Flower:

Flat clusters (umbels) 1½ to 3 inches across, made up of 7 to 16 groups (umbellets) of up to 20 flowers each. The tiny individual flowers are bright yellow, 1/8 inch across with 5 petals folded inward and 5 yellow stamens. Flower stalks above the leaves are 2-4 inches long; a plant typically has 2 to several clusters.

Leaves and stems:

Basal and lower stem leaves are heart-shaped, with rounded or blunt tips and long stalks. All leaves have finely toothed edges and are a bit glossy, often with a spot of purple where the leaf or end leaflet meets the stalk.

Higher stem leaves become compound in three leaflets or just deeply three lobed at the base, the leaflets or lobed divisions narrower, lance shaped. Stems and leaves are usually smooth or faintly hairy. Stems are single, or multiples arising from the base.

Fruit:

Fruit is 2-sectioned, oval, slightly flattened, ridged, eventually splitting into 2 seeds.

Notes:

Very similar to Golden Alexanders (Zizia aurea) which is generally more common, Z. aptera can be distiguished by unlobed or simple basal leaves and upper leaves compound or lobed leaves in threes where Z. aurea's basal leaves are compound in threes and upper compound leaves are typically in multiples of three. Also similar is Yellow Pimpernel (Taenidia integerrima), which has rather airier clusters and toothless leaflets.