Tiller development as a possible factor in the survival of the two grasses, Aristida armata and Thyridolepis mitchelliana.

Abstract

Early tiller development of both Aristida armata and Thyridolepis mitchelliana, determined by microscopic dissection, was comparatively rapid, possib1y reflecting adaptation to an unpredictable environment. Little difference was found between the species in the timing of transition from vegetative to reproductive development at the growing point or in exertion of the inflorescence, although there were marked differences in the rate of elevation of the growing point. The Aristida growing point spent a greater period of time close to the tiller base where it would be relatively inaccessible to grazing. Such behaviour may help explain why Aristida armata appears to displace Thyridolepis mitchelliana in overgrazed pastures.