Proteoid Roots
Plant species which develop proteoid roots usually lack mycorrhizae,
and unlike mycorrhizal or nodulated roots there is no microbial or fungal associate.
However, there is evidence that their formation may be microbially triggered.
Proteoid root development is greatest in the upper soil horizons, particularly on infertile soils where they can form a thick mat at the interface between the litter and mineral soil horizons.
Inflorescences and foliage of Banksia marginata, a common shrub species in heathlands, woodlands and forests of southeastern Australia.