Maximilian's Sunflower is named after an early botantical explorer of North America. This plant has attractive foliage and flowers, and it is easy to identify because of the unusual leaves. These narrow leaves are longer (up to 12") than the leaves of other Helianthus spp. in Illinois, and they have a distinctive light green or greyish green appearance because of their fine white hairs. Two native species, Helianthus grosseserratus (Sawtooth Sunflower) and Helianthus giganteus (Giant Sunflower), also have narrow leaves, but they are not covered with dense white hairs. Another species resembling Maximilian's Sunflower is Helianthus salicifolius (Willow Sunflower), which occurs in the southern Great Plains. The Willow Sunflower has narrow leaves that are even longer than Maximilian's Sunflower, but they are only ½" across or less. The Willow sunflower is not known to occur in Illinois at the present time, although a colony of 500 plants once existed in Cook County before it was destroyed by commercial development. These plants were undoubtedly adventive from the west.