881 articles
Toxicodendron diversilobum
Toxicodendron diversilobum, western or Pacific poison oak, is a deciduous Anacardiaceae shrub or vine native from British Columbia to northern Mexico whose urushiol oil causes allergic contact dermatitis in 10 to 50 million Americans yearly.
Toxicodendron radicans
Toxicodendron radicans, eastern poison ivy (formerly Rhus radicans), is a North American Anacardiaceae vine or shrub with three leaflets whose urushiol causes allergic contact dermatitis in most people.
Toxicodendron vernix
Toxicodendron vernix (poison sumac, swamp sumac, thunderwood), basionym Rhus vernix, is a wetland Anacardiaceae shrub of eastern North America with 7-13 leaflets on red stalks and urushiol in all parts causing allergic contact dermatitis.
Trapa
Trapa (water caltrop, water chestnut) is a genus of annual floating-leaved aquatic plants in Lythraceae, native to the Old World, with 8 accepted species, starchy edible horned fruits, and invasive populations in North America.
Trema
Trema Lour. is a pantropical genus of pioneer trees and shrubs in Cannabaceae, published in 1790, with about 20 species (including Parasponia), 3-veined serrate leaves, and small hard-endocarp drupes.
Triadica
Triadica Lour. (Euphorbiaceae), a three-species Asian tree genus including Chinese tallow (Triadica sebifera), source of vegetable tallow and stillingia oil and invasive in the southeastern United States.
Tribulus terrestris
Tribulus terrestris, or puncture vine, is a spiny-fruited herb used in traditional Chinese and Indian medicine and sold as a supplement, though trials show it does not raise testosterone.
Trifoliate orange (枳)
Trifoliate orange (枳, karatachi), Citrus trifoliata, formerly Poncirus trifoliata, is a deciduous thorny Chinese citrus relative, the hardiest citrus, used worldwide as a cold-hardy, disease-tolerant semi-dwarfing rootstock and in citrus hybrid breeding.
Trifolium alexandrinum
Trifolium alexandrinum, known as berseem or Egyptian clover, is an annual forage legume grown as a winter feed crop in the Nile Valley and northern India.
Trifolium hybridum
Trifolium hybridum, alsike clover, is a short-lived perennial forage legume in Fabaceae, native from the Mediterranean to Iran, adapted to wet acidic soils, causing bloat and photosensitization, and not a red-white clover hybrid.
Trifolium pratense
Trifolium pratense (red clover, purple clover, rotklee) is a short-lived perennial forage legume in Fabaceae, native to Europe and western Asia, grown for high-protein feed and nitrogen fixation, second only to lucerne among sown forage legumes.
Trifolium repens
Trifolium repens, white or Dutch clover, is a stoloniferous perennial Fabaceae legume of Europe and the Mediterranean, grown worldwide for forage, nitrogen fixation, honey, and pollinator lawns.
Trifolium subterraneum
Trifolium subterraneum, subterranean clover or subclover, an annual Mediterranean pasture legume (Fabaceae) with three subspecies (subterraneum, yanninicum, brachycalycinum) that buries its seed pods underground, enabling self-regeneration in grazed pastures, notably in southern Australia.
Triplochiton
Triplochiton K.Schum. is a genus of two African timber trees in Malvaceae (Helicteroideae), including T. scleroxylon, the obeche or ayous whitewood, conserved against Triplochiton Alef. 1863.
Tripterygium
Tripterygium, East Asian Celastraceae vines including Thunder God Vine (Tripterygium wilfordii), source of triptolide and celastrol; potent anti-inflammatory, immunosuppressive extracts with narrow therapeutic window and hepatotoxic, reproductive toxicity.
Tropaeolum
Tropaeolum, the nasturtium genus (nasturtiums, Indian cress), is a Brassicales genus of 93 accepted species in Tropaeolaceae, native from Mexico to southern South America; includes garden nasturtium T. majus and the Andean tuber crop mashua.
Turnera
Turnera is a genus of about 120 to 145 flowering plants in the family Passifloraceae, native chiefly to tropical America and the source of the herb damiana.
Turnera diffusa
Turnera diffusa (damiana), a Passifloraceae shrub native from southern Texas to Brazil, is a traditional herbal tea plant reputed as an aphrodisiac, with flavonoid-rich leaves, licensed Canadian products, and German FSIAD therapy use.
Uapaca
Uapaca (sugar plum genus) is a Phyllanthaceae genus of dioecious African and Madagascan trees; U. kirkiana, the miombo sugar plum, is a prized edible-fruit and timber tree of southern Africa.
Uapaca guineensis
Uapaca guineensis (rikio, sugar plum) is a West and Central African Phyllanthaceae tree of wet tropical forests, used for local construction timber, raw edible fruit, and traditional medicine; IUCN least concern.
Ugni
Ugni (uñi) is a genus of four accepted Myrtaceae shrub species native from Mexico to southern South America; Ugni molinae, the Chilean guava or murtilla, is a cultivated Patagonian berry, distinct from Myrtus and from Amomyrtus luma.
Ulex
Ulex (gorse, furze, whin) is a genus of spiny, yellow-flowered Fabaceae shrubs native to western Europe and the Mediterranean, with about 15-21 species, a diploid-tetraploid-hexaploid series, and the invasive hexaploid Ulex europaeus spread across more than 50 countries.
Ulex europaeus
Ulex europaeus, known as gorse, furze, or whin, is a spiny evergreen shrub of the legume family, native to western Europe and among the world's worst invasive plants.
Ulmaceae
Ulmaceae (elm family), Ulmaceae Mirb. 1815, a Rosales family of trees and shrubs with distichous unequal-sided leaves and samara or drupe fruits; about 7 genera, 40–60 species, split from Cannabaceae, temperate and tropical clades.
Ulmus minor
Ulmus minor, field elm or smooth-leaved elm (olmo), a deciduous Ulmaceae tree native from Europe to Central Asia and NW. Africa; riparian pioneer to 20 m, devastated by Dutch elm disease (Ophiostoma), IUCN Data Deficient, with two accepted subspecies.
Ulmus pumila
Ulmus pumila, the Siberian elm (also called littleleaf, dwarf, or Chinese elm), is a fast-growing, drought- and frost-hardy Asian elm, resistant to Dutch elm disease, used in breeding and windbreaks, and invasive in North America.
Ulmus rubra
Ulmus rubra Muhl., slippery elm (also red elm, gray elm, soft elm), a medium-sized deciduous North American elm of Ulmaceae, named for mucilage in its inner bark used in throat lozenges; threatened by Dutch elm disease.
Urena lobata
Urena lobata (Caesar's weed, Congo jute, aramina) is a pantropical Malvaceae subshrub grown for jute-like bast fiber, used medicinally, and invasive in Florida and the Philippines.
Urtica
Urtica (nettles), genus of stinging-haired herbs in Urticaceae, Rosales, first published 1753; about 50-69 accepted species, subcosmopolitan except Antarctica; includes U. dioica and U. urens, used as food and medicine.
Urtica dioica
Urtica dioica, stinging nettle, common nettle: a dioecious rhizomatous perennial herb of Urticaceae native from Europe to Siberia and NW Africa, with silica-mineralized stinging hairs injecting histamine and acetylcholine, used as food, fiber, and herbal medicine.