Noun | 1. | ![]() fern - any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores Botrychium, genus Botrychium - grape fern; moonwort Botrychium matricariifolium, daisyleaf grape fern, daisy-leaved grape fern - of North America and Eurasia Botrychium multifidum, leathery grape fern - European fern with leathery and sparsely hairy fronds Botrychium virginianum, rattlesnake fern - American fern whose clustered sporangia resemble a snake's rattle |