About Tetrapteron graciliflorum (Hook. & Arn.) W.L.Wagner & Hoch
Tetrapteron graciliflorum, a species of evening primrose, has the common name hill suncup. It is native to Oregon and California, where it grows in several habitat types, most often on clay soils. It is an annual herb that typically has no stem, and instead produces an upright, nodding inflorescence. It has a cluster of narrow leaves, each between one and ten centimeters long. Its flowers have bright yellow petals that measure 0.5 to two centimeters in length. The fruit is a leathery capsule under one centimeter long, with four chambers that hold bumpy brown seeds.
