This was originally concentrated on wet acid soils in east-central states (K). It was rare to absent on more fertile calcareous soils of Ky., such as most of the Bluegrass region (Bryant 1978). However, it became widely planted, especially along residential roads, despite frequent chlorosis and mineral imbalance that can be overcome with suitable mycorrhizae (Hauer & Dawson 1996). Q. palustris has now become widely naturalized from these plantings, especially along residential roads. Cultivars (and apparent hybrids in some cases) without the distinctive drooping lower limbs of most wild trees are now often used instead of wild types. Clearly adventive records are excluded here, though a few remain uncertain. In Ky. there appear to be occasional wild hybrids with shumardii, phellos and others. Further north, extensive hybridization has been documented among palustris, shumardii and rubra (Morsink & Pratt 1984, Aldrich et al. 2003), with the locally dominant species tending to introgress into the other gene-pools; nurseries sometimes distribute such plants. Based on leaves alone (without its distinctively small acorns), palustris is sometimes confused with other deeply lobed species, especially shumardii and coccinea. Its leaves tend to be smaller and ovate in overal outline (versus often obovate), usually with 5-7 main lobes (versus 5-9); see FNA 3 for details. The longest lobes are usually more spreading (almost perpendicular versus sometimes ascending), and more narrowly shaped, with one of the 2-3 divisions distinctly elongated (versus somewhat truncate, without a more prominent division). In sun-leaves, sinuses are generally C- or U-shaped (versus almost pinched off to an oval). Leaves of palustris are usually plain green to (especially when chlorotic on richer soils) yellowish and paler below, turning pale brown to "bronze" in fall; wild trees are rarely reddish in Ky. but some cultivars may be so. In contrast, leaves of most similar species tend to be deeper green, becoming darker brown or reddish (maroon or scarlet) during fall. Compared to shumardii, terminal buds of palustris have more clearly distinguishable scales. The scale bodies usually become reddish-brown with contrasting grayish margins (versus more unformly reddish or grayish), and the margins are often fringed with long or short hairs (versus glabrous). Buds also tend to be smaller (ca. 3-5 mm long versus 4-8 mm). One-year old twigs are reddish-brown (versus silvery-gray to light brown).