Discussion
The aim of this study was to determine the drought tolerance of a diverse array of Hakea species to test prediction based on climate-origin and life-history. Sampling 16 Hakea species representing a wide range of climatic niche and life history traits from common conditions estimated genetically determined trait variation. Our results revealed that there was significant variation in the drought tolerance of congeneric species and that biome/climate (rainfall and aridity) of origin was the key predictor of hydraulic traits (stem P50). Other traits contributed to drought tolerance; terete leaf form and higher sapwood area to leaf area ratio (HV) would be expected to reduce whole plant exposure and stress during periods of high evaporative demand. The study is timely given the recent devastating drought episodes experienced across the Australian continent, and in many regions throughout the world.