Aster macrophyllus of Michigan Flora.

In forests of all kinds: beech-maple, hemlock-northern hardwoods, drier sites (with oak, hickory, aspen, jack pine, or mixed conifer-hardwoods), less often in swamps and river banks; common on forested dunes, also in northern rocky forests with spruce and fir. Often abundant after disturbance such as road construction, logging, or fire; spreading to roadsides, railroad embankments, pine plantations.

Eurybia macrophylla is widespread and very variable in size, pubescence, and glandularity. Very rarely a specimen is only sparsely glandular, but even in these individuals, glands can be found along the midveins of the inflorescence bracts. These sparsely gladualr individuals can be distinguished easily from E. furcata by the strongly cordate bases of the lower (or even middle) leaf blades, and the middle and upper leaves much reduced in size. In E. furcata, the base is at most truncate and the leaves are well developed at the upper and middle nodes. Such sparsely gladular individuals of E. macrophylla are more difficut to distinguish from E. schreberi. In E. schreberi glands appear to be most consistently absent from the undersides of the inflorescence bracts and the rays are apparently consistently white. White-rayed plants of E. macropyhylla do rarely occur, but The rays are usually pinkish to blue, though fading to near white with age.

Vegetative shoots with large heart-shaped leaves are generally abundant in forests, and noticeable because of their large size. In comparison, flowering stems are rather sparse in most years, and favor borders, trails, and openings.