Major items
| Organic | Scientific name | Common name | Part | Origin |
| Tabebuia avellandeae Lorentz ex Griseb (syn Handroanthus impetiginosus (Mart ex DC) Mattos) | Pau d'Arco | |||
| Tabebuia heptaphylla (Vell) Toledo (syn Handroanthus heptaphyllus (Vell) Mattos) | Ipe roxo | bark | S-America | |
| Tabebuia impetiginosa (Mart ex DC) Standl (synPau d' Arco | Pau d'Arco | bark | S-America | |
| Tabebuia ochracea (Cham) Standl (-> Handroanthus ochraceus tree | Golden trumpet (Cham) Mattos subsp Ochraceus) | root | C-America | |
| Tabebuia rosea (Bertol) DC | Pink trumpet | leaf | C-America | |
| Tabebuia serratifolia (Vahl) G Nicholson (= HandroanthusExtract | Tahuari extract | bark | S-America | |
| Tabernaemontana crassa Benth | Adam's Apple Flower | W-Africa | ||
| Tabernanthe iboga Baill | Iboga | bark, root | W-Africa | |
| Tagetes erecta L | Marigold | flower | MidEast | |
| Tagetes filifolia Lag | Irish lace | leaf, flower | C-America | |
| Tagetes lucida Cav | Sweet Scent Marigold | entire plant | Americas | |
| Tamarindus indica L | Tamarind | leaf, fruit, seed | C-America | |
| Tamarindus indica L | Indian Tamarind | W-Africa | ||
| Tanacetum balsamita L | Costmary | herb | W-Europe | |
| Tanacetum balsamita L subsp balsamitoides (Sch Bip) Grierson | ||||
| Tanacetum cinerariifolium (Trevir) SchBip (= Chrysanthemum cinerariifoliumflower | Pyrethrum | flower | MidEast | |
| Tanacetum coccineum (Willd) Grierson | Persian Insect Flower | |||
| bio | Tanacetum parthenium (L) Sch Bip | Feverfew | flower | SE-Europe |
| Tanacetum pseudoachillea C Winkl | herb | Central Asia | ||
| Tanacetum vulgare L | Common tansy | herb | C-Europe | |
| Taraxacum mongolicum Hand -Mazz / Taraxacum sinicum Kitag | China | |||
| bio | Taraxacum officinale F H Wigg aggr | Dandelion | flower | SE-Europe |
| Taxillus chinensis (DC ) Danser | herb | China | ||
| Taxus baccata L | Common Yew | needle | W-Europe | |
| Tecoma stans (L) Juss ex Kunth | Yellow trumpet | leaf, bark | C-America | |
| Telipogon astroglossum | Ecuador | |||
| Telipogon venustus | Ecuador | |||
| Tephrocactus alexanderi | America | |||
| Tephrocactus articulatus | America | |||
| Tephrocactus dactyliferus | America | |||
| Tephrocactus diadematus | America | |||
| Tephrocactus ferocior | America | |||
| Tephrocactus fulvicomus | America | |||
| Tephrocactus geometricus | America | |||
| Tephrocactus hossei | America | |||
| Tephrocactus kuehnrichianus | America | |||
| Tephrocactus ovatus | America | |||
| Tephrocactus platyacanthus | America | |||
| Tephrocactus reicheanus | America | |||
| Tephrocactus sphaericus | America | |||
| Tephrosia hirta Buch-Ham (-> T villosa (L) Pers subsp Villosa) | ||||
| Tephrosia purpurea (L) Pers | Sharpunkha | |||
| Tephrosia villosa (L) Pers subsp Villosa | ||||
| Tephrosia virginiana (L) Pers | Devil Shoestring | N-America | ||
| Tephrosia vogelii Hook f | Fish Poison Bean | leaf | W-Africa | |
| Terminalia arjuna (Roxb ex DC) Wight & Arn | ||||
| Terminalia bellirica (Gaertn) Roxb | Beleric, Bastard Myrobalan | Indian Sub | ||
| Terminalia catappa L | Tropical almond | leaf, fruit | C-America | |
| Terminalia chebula Retz | Black Myrobalan | herb | Indian Sub | |
| Terminalia chebula Retz / Terminalia chebula Retz var tomentella Kurt | China | |||
| Terminalia oblonga (Ruiz & Pav) Steud | Peruvian almond | bark | C-America | |
| Terminalia sericea Burch ex DC | root | E-Africa | ||
| Ternstroemia pringlei (Rose) Standl | Tilia star flower | flower | C-America | |
| Tetracarpidium conophorum (Müll Arg) Hutch& African (-> Plukenetia conophora Müll Arg) | AfricanWalnut | seed | W-Africa | |
| Tetraclinis articulata (Vahl) Mast | Sandarac | herb | N-Africa | |
| Tetragastris panamensis (Engl) Kuntze | Copal, Mountain copal | bark | C-America | |
| Tetrapanax papyrifer (Hook) K Koch | China | |||
