button fern: Jamaican fern having round buttonlike bulbils
fern: any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores
omomyid: extinct tiny nocturnal lower primates that fed on fruit and insects; abundant in North America and Europe 30 to 50 million years ago; probably gave rise to the tarsiers; some authorities consider them ancestral to anthropoids but others consider them only cousins