I was looking at the Great Plant Picks list of recommended grasses, and I wonder why they exclude Carex, which I find is such a useful plant in the garden.
Great Plant Picks does in fact list two different Carex species but they are not on the list of grasses because Carex is a type of sedge, and sedges are not grasses. An article entitled “Sedges Have Edges” from Hilton Pond Center for Piedmont Natural History has a detailed explanation of the differences among grasses, sedges, and rushes. All three are graminoids, but grasses are in the Family Poaceae, sedges are Cyperaceae, and rushes are Juncaceae. According to the article, “a simple ‘touch test’ is the giveaway for sedges, whose stems when rotated have a very noticeable triangular shape–hence a total of three ‘edges.’ ”