Carrot family (Apiaceae)
Description: This native perennial plant is up to 2½' tall, forming occasional side-stems. The stems are hairless and rather shiny. The shiny compound leaves are trifoliate. The lower compound leaves have long petioles, which become shorter as the leaves alternate upward along the stems. The leaflets are up to 3" long and 2" across and have finely serrated margins. The terminal leaflet is largest. They are generally lanceolate or ovate in overall shape, although the larger leaflets usually have 1 or 2 sharp lobes (cleft). Slightly rounded compound umbels of yellow flowers occur at the ends of the upper stems. Each compound umbel is about 3" across, and consists of about 12 umbellets. There are about 21 flowers in each umbellet, with the central flower sessile. Each flower is about 1/8" across, and has 5 incurved petals and 5 stamens. Only some of the stamens are clearly visible, however. The blooming period occurs from late spring to early summer, and lasts about 1 month. There is no floral scent. The seeds are oblong and flattened, but not winged, with several lighter-colored longitudinal ridges. The root system consists of a dense cluster of coarse fibrous roots.
Cultivation: The preference is full to partial sun, although light shade under trees is tolerated. The soil should be moist and loamy, and can contain some rocky material. Foliar disease rarely occurs. This plant is easy to grow and maintain.
Range & Habitat: Golden Alexanders is widely distributed, but uncommon or absent in some western and southern counties of Illinois. Elsewhere, it is occasional to locally common. Habitats include moist black soil prairies, openings in moist to mesic woodlands, savannas, thickets, limestone glades and bluffs, powerline clearings in woodland areas, and abandoned fields.
Faunal Associations: The flowers are attractive to many kinds of insects seeking pollen or nectar, especially short-tongued bees, wasps, flies, and beetles. Among the short-tongued bees are such visitors as Green Metallic bees, Masked bees, and Andrenid bees. Wasp visitors include Eumenine wasps, Spider wasps, Ichneumonid wasps, and Crabronine wasps. Bumblebees, Nomadine Cuckoo bees, small butterflies, and plant bugs also visit the flowers. Notwithstanding all of these visitors, this plant is capable of self-pollination. The caterpillars of the butterfly Papilio polyxenes asterius (Black Swallowtail) eat the leaves and flowers.
Comments: Golden Alexanders should not be confused with Pastinaca sativa (Wild Parsnip), which is a weedy Eurasian biennial. The latter is taller, blooms later, and has more leaflets in each compound leaf. It can be particularly difficult to distinguish Golden Alexanders from Thaspium trifoliatum var. aureum (Yellow Meadow Parsnip), which is another native perennial plant. In the latter plant, the central flower of each umbellet has a short petiole, and the achenes are winged, otherwise the two species share nearly the same characteristics. Golden Alexanders is an excellent addition to a wildflower garden because it provides accessible nectar to many beneficial insects with short mouthparts.