Specifically, I'd like to introduce the species Paris quadrifolia, which I met in flowers for the first time two weeks ago, during my annual field course in the volcanic mountains of Auvergne. Apparently, the species has a very broad distribution in Europe (see this map), but in my experience is more commonly found in the understory of mountaineous forests on calcareous soil. It was particularly abundant in the beech (Fagus sylvatica) forests around Lac Pavin, where we spent the week.
The species is very distinctive for having only four broad, verticillate leaves. This explains the second part of the species name (quadrifolia). The first part (Paris), which has nothing to do with the city, may also refer to the pairs of leaves (according to this source), or to the Greek mythological character of the same name.
According to descriptions such as this one, Paris is in fact a variable genus when it comes to floral merism, ranging from 3 to 8. Paris used to be a member of Liliaceae, but now belongs to the small family Melanthiaceae. However, unlike most former members of the Liliaceae who have now moved to various families in the order Asparagales, Melanthiaceae remain in the order Liliales. In total, Melanthiaceae have 17 genera and about 170 species. These include Veratrum and Trillium, which is quite famous in North American temperate forests and looks like the more exuberant, but totally trimerous (both leaves and flowers) version of Paris quadrifolia!