Index of plants by genus
| Species | Common Name | Family |
| Taxodium distichum | Baldcypress | Taxodiaceae |
| Taxus canadensis | Canada Yew | Taxaceae |
| Teucrium canadense | Canada Germander | Lamiaceae |
| Thalictrum dasycarpum | Purple Meadow-rue | Ranunculaceae |
| Thelypteris palustris var. pubescens | Marsh Fern | Thelypteridaceae |
| Thelypteris phegopteris | Long Beech Fern | Thelypteridaceae |
| Thuja occidentalis | Eastern White Cedar | Cupressaceae |
| Tilia americana | American Linden | Tiliaceae |
| Toxicodendron radicans | Eastern Poison Ivy | Anacardiaceae |
| Toxicodendron rydbergii | Western Poison Ivy | Anacardiaceae |
| Toxicodendron vernix | Poison Sumac | Anacardiaceae |
| Tradescantia ohiensis | Ohio Spiderwort | Commelinaceae |
| Triadenum fraseri | Marsh St. John's Wort | Hypericaceae |
| Trillium grandiflorum | Great White Trillium | Liliaceae |
| Trillium recurvatum | Prairie Trillium | Liliaceae |
| Triosteum perfoliatum | Wild Coffee | Caprifoliaceae |
| Tsuga canadensis | Eastern Hemlock | Pinaceae |
| Typha angustifolia | Narrow-leaved Cattail | Typhaceae |
| Typha latifolia | Broad-leaved Cattail | Typhaceae |
© 2004 Michael Hough