. australis var. apctala. 
2 Kirk states it was formerly used for building purposes where 
large timbers could not be obtained. Forest Flora of New 
Zealand, 1889, p. 283. 
