Complex sentence: Many of them have massive, fleshy rootstocks, and the largest known fronds of any fern are found in this group in the genus "Angiopteris", native to Australasia and Oceania.
Split into simpler sentences: Many of them have massive, fleshy rootstocks, and the largest known fronds of any fern. These are found in this group in the genus "Angiopteris", native to Australasia and Oceania.