Which of the following genera is associated with coralloid roots?

Step-by-step solution

Roots in Cycas are of two types - normal and coralloid roots. Coralloid roots are irregular, negatively geotropic, dichotomously branched coral like roots which do not possess root hair and root caps. Coralloid roots have a symbiotic association with blue-green algae like Nostoc and Anabaena species.