Small, carrot-shaped roots produced by Cyathochaete avenacea (Cyperaceae) were investigated. Quantitative data are given on their comparative morphology, anatomy and soil-plant relationships. While factors controlling their formation appear to have much in common with those controlling proteoid root formation, their origin and structure are quite different. The cyperaceous roots become endomycorrhizal late in their development. These root structures are essentially distinct from any described in other families, and the term ‘dauciform’ is proposed to distinguish them.