hare's-foot bristle fern: a variety of bristle fern
bristle fern: any fern of the genus Trichomanes having large pinnatifid often translucent fronds; most are epiphytic on tree branches and twigs or terrestrial on mossy banks
prevalence: (epidemiology) the ratio (for a given time period) of the number of occurrences of a disease or event to the number of units at risk in the population