Flower:

3 to 12 flowers in a compact, flattish cluster at the tip of the stem. Flowers are flattened, about 1/8-inch across, with 4 petal-like sepals that are broadly triangular to egg-shaped to semi-circular, 1 opposite pair often slightly larger than the other. Sepals are green, yellowish green or reddish green. In the center is a translucent nectar disk surrounded by 2 to 8 yellow-tipped stamens. At the base of the cluster are several leafy bracts, green to yellowish-green, egg to fan-shaped.

Leaves and stems:

Leaves are ¼ to ½ inch long and up to ¾ inch wide, shallowly lobed with 5 to 9 notches around the edge, and on stalks up to 1¾ inches long. Basal leaves are round to kidney-shaped, typically with a deep sinus at the base, the 2 basal lobes often touching, and hairless to variously covered in white hairs, though the stalk may have reddish hairs. The 1 to 3 stem leaves are alternate, shorter stalked, hairless or with a few purplish hairs, round to kidney to fan-shaped. Flowering stems are erect, hairless, and may branch in the upper plant. Prostrate stems (stolons) are sparsely covered in white or reddish hairs.

Fruit:

Fruit is a 2-lobed capsule, oblong in outline, containing numerous reddish brown seeds.

Notes:

Nationally, Iowa Golden Saxifrage is only known from a few locations in southeast Minnesota and northeast Iowa, in what's known as the Driftless Area that covers portions of Minnesota, Iowa, Illinois and Wisconsin, though this species is not known to occur in either Illinois or Wisconsin. Primarily a Canadian species, the US populations are considered disjunct, some even consider it a separate species. According to the DNR, in Minnesota its habitat is typically talus slopes that stay cool and moist all summer. It was listed as an Endangered species in 1984 due to its rarity in the state and specialized habitat, which is threatened by logging, grazing and recreation. It is similar to the related American Golden Saxifrage (Chrysosplenium americanum), which is hairless, has mostly opposite, stalkless or short-stalked leaves that do not have the deep sinus at the base, typically has purplish, red or orange stamens on the flowers, and grows more prostrate.

While researching this species, a review of C. americanum images taken at Banning State Park in Pine County revealed something remarkable. We had been scouring ravines in the park searching for Viola selkirkii and came upon what we assumed was C. americanum growing out of moss-covered rock. The flowers had yellow anthers, which is atypical for C. americanum, but we were already aware the population at Falls Creek SNA had yellow anthers so didn't think much of it at the time. And after all, C. iowense was only in Fillmore and Houston counties, right? Upon closer inspection of our images, the leaves in a few of them looked odd, with deep lobes at the base where they are usually nearly straight. Then it hit: this was in fact C. iowense. This would also be the first US population found outside the Driftless Area. We have since learned that taxonomists no longer consider C. iowense to be endemic to the Driftless area and this find further supports that. Cool.