Leaves of many species are characteristically lobed while some have toothed leaves, except for the shingle and willow oaks, whose leaves are entire rather than lobed or toothed.
Oaks are common in woodlands throughout Ohio.
Large quantities of young leaves and sprouts are toxic when consumed in spring as are green acorns in the fall. Poisoning occurs when over half the diet is oak buds and young leaves, or acorns, for a period of time. Livestock have also been poisoned by drinking water in which oak leaves have soaked. Plant tannins or their metabolites cause gastrointestinal and renal dysfunction. Symptoms appear several days after the period of consumption and include abdominal pains, weakness, anorexia, colic, constipation, depression, diarrhea, presence of blood in urine, and jaundice.