Flower:

Branching clusters at the top of the plant, each branch with numerous whorls of 10 to 20 slender-stalked flowers, usually crowded towards the branch tips and more widely separated below. Flowers are up to about 1/3 inch long (5 to 8 mm) and about as wide, light green to pinkish, 3-sided with 2 series of tepals (petals and similar sepals) and the outer tepals much smaller than the inner.

The 3 inner tepals, also called valves, are round to kidney-shaped, rounded at the tip, distinctly veined across the surface, the edges mostly flat and slightly jagged. At the base of at least one inner tepal is a projection called a grain, about ¼ as long as the tepal, narrowly egg-shaped with a rounded tip, typically 1 grain per flower but sometimes 3 with 2 grains smaller or with only somewhat swollen midveins. Tepals are spreading at flowering time, revealing stamens and styles, and close up after pollination. Flower stalks are very slender and smooth, up to twice as long as the inner tepals at flowering time, with a distinct, usually swollen joint in the lower third, sometimes almost at the base.

Leaves and stems:

Leaves are both basal and alternate, hairless though sometimes rough along the veins on the underside, the edges toothless to shallowly scalloped and flat to weakly crinkly-wavy, pointed at the tip, and the base mostly wedge-shaped to straight across. Basal leaves are lance-elliptic, 6 to 12 inches long and 2 to 4 inches wide, on a stalk shorter than the blade.

Leaves become smaller, more lance-oblong and shorter stalked as they ascend the stem. At the base of the leaf stalk is a brownish papery sheath (ocrea) that surrounds the stem and mostly disintegrates with maturity. Stems are stout, erect, branched from about the middle, ribbed and hairless.

Fruit:

A flower produces a single seed, wrapped in the persistent tepals, which form a capsule-like structure and dry to brown or rusty brown.

Seeds are 3-sided, egg-shaped with a pointed tip, brown to reddish brown, and 3 to 3.5 mm long.

Notes:

Patience Dock is an uncommon weed of roadsides, farm fields, and waste areas but is likely under-reported in Minnesota. There are at least 11 similar Rumex species in the state, 5 of which are native. Some of the distinguishing characteristics are whether the leaves are crinkly-wavy or relatively flat, the shape of the inner tepals at maturity, size and shape of the grains, whether the grains on all 3 inner tepals are about the same size, sometimes the length of the flower stalk, or where the stalk is jointed, or the vein pattern on the leaves. Patience Dock has weakly crinkly-wavy leaves, tepals up to 8 mm long that are kidney-shaped to nearly round and slightly ragged around the edge, usually a single grain about a quarter as long as the tepal, and the flower stalk has a swollen joint near the base. It has the largest tepals of the Minnesota Rumex species, and the (usually) single, small grain makes it unique.

Of the other docks with crinkled-wavy leaves, the most common by far is Curly Dock (Rumex crispus), which has narrower and more egg-shaped tepals, and at least one tepal has a grain nearly half as long as the tepal. Narrowleaf Dock (Rumex stenophyllus) has distinctly toothed inner tepals, each with a grain. Field Dock (Rumex pseudonatronatus) has tepals about half the size and essentially no grains at all. Great Water Dock (Rumex britannica), a native wetland species, has larger basal leaves that are more or less flat, and 3 grains that are all about the same size and shape. Dooryard Dock (Rumex longifolius) has more heart-shaped tepals and essentially no grains. Bitter Dock (Rumex obtusifolius) has broad, heart-shaped basal leaves and tepals with a few large teeth around the edge.

We suspect some of these non-native species are under-reported in the state, largely ignored because they're all assumed to be Curly Dock.