| English Name | Scientific Name | Spanish Name |
| Tamarind | Tamarindus indica | Tamarindo, Palxuchuc |
| Tarragon | Artemisia dracunculus | Estragón |
| Tea Plant, Black Tea, Green Tea | Camellia [Thea] sinensis | Té negro, Té verde |
| Tea Tree, Cajuput, Punk Tree | — Melaleuca spp M. alternifolia |
— Cayeput Tea Tree |
| Arbol de té | — M. leucadendron M. viridiflora |
— Cayeput (Cajuput) Niauli (Niaouli) |
| Teasel | Dipsacus fullonum | Cardencha |
| Texas Olive, Anacahuita, Little Trumpet | Cordia boissieri | Anacahuite, Camichín, Trompillo, Zalate |
| Thistle | — Cirsium spp C. anartiolepis C. ehrenbergii C. subcoriaceum |
— Cardo Santo, Chicalote, Sueldo Cardo santo, Chin Cardo, C. santo, C. colorado, Mala mujer Cardo santo, Espinilla, Flor de la cruz |
| Thongweed | Himanthalia elongata | Alga espagueti de mar |
| Three-seeded Mercury | — Acalypha alopecuroides A. phleoides |
— El gatito, Rabo de gato Hierba del cancer, H. del pastor |
| Thryallis, Gold Shower | — Galphimia glauca Galphimia humboltiana |
— Tempazcolole Palo muerto |
| Thuja | Thujopsis spp | Thuja |
| Thyme | — Thymus serpyllum T. vulgaris |
— Hierba luna, Serpol, Serpillo, Serpilo, Serpollo Tomillo, Tomello Orégano, O. de frances, O. de la tierra, Oreganón |
| Tiger Flower, Shellflower | Tigridia pavonia | Cacomite, Flor de tigre, F. un día |
| Tilia | Ternstroemia pringlei | Cucharillo, Jaboncillo, Tila, Tilia grande, Trompillo |
| Toadflax | — Linaria cymbalaria L. vulgaris |
— Cimbalaria Linaria |
| Tobacco | Nicotiana tabacum | Tabaco, T. de montaña |
| Tolu Balsam | — Myroxylon spp M. balsamiferum |
— Bálsamo Bálsamo del perú |
| Tomato, Mexican Ground Cherry, Husk Tomato, Winter Cherry | — Lycopersicum esculentum P. pringlei |
—
Tomate Tomate, Tomatillo |
| Toothpick Weed | Ammi visnaga | Ameo, Ami, Biznaga, Dauco, Escarbadientes, Fistra, Gingidio, Perla, Viznaga |
| Touch-me-not, Pale Forget-me-not, Jewelweed, Celandine | Impatiens pallida | Celidonia, Hirundinaria |
| Trailing Indigo | — Dalea reclinata D. versicolor |
— Cola de ratón, Ratoncito Hierba del zorrillo |
| Tree Daisy, Zoapatle | — Montanoa frutescens M. tomentosa |
— Margalogua, Tzoapatle Ciguapatle, Cihuapatli, Gordolobo de terreno, Hierba del to, Zihuapatle, Zoapatle, Zompantle |
| Tree Marigold | — Tithonia diversifolia T. tubaeformis |
— Arnica, Tacote Amarillo Acahual, Acaute, Huevo de Tejón, Tacote |
| Tree-of-Heaven | Ailanthus altissima | Ailanto, Arbol del cielo |
| Truffles | Tuber brumale | Trufa |
| Trumpet Tree | Cecropia obtusifolia | Chancarro, Guarumbo, Guarumo, Hormiguillo, Trompeto |
| Tufted Catchfly | Silene saxifraga | Hierba de las piedras |
| Turks Cap | Malvaviscus arboreus | Bisil, Chilillo, Manzanita, Monacillo, Tulipancillo |
| Turmeric | — Curcuma longa C. zedoaria |
— Azafrán de la India, Batallita, Carmotillo, Curcuma, Dragón, Jengibrillo, Raíz americana, Turmero, Yuquilla Zedoaria |
