The six tepals (referring to the three sepals and three petals that are similar in appearance) of Orange Day-lily (Hemerocallis fulva) may not look like lettuce, but their flavor is similar, which makes them a perfect bright addition to summer salads. Flower buds and withered flowers can also be incorporated into cooked dishes.
Orange Day-lily doesn't sit well with everyone. If you've never tried H. fulva before, I'd recommend starting with a small sample (of course, this advice could go for any new food). I should also mention that while many varieties of Day-lily can be found growing in gardens throughout New England, I cannot speak to their edibility. Some of them may be edible, but I'll leave it to you to do your research. Green Deane explains more about these cautions in his Daylily Dilemma post.