Potentilla erecta (less commonly P. tormentilla)
This rather dainty and ubiquitous flower is tormentil. You’ll find it creeping all over the moor, from the tops of tors and open moor to riversides and woodland. It looks like a tiny buttercup, but look more closely: it’s actually a member of the rose Rosaceae family, and one of only two roses that has four petals instead of five (the other being burnets). It flowers on Dartmoor from late May through to September, and in the autumn when the heather is past its best it really comes to the fore. At this time of year, it is also an increasingly important food source for solitary bees.
Tormentil is said to get its name from the Latin tormentus. Its red rhizomal roots have been used as a folk medicine since at least Roman times, and it is supposed to be a cure for diarrhoea, sore gums and ulcers among other ailments. Hence the name – it will ease your torment. The roots also contain a lot of tannin and are astringent, and have apparently been used as flavourings for liquors and tonics, while the red pigment has been extracted for paints and dyes.
I love to see this little flower out on the moor. It’s a nice, easy to spot plant with an interesting folk history. Keep an eye out for it next time you’re out on a walk.