These soon-to-blossom flower buds belong to a plant of Sanguisorba minor (photographed in mid-May, likely in France).
Typically known by the common names of small burnet or salad burnet, this small herbaceous perennial in the Rosaceae is native to Eurasia and northern Africa. However, it has been introduced elsewhere; for example, it grows sporadically throughout the southern United States. The USDA Plant Guide for Sanguisorba minor (PDF) mentions its usefulness for grazing (both livestock and wildlife), erosion control, and pollinators (bees). One of the main uses of this versatile species is in rehabilitating habitats and green strips after disturbances such as fire, in order to “beautify” the landscape and prevent soil loss.
Small burnets are relatively long-lived. Plants grow to between 25 and 55 cm tall (~10-22 in.), with compound leaves consisting of crenate-toothed leaflets. Accurately illustrated by the photograph, the inflorescences are a dense spike with petal-less flowers, each one having approximately 12 stamens. In terms of animal grazing, it is the leaves that are the most prized. However, the seeds are also enjoyed by various birds. Burnet is the common name for all species of Sanguisorba. The genus only contains 9 or so accepted species (according to The Plant List), all growing in temperate climates throughout the Northern Hemisphere. Sanguisorba translates to “blood absorber”, composed of the Latin words “sanguis” (blood), and “sorbeo” (absorb). This originates from the its styptic properties, i.e., being capable of halting bleeding from wounds. Small burnet as well as other species have a longstanding place in European folk medicine for this reason. The specific epithet, minor (small), and name, small burnet, likely refer to its smaller size in comparison to other burnets.
As suggested by the other common name, “salad burnet”, it is also considered a great addition to salads; it can be eaten raw or cooked. The cucumber taste is sometimes used to flavour drinks (primarily in Europe). The famous Englishman, Francis Bacon, is said to have called it one of his favourite herbs, while Thomas Jefferson planted Sanguisorba minor on many occasions as a crop on his farms.