genus Microsorium ge·nus·mic·rosorium uncommon noun 1. tropical usually epiphytic ferns; Africa to Asia and Polynesia to Australia SynonymsMicrosoriumgenus Microsorium Related words Broader terms fern genus Parts Polypodiaceae Part of climbing bird's nest fern WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.