Flower:

Loose branching cluster of 3 to 13 flowers at the top of the stem, the branches widely divergent with a single flower at the tip of a sparsely hairy stalk.

Flowers are about ¼ inch diameter with 5 oblong-elliptic yellow petals 1 to 2 mm long. In the center is a green ovary covered in numerous pale green styles (the structure called a hypanthium), surrounded by many yellow stamens. The 5 sepals around the base of the flower are triangular, about as long as or somewhat longer than the petals, and strongly bent back.

Leaves and stems:

Leaves are basal and alternate along the stem. Basal leaves are variable in shape, some undivided with a single large, egg-shaped to nearly round blade, others more oblong in outline, compound or lobed with 3 to 11 leaflets/divisions, some intermediate between the two, the largest leaves up to 10 inches (27 cm) long including the stalk. Edges are toothed, surfaces are sparsely to moderately hairy.

Stem leaves become smaller and shorter stalked as they ascend the stem, but are more uniform in shape, 1 to 2¾ inches (1 to 7 cm) long, typically with 3 leaflets, the terminal leaflet largest. At the base of the stalk is a leaf-like appendage (stipule) up to 1 inch (8 to 25 mm) long, coarsely toothed or lobed along the edges. Stems are erect to ascending, multiple from the base, variously covered in long, spreading hairs, usually more sparse on the upper stem.

Fruit:

As fruit develops, the hypanthium rises above the sepals on a stalk (stipe) that elongates up to 7 mm (~¼ inch). Fruit is a dry seed maturing from green to reddish-brown, the body flattened oval, 2 to 3 mm long with a hooked beak at the tip that is nearly as long as the body. 

Notes:

Spring Avens is a fairly recent discovery in Minnesota, which is a bit north of its documented native range, but it seems reasonable it is naturally migrating northward due to climate change. The (currently) lone herbarium record is from Carlton College's Cowling Arboretum, where it was first discovered along a trail in 2021. The DNR has found it a few times in our southeast counties, along trail edges (which could be introduced by human activity) but also in more natural settings, which could be native populations. They've deemed it native to Minnesota until facts prove otherwise. 

When flowering or fruiting it is fairly easy to recognize by the tiny yellow flowers and head of lamb chop shaped seeds elevated above the sepals. Prior to flowering, the leaves can resemble other related Avens species, but are generally smaller and frequently more variable in shape; look for long, spreading hairs to help distinguish it from the others.

The flowers may also resemble those of some Ranunculus species, but Spring Avens seed heads are easily distinguished by the stipe and long beak on the seeds. Of note is there are a number of Minnesota observations on iNaturalist claiming to be Spring Avens, but I would not confirm any of them when the only evidence is a single photo of some early leaves.