Species of Medicago are commonly known as medicks. The genus is well-known for containing the agriculturally-important alfalfa (Medicago sativa). It contains over eighty other species, of which some are used for forage, medicine, or agricultural cover crops. Most species of Medicago are low creeping herbaceous plants, but Medicago arborea, or tree medick, is an exception. It is a large shrub that can reach a height of up to 4 meters. Tree medick has silvery-grey leaves composed of three leaflets that are often folded along their midrib. The inflorescences are terminal racemes bearing 4-8 orange-yellow flowers with butterfly-shaped corollas, with the flowers being the largest within the genus.
As Monceau has discovered, the seed pods of Medicago arborea are worthy of close examination. These fruits are flat and spiral-shaped, with the spiral having from .5 to 1.5 rotations or coils. Each legume contains 2-3 seeds. The most beautiful image that I have seen of a Medicago arborea legume is this hand-coloured micrograph made by the artist and professor Rob Kesseler. As explained in the Big Data exhibition catalogue (page 04), Kesseler uses a scanning electron microscope to capture a seed in exquisite detail, then applies colour to introduce “an artistic sensibility intended to create a sense of awe, with the dual purpose of extending knowledge within the respective fields of art and science”.