A rare and endangered new subspecies of Eucalyptus sargentii (Myrtaceae) with high potential for revegetation of saline sites from south-western Australia and notes on E. diminuta and E. sargentii subsp. fallens
Eucalyptus sargentii subsp. onesia Nicolle subsp. nov. is described. It is known from less than ten small populations in the central wheatbelt of southwest Western Australia, with all populations occurring on highly saline sites and possibly endangered by increasing salinisation. E. sargentii subsp. onesia differs from subsp. sargentii primarily in the lignotuberous, mallee habit, making it preferable to subsp. sargentii for salt reclamation projects, due to its propensity to regenerate following fire or cutting. Extensive field examination, seedling trials and observations of cultivated material have indicated that E. sargentii subsp. fallens is not specifically distinct from E. diminuta and I regard the former as synonymous with the latter. E. diminuta is recircumscribed to include populations from Eurardy Station in the north to near Watheroo in the south.