Epiphyllous roots in Begonia and Bryophyllum are

The correct option/answer is Roots arising from leaves.

Let us break down the botanical term step-by-step to understand why this is correct:
1. Etymology of "Epiphyllous":
The term is derived from two Greek words: "epi" meaning upon or on top of, and "phyllon" meaning leaf. Therefore, "epiphyllous" literally translates to something that is situated or growing on a leaf.
2. What are Epiphyllous Roots?
Normally, roots develop from the radicle of an embryo (tap roots) or from stem tissue (adventitious roots). However, in certain plants, specialized roots develop directly from the leaf tissues. These are termed epiphyllous roots.
3. Occurrence in Begonia and Bryophyllum:
In plants like Bryophyllum and Begonia, vegetative propagation occurs through leaves. When leaf margins or injured portions of these leaves come in contact with moist soil, adventitious buds develop at these regions. These buds give rise to roots directly from the leaf laminas or margins. Since these roots arise directly from the leaf, they are classified as epiphyllous roots.

Hence, epiphyllous roots in Begonia and Bryophyllum are indeed roots arising from leaves.