After the group's last visit to Fosse Meadows, I was checking the characters of some waterside sedges and noticed a glaring discrepancy in the literature. The ligule shape is a distinctive feature in some species, for example, it is obtuse in Carex riparia (Greater Pond-sedge), but acute in Carex acutiformis (Lesser Pond-sedge). Both of these species have 3 stigmas and produce 3-sided nuts, so the ligule character aids identification. Another, more infrequently found species, is Carex acuta (Slender Tufted-sedge) which has 2 stigmas, and produces 2-sided, biconvex nuts, and so, can be easily separated from the previous two species. But, if you haven't got stigmas and ripe nuts, you are forced to rely on vegetative characters. The BSBI handbook Sedges of the British Isles and The Vegetative Key to the British Flora agree that the ligule of C. riparia is obtuse, and that the ligule of C. acutiformis is acute, but they differ about C. acuta. The Sedge Book says its ligule is obtuse, whereas The Vegetative Key says it is acute. The 'Book of Stace' doesn't use ligule characters, so is no help. What to do? Who is right? How does this happen? Perhaps someone out there on the Plant ID course or the Botany for Beginners course can help.