NEW ZEALAND—EGBERT H. WALKER 321 
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variation. They are of two kinds: first, the original tussock grass- 
lands of native species (pl. 9, fig. 2), and second, the pastures with a 
sward formed of introduced species (pl. 9, fig. 1). The history of 
New Zealand is largely the story of man’s replacement of the native 
bush with pastures and the exploitation of the native grasslands in 
feeding his flocks of sheep. In the ashes of the bush he planted grasses 
and began the process of adapting the sward-forming techniques, so 
well developed in his native England, to the conditions of this new and 
promising land. He fought a continual battle with the few native 
plants with weedlike tendencies and the more numerous and generally 
more vigorous exotics, which he intentionally or unintentionally 
brought from the far parts of the earth. From early blunderings he 
has now developed the technique of sward growing to a very advanced 
degree, and agricultural progress or deterioration in large parts of 
North Island and certain regions of South Island depends on the com- 
position and condition of this pasture sward. Much land formerly 
covered with fern, scrub, or blackberry is now grass-covered, with a 
high sheep-carrying capacity. It was a most enlightening experience 
to see the work of the Animal Research Station at Ruakura near 
Hamilton in Auckland Province, in breeding and mixing strains of 
grasses, on which, with proper rotation, an amazing number of sheep 
can graze throughout the year without additional feed. The various 
types of these artificial grasslands of North Island have been carefully 
mapped and analyzed in a publication by Madden (19). Something 
of the history and significance of these grasslands can be gleaned from 
the account written by an English‘agronomist, Stapledon, who visited 
Australia and New Zealand in 1926 (25). The planted pastures of 
South Island, developed by essentially the same means, are well 
described in Hilgendorf’s ecological survey of the grasslands (13), 
which supplements Madden’s. 
The natural grasslands are very different from the man-made 
pastures. They occur most extensively in South Island, but smaller 
areas are to be found in North Island, especially in the central plateau. 
A relatively low rainfall with a cooler and more even temperature are 
among the principal factors governing the development of grasslands 
rather than shrublands or “bush.’”’ The plant composition of this 
formation varies considerably according to local conditions. Pas- 
toralists generally recognize five tussock grasses. ‘Two of them, snow 
grass (Danthonia raoulii var. flavescens) ? and red tussock (D. raoulu 
var. rubra) are the tall tussocks, 3 to 6 feet high, while the short 
tussocks, 1 to 2 feet high, are the silver tussock (Poa caespitosa) and 
the hard or fescue tussock (Festuca novae-zealandiae). The blue 
tussock (Poa colensoi) is only 6 to 9 inches high. 
2 The names, both common and scientific, in general use in discussing these grasses vary considerably. 
This makes research on the grasslands rather difficult. Zotov (28) recognizes only four tussock grasses. 
