Seed plants

Tulipa sylvestris

Tulipa sylvestris, the wild tulip, is a small yellow fragrant tulip (Liliaceae) native to the Mediterranean. Introduced to northern Europe from Bologna and Montpellier in the 1550s–1570s, it is the only tulip growing wild there, with diploid subsp. australis and tetraploid subsp. sylvestris.

Turmeric

Turmeric (Curcuma longa) is a perennial herb of the ginger family whose rhizomes are ground into a bright yellow spice used in South Asian cuisine and medicine.

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.

Turpentine

Turpentine (spirit of turpentine, oil of turpentine, CAS 8006-64-2) is a pine-resin distillate of terpenes used as a solvent and camphor/menthol feedstock; flammable, 100 ppm exposure limit, once a major naval store.

Tussilago

Tussilago, coltsfoot (Tussilago farfara), a monotypic Asteraceae genus of temperate Eurasia; cough remedy and vegetable containing hepatotoxic pyrrolizidine alkaloids, invasive in North America.

Typha angustifolia

Typha angustifolia (narrowleaf cattail, lesser reed mace) is a temperate Northern Hemisphere emergent wetland perennial with narrow leaves and a 2-12 cm gap between male and female spike portions; invasive in North America and parent of the hybrid Typha x glauca.

Typha domingensis

Typha domingensis, southern cattail or Santo Domingo cattail, is a rhizomatous Typhaceae wetland helophyte native to tropics and subtropics worldwide, tolerant of brackish water, and widely used in constructed wetlands for wastewater phytoremediation.

Typhaceae

Typhaceae (cattail family), Juss. 1789, a Poales family of two aquatic genera, Typha (cattails) and Sparganium (bur-reeds), wind-pollinated wetland herbs with dense cylindrical spikes, Cretaceous fossils, and invasive Typha in North America.

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.

Ug99

Ug99 (race TTKSK) is a virulent strain of wheat stem rust, Puccinia graminis f. sp. tritici, found in Uganda in 1998-1999; it overcame Sr31 and Sr38 resistance, spread through Africa, the Middle East, and Nepal, and prompted the Borlaug Global Rust Initiative.

Ugali

Ugali (posho, sima) is the stiff maize-flour porridge that is the daily staple of Kenya, Tanzania, and Uganda, eaten by hand with vegetables or meat; it replaced older sorghum and millet porridges after maize arrived in Africa in the 16th-17th centuries.

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.

Ullucus

Ullucus (ulluco, melloco, papalisa; Ullucus tuberosus Caldas), sole species of its Basellaceae genus, is an Andean tuber crop grown at 2,600–3,800 m, notable for betalain pigments absent in other Andean tubers and for Ecuador's second-most-important tuber after potato.

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 americana

Ulmus americana, the American elm (also white elm), is a deciduous tree of eastern North America prized for its vase-shaped crown and now endangered, largely from Dutch elm disease.

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.

Umbilicus

Umbilicus (navelworts) is a genus of about 12 succulent Crassulaceae herbs with peltate, navel-marked basal leaves and urn-shaped flowers, native from Macaronesia and Europe to Iran, Arabia, and Tanzania.

Uncaria

Uncaria (gouteng, cat's claw) is a pantropical genus of about 38 climbing Rubiaceae lianas with claw-like hooks, rich in indole alkaloids and widely used in traditional medicine.

Uncaria gambir

Uncaria gambir (gambier, pale catechu) is a climbing Rubiaceae shrub native to western Malesia, cultivated in Indonesia and Malaysia; its leaf-and-twig extract is used for betel chewing, tanning, and traditional medicine.

Uncinia

Uncinia Pers., a former genus of about 70 hooked-rachilla sedges in tribe Cariceae (Cyperaceae), merged into Carex in 2015 as Carex subg. Uncinia; Southern Hemisphere, allopolyploid origin.

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.

Urochloa

Urochloa (syn. Brachiaria) is a pantropical African-centred grass genus whose species, including U. brizantha, U. decumbens, U. humidicola, and U. ruziziensis, are major apomictic polyploid tropical pasture forages covering over 100 million hectares in Brazil.

Urochloa brizantha

Urochloa brizantha, long known as Brachiaria brizantha and commonly called palisade grass, is a perennial tropical forage grass native to Africa, widely cultivated as pasture, especially in Brazil.