In Ky. this eastern species is generally restricted to mesic forested sites, especially ravines with base-rich soils. It is rare to absent in w. Ky. and w. Tenn., but its range does extend as far as s. Ark. and s. Miss. (K). C. alternifolia is sharply distinct from other North American species of Cornus in its relatively mesic habitat, clustered alternate leaves, and lower chromosome number (2n = 20 versus 22). The East Asian sister species, Cornus controversa Hemsley, is often cultivated, as is alternifolia. These species can be difficult to distinguish with leaves alone (Flora of China 14; F, Y). Flowers of controversa are larger in sepals (ca. 0.5 mm versus 0.1-0.2 mm), petals (3-4.5 mm versus 2.5-3 mm) and other dimensions; fruits are also larger (6-7 mm versus 4-5 mm). It becomes a much larger tree (up to 13-20 m versus 6-9 m); leaf blades tend to be larger (5-13 x 3-9 cm versus 5-10 x 3-6 cm) with more veins (6-9 on each side versus 4-6); fresh twigs tend to be purplish (versus greenish-yellow). A variegated cultivar is commonly sold. Both species have distinctively layered crowns, and are sometimes known as "pagoda dogwoods" or even "wedding cake trees". Although leaves of alternifolia are alternate, they share a distinctive character with all other species of Cornus: when carefully broken in two and the parts slowly separated, silky threads extend to connect the broken veins. This kind of breakage is unknown in other woody plants of Ky., except perhaps to a much lesser degree in some caprifoliaceous species (Lonicera, Viburnum). Curiously, there is virtually no obvious reference to this character in the literature, even on the internet in general (search in 2018 revealed only http:// www.landscapejuice.com/ 2007/09/how-to-identify.html). Otherwise, leaves of Cornus sensu lato can be difficult to distinguish from some species of Lonicera or Viburnum. Leaves of Cornus are consistently entire (versus usually toothed in Viburnum); buds usually have just two scales (versus 2 or several); twigs are often bright reddish or purplish (versus just greenisb to brown). Inflorescences are also similar in their umbellate tendency with small whitish flowers, but flowers of Cornus are 4-merous and non-tubular (versus usually 5-merous and always tubular); fruits are red, white or blue with 1 or 2 seeds (versus red or blue-black with 1 or several seeds).