Plant Science: Areas of interest

Conservation Science

Regional Floristics

Aster Furcatus (FORKED ASTER)

Aster furcatus (forked aster)

The native perennial forked aster (Aster furcatus), found at fewer than 50 sites in six Midwest states, is classified as threatened in Illinois.

During a routine survey of the Chicago Botanic Garden's Mary Mix McDonald Woods, a population of forked aster was found in 1988. Since that time, researchers at the Garden have devoted time and effort toward a better understanding of the biology of this rare plant.

Aster furcatus, which has summer flowers with white rays and yellow disc florets, grows to a height of 1-1/2 to 3 feet. Forked aster is at high risk primarily due to habitat loss, degradation and fragmentation. Because the plant is self-incompatible, it is not capable of producing seed unless cross-pollinated. This condition limits the plant’s ability to pollinate itself or to reproduce with other plants that are genetically similar. As population sizes decrease due to habitat destruction, successful reproduction for Aster furcatus becomes more difficult.

Aster furcatus occurs in various habitats. In Illinois, it is associated with glacial moraines, sedge meadows or woodland ponds. Many of these sites are moderately to heavily wooded, and flowering is sparse to almost nonexistent.

In a recent study by researchers at the Garden, photographs were taken of the canopy above nine populations, using a special 180-degree hemispherical lens. Each population of Aster furcatus was then mapped, and in cooperation with the Institute for Ecosystem Studies, software was used to analyze the percentage of light reaching these plants. A correlation was found between the number of individuals flowering and an open canopy cover. Understanding the complex biology of native plants such as A. furcatus is critical to saving them from extinction.

There are approximately 200 individuals of Aster furcatus in four locations in McDonald Woods. However, the best place to see this rare species is in the Endangered Species Garden at the south end of the Garden.