Journal of the Royal Society of Western Australia, 87:49-62, 2004 
Flora and vegetation of the Eastern Goldfields Ranges: 
Part 7. Middle and South Ironcap, 
Digger Rock and Hatter Hill 
N Gibson 
Science Division, Department of Conservation and Land Management, Wildlife Research Centre, 
PO Box 51 Wanneroo WA 6065 
El neilg@calm.wa.gov.au 
(Manuscript received July 2003; accepted June 2004) 
Abstract 
A study of the flora and plant communities of part of Forrestania greenstone belt between 
Middle Ironcap and Hatter Hill (some 80 km ESE of Hyden), recorded a total flora of 345 taxa of 
which 342 were native and three were introduced. Three species of threatened flora and 29 taxa 
being considered for listing were found. Ten species are considered to be endemic to the range and 
a further eight species are restricted to similar landforms within 100 km of the range. A new 
species of Stenanthemum is only known from two populations. Despite considerable mining and 
exploration activity in the area, the flora and vegetation remain poorly known. Thirty-eight 
quadrats were established along the range system and data from these quadrats were used to 
define four community types. Differences in these community types were strongly related to 
edaphic gradients. Very little of the Forrestania vegetation system is reserved and the results of 
this survey support recommendations for the establishment of nature reserves to conserve this 
vegetation system. 
Keywords: flora, vegetation. Goldfields, Ironcap, Hatter Hill, Digger Rock, Western Australia, 
greenstone 
Introduction 
The Forrestania greenstone belt extends from Mt 
Holland south to Hatter Hill, a distance of some 70 km, 
and lies 80 km east of Hyden. This narrow greenstone 
belt is composed of an undulating plain of mafic and 
ultramafic lithologies and abrupt ridges of banded 
ironstones, and forms part of the western most 
greenstone series (Chin et a\. 1984). These belts are 
common landforms of the Eastern Goldfields and have 
been heavily exploited for mineral exploration and 
mining for over 100 years. Despite this, a detailed 
knowledge of the flora and vegetation of individual 
ranges is still lacking although broad scale structural 
vegetation mapping (Beard 1972) and regional surveys 
are available (Newbey & Hnatiuk (1988). 
The aim of this series of papers is to report on detailed 
floristic studies on some of these ranges to address this 
deficiency (Gibson et al 1997; Gibson & Lyons 1998a,b; 
Gibson & Lyons 2001a,b). This work has highlighted the 
high biodiversity values of these ranges as centres of 
endemism and restricted vegetation assemblages within 
the subdued landscapes of the eastern goldfields. 
Study Locality 
The study area lies ca 80 km ESE of Hyden and covers 
the section of the Forrestania greenstone belt between 
Middle Ironcap and Hatter Hill (Fig 1). The northern 
portion of this belt was burnt by a large, extremely hot. 
© Royal Society of Western Australia 2004 
wildfire in summer of 1993 that consumed almost all 
vegetation between Mt Holland and Middle Ironcap. The 
northern section of the belt runs roughly north-south 
then swings north west-south east near South Ironcap. 
The regional geology of the study area has been mapped 
and described in the Hyden 1: 250000 sheet (Chin et al. 
1984) and the geology and landforms have also been 
summarized by Newbey (1988). The study area has been 
tectonically stable since the Proterozoic (600-2500 My go). 
The major landscape features are controlled by the 
Archaean (2500-3700 My old) granites that underlie most 
of the study area, and have weathered into gently 
undulating plains and broad valleys covered by Tertiary 
soils (< 65 My old). The narrow Forrestania greenstone 
(Archaean mafic and ultramafic lithologies) belt has 
several banded ironstone units (formed from lacustrine 
deposits of iron oxides and quartz sand) up to 30 m thick 
which form the abrupt ridges of North, Middle and 
South Ironcap. Some areas of Tertiary laterite were also 
found associated with the greenstone belt (Chin et al 
1984). Gold was first discovered in the Forrestania area 
in 1915 and there has been a long history of mineral 
exploration and mining along this belt. There are 
presently three large mines operating in the area; at 
Forrestania, Middle Ironcap, and Digger Rocks. 
The climate of the region is warm dry mediterranean 
with warm winters and hot summers. Mean annual 
rainfall at Hyden is 336 mm, with moderate seasonal 
variation. The driest year on record was 1972 with 159 
mm, and the wettest was 1942 with 572 mm. Most rain 
falls in winter, generally associated with frontal activity 
from May through August. Summer rainfall (to 50 mm) 
is highly erratic and results from thunderstorms. The 
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