| Tetrapleura tetraptera (Schumach) Taub | pod | W-Africa | ||
| Teucrium canadense L | Germander | herb | N-America | |
| Teucrium chamaedrys L | Wall Germander | herb | ||
| bio | Teucrium montanum L | Mountain Germander | herb | SE-Europe |
| Teucrium polium L | Poley | herb | N-Africa | |
| Teucrium scorodonia L | ||||
| Thalictrum foetidum L | Fetid Meadow rue | herb | E-Europe | |
| Thapsia garganica L | ||||
| Thaumatococcus daniellii (Benn) Benth ex B D | Miracle Berries | arillus | Africa | |
| Thaumatococcus daniellii (Benn) Benth ex B D | Miracle Berry | W-Africa | ||
| Thelocactus bicolor | America | |||
| Thelocactus buekii | America | |||
| Thelocactus conothelos | America | |||
| Thelocactus ehrenbergii | America | |||
| Thelocactus garciae(Thelocactus hexaedrophorus) | America | |||
| Thelocactus heterochromus | America | |||
| Thelocactus hexaedrophorus | America | |||
| Thelocactus krainzianus(Thelocactus leucacanthus) | America | |||
| Thelocactus leucacanthus | America | |||
| Thelocactus lloydii | America | |||
| Thelocactus lophothele(Thelocactus rinconensis) | America | |||
| Thelocactus macdowellii (Echinomastus macdowellii) | America | |||
| Thelocactus matudae(Thelocactus tulensis) | America | |||
| Thelocactus nidulans | America | |||
| Thelocactus rinconensis | America | |||
| Thelocactus saussieri | America | |||
| Thelocactus schwarzii | America | |||
| Thelocactus tulensis | America | |||
| Thelocactus wagnerianus(Thelocactus bicolor) | America | |||
| Thelocephala frankhauseri | America | |||
| Thelocephala napina | America | |||
| Theobroma cacao L | Cocoa | seed | Africa | |
| Thevetia neriifolia Juss ex A DC (-> Th peruviana (Pers) K Schum) | ||||
| Thevetia peruviana (Pers) K Schum | Yellow Oleander | |||
| Thlaspi arvense L | Penny Cress | seed | MidEast | |
| Thuja occidentalis L | Thuja | Europe | ||
| Thuja orientalis L (= Platycladus orientalis (L) Franco) | Thuja | needle | E-Asia | |
| Thymus × citriodorus (Pers) Schreb (Th pulegioides × Th vulgaris) | Lemon Thyme | N-America | ||
| bio | Thymus serpyllum L | Wild Thyme | herb | SE-Europe |
| Thymus vulgaris L | Garden Thyme | herb | N-Africa | |
| Ticoglossum oerstedii | Ecuador | |||
| Tieghemella heckelii (A Chev) Roberty | Makore | seed | W-Africa | |
| Tilia cordata Mill | Little Leaf Linden | |||
| bio | Tilia platyphyllus Scop | Big Leaf Linden | flower | SE-Europe |
| Tilia tomentosa Moench | Silver Lime | flower | E-Europe | |
| Tillandsia usneoides (L) L | Spanish moss | aerial part | C-America | |
| Tinospora cordifolia (Willd) Hook f & Thomson | ||||
| Tinospora sinensis (Lour) Merr | SE Asia | |||
| Tinospora tomentosa (Colebr) Hook f & Thomson (syn T sinensis (Lour) Merr) | SE Asia | |||
| Tithonia rotundifolia (Mill) SF Blake | Mexican Sunflower | leaf | C-America | |
| Torreya grandis Fort | China | |||
| Toxicodendron pubescens Mill | Poison Ivy | leaf | W-Europe | |
| Toxicodendron quercifolium (Michx) Greene (-> T pubescens Mill) | Europe | |||
| Toxicodendron vernix (L) Kuntze | ||||
| Trachelospermum jasminoides (Lindl) Lem | China | |||
| Trachylobium verrucosum (Gaertn) Oliv (-> HymenaeaAfrican CopalGaertn) gum | East African Copal | gum | W-Africa | |
| Trachyspermum ammi (L) Sprague ex Turrill | Bishop's Weed | seed | Indian Sub | |
| Trachyspermum copticum (L) Link (-> T ammi (L) Sprague ex Turrill) | ||||
| Trema guineensis (Schumach) Ficalho (-> TremaLarge Poison-peach | Large Poison-peach | W-Africa | ||
| Trema orientalis (L) Blume | Large Poison-peach | W-Africa | ||
| Trianosperma ficifolia Mart | Tayuya | root | S-America | |
| Tribulus terrestris L | Caltrop | China | ||
| Trichilia catigua A Juss | Catuaba | bark | S-America | |
| Trichilia heudelotii Planch ex Oliv | bark | W-Africa | ||
| Trichocentrum albococcineum | Ecuador | |||
| Trichocentrum candidum | Ecuador | |||
| Trichocentrum carthagenense | Ecuador | |||
| Trichocentrum nanum | Ecuador | |||
| Trichocereus atacamensis | America | |||
| Trichocereus boliviensis | America | |||
| Trichocereus bridgesii | America | |||
| Trichocereus candicans(Echinopsis candicans) | America | |||
| Trichocereus chiloensis | America | |||
| Trichocereus huascha | America | |||
| Trichocereus pachanoi | America | |||
| Trichocereus pasacana | America | |||
| Trichocereus peruvianus | America | |||
| Trichocereus Schigra | America | |||
| Trichocereus terscheckii(Echinopsis terscheckii) | America | |||
| Trichoceros antennifer | Ecuador | |||
| Trichoceros muralis | Ecuador | |||
| Trichoglottis pusilla | Ecuador | |||
| Trichopilia eneidae | Ecuador | |||
| Trichopilia fragrans | Ecuador | |||
| Trichopilia hennisiana | Ecuador | |||
| Trichopilia laxa | Ecuador | |||
| Trichopilia marginata | Ecuador | |||
| Trichopilia olmosii | Ecuador | |||
| Trichopilia suavis | Ecuador | |||
| Trichopilia tortilis | Ecuador | |||
| Trichopilia turialbae | Ecuador | |||
| Trichosalpinx arbuscula | Ecuador | |||
| Trichosalpinx berlineri | Ecuador | |||
| Trichosalpinx chaetoglossa | Ecuador | |||
| Trichosalpinx chamaelepanthes | Ecuador | |||
| Trichosalpinx dirhampis | Ecuador | |||
| Trichosalpinx escobarii | Ecuador | |||
| Trichosalpinx memor | Ecuador | |||
| Trichosalpinx patula | Ecuador | |||
| Trichosalpinx pusilla | Ecuador | |||
| Trichosalpinx rabeii | Ecuador | |||
| Trichosalpinx semilunata | Ecuador | |||
| Trichosanthes kirilowii Maxim | China | |||
| Tridax procumbens L | Coat Buttons | aerial part | C-America | |
| Trifolium arvense L | Hare's Foot Clover | herb | W-Europe | |
| bio | Trifolium pratense L | Red Clover | flower | SE-Europe |
| Trigonella foenum-graecum L | Fenugreek | |||
| Trigonidium acuminatum | Ecuador | |||
| Trigonidium egertonianum | Ecuador | |||
| Trigonidium grande | Ecuador | |||
| Trilisa odoratissima (Walter ex J F Gmel) Cass | Deer's Tongue Leaf | N-America | ||
| Trillium erectum L | Beth Root | root | N-America | |
| Trillium pendulum W (-> T erectum L) | ||||
| Triosteum perfoliatum L | ||||
| Trisetella andreettae | Ecuador | |||
| Trisetella cordeliae | Ecuador | |||
| Trisetella hirtzii | Ecuador | |||
| Trisetella hoeijeri | Ecuador | |||
| Trisetella nodulifera | Ecuador | |||
| Trisetella regia | Ecuador | |||
| Trisetella strumosa | Ecuador | |||
| Trisetella triglochin | Ecuador | |||
| Triticum aestivum L | Wheat | |||
| Triticum repens L (-> Elymus repens (L) Gould subsp Repens) | ||||
| Triticum sativum Lam (-> T aestivum L subspAestivum) | Wheat | |||
| Tropaeolum majus L | Garden nasturtium | |||
| Tsuga canadensis (L) Carrière | Canadian hemlock | |||
| Tulbaghia violacea Harv | Wild Garlic | herb | S-Africa | |
| Turbinicarpus alonsoi | America | |||
| Turbinicarpus beguinii(Turbinicarpus mandragora) | America | |||
| Turbinicarpus flaviflorus(T schmiedickeanus) | America | |||
| Turbinicarpus gielsdorfianus | America | |||
| Turbinicarpus lilinkeuideuus | America | |||
| Turbinicarpus macrochele(Turbinicarpus schmiedickeanus) | America | |||
| Turbinicarpus pseudomacrochele | America | |||
| Turbinicarpus swobodae | America | |||
| Turbinicarpus valdezianus | America | |||
| Turnera aphrodisiaca G H Ward (-> T diffusa Willd var aphrodisiaca (G Hherb powder | Damiana | Ward) Urb) | N-America | |
| Turnera diffusa Willd | Damiana | leaf | C-America | |
| Turnera diffusa Willd var aphrodisiaca (G H Ward) Urb | Damiana | C-America | ||
| Turnera scabra Millsp | Rough Yellow Alder | leaf | C-America | |
| Tussilago farfara L | Coltsfoot | China | ||
| Tylophora asthmatica (L f) Wight & Arn (-> T indica (Burm f) Merr) | ||||
| Tylophora indica (Burm f) Merr | ||||
| Typha angustifolia L | ||||
| Typha angustifolia L / Typha orientalis Presl | China | |||
| Typhonium giganteum Engl | China |
