Here's a smattering of daylilies, for your enjoyment:
Hemerocallis literally means "beauty of the day" in Greek. Calli- means beauty (Callicarpa, as another example, is named for its attractive magenta fruit: calli- = attractive; -carpa= fruit or body, related to corpus). Hemero means day.
The reason for the nomenclature (both scientific and common) is obvious enough to those who know this plant. Each morning, daylilies unfurl tubular flowers that last only until nightfall. The next day, a different bud will open. And so on. The plants typically have enough stems that you get a good bloom mileage, even though no individual flower lasts more than a day.
Before I understood how they worked - quite a while ago - I remember feeling foolish for cutting a stem and adding it to a vase. Daylilies are, obviously, not great cut flowers. This doesn't stop people from collecting them, though -- there are thousands of cultivars ranging in all colors, save for blue and pure white. Personally, I prefer the pale, creamy yellows; 'Lemon Mint' is gorgeous. Of course, the traditional canary hues are classics, too. Daylilies are not native, but are naturalized down in Viginia -- you see them on the sides of roads.
To me, there's a certain romance to the ephemeral quality (there's that Greek again: ephemeral) of the flowers.