Growth patterns and biomass allocation to component plant parts inPlantago majorandP. rugeliiwere compared under greenhouse conditions. Within 3 months of germination individuals ofP. majorwere larger and had devoted more dry weight to seed and production of ramets than those ofP. rugeliiregardless of the number and kind of neighbours. No significant differences in percent resource allocation to roots, caudex, leaves, and spikes were observed between plants ofP. majorsubjected to increased interference, although the actual biomass and number of leaves and spikes were reduced. Mean reproductive (spike) allocation inP. majorwas about 21%. Although the root biomass within a treatment was similar for the two species, the percent allocation to roots inP. rugeliiwas two and one-half times greater. Growth ofP. majorwas depressed more by intraspecific neighbours and ofP. rugeliiby interspecific neighbours. These perennial herbs exhibit disparate allocation patterns as young plants that suggest adaptations to different temporary environments.Plantago major, with its early and sustained diversion of biomass to seed production, is distinctly adapted to exploitation of frequently disturbed sites, whileP. rugelii, because of its more extensive root allocation and delayed seed production, seems better adapted to less frequent disturbance.