SOUTHWEST INTERZONE Ladiges et al. 2005

s. The Southwest Interzone has been discussed by Nicholls (1933), Burbidge (1960) and Hopper (1979),
the former two authors named it Hesperonotian and Interzone 1 respectively. Burbidge mapped Interzone 1 in her Fig.
1, and Hopper (1979) refined its boundaries in his Fig. 2, but also referred to the area as the “Transitional Rainfall
zone”. Nicholls based his area on “a less well-defined borderland, overlapping the Eremian [and Southwest Australia]
and agreeing fairly closely with Prescott’s Sclerophyll Woodland and Scrub” (Nicholls 1933: 94), whereas Burbidge
described it as “a triangular area lying between the South-West Province and the Eremaea proper” (Burbidge 1960:
80). Given that these description are vague, we follow the area descriptions and name of Ladiges et al., namely “Semiarid
area inland and adjacent to the South-west region, including open scrub and shrublands (on sand plains, sand over
laterite or loamy soils) in the bioregions of Yalgoo, Avon Wheatbelt and Mallee” and that of the synonymised area