The effect of water stress on the life cycles of Erodium crinitum Carolin and Erodium cicutarium (L) L'Herit ex Aiton (Geraniaceae)

Erodium cicutarium (L.) L'Herit. ex Aiton (Geraniaceae) from temperate Mediterranean Eurasia is naturalized across large areas of arid and semi-arid Australia to which Erodium crinitum Carolin is native. The response of seed cohorts from Koonamore, SA, of these two species to water stress on plant height, leaf numbers, buds and fruit under artificial drought was investigated to see if there were significant differences in their life history strategies which might reflect their evolution under different water regimes. Although in E. cicutarium plant size, leaf and bud numbers and fruit/plant biomass ratio were significantly lower under drought, flower and fruit number, fruit size and total mass were unaffected. In contrast, E. crinitum was largely unaffected by the drought conditions, showing only an increase in the fruit/plant biomass ratio.