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Tulip divisions
Tulip divisions are the 15 horticultural categories into which registered tulip cultivars are grouped by flower shape and, for the last four divisions, botanical origin, fixed since 1981.
Tulipa agenensis
Tulipa agenensis (eyeball tulip, Tulipe d'Agen) is an eastern Mediterranean wild tulip in Liliaceae, native from Cyprus and Palestine to Türkiye, naturalized in Greece and France, with 43 synonyms including T. oculus-solis and T. praecox.
Tulipa biflora
Tulipa biflora (two-flowered tulip, Tulipa polychroma synonym) is a small white-flowered bulbous geophyte in Liliaceae, native from the Balkans and Crimea to Egypt and Xinjiang, and the center of a polyphyletic species complex in subgenus Eriostemones.
Tulipa fosteriana
Tulipa fosteriana is a wild tulip species of the lily family, native from Central Asia to Afghanistan, and one of the two main wild ancestors of commercial cut-flower tulips.
Tulipa kaufmanniana
Tulipa kaufmanniana, the water lily tulip, is a Central Asian wild tulip described by Regel in 1877, with short stems, yellow-eyed cup-shaped flowers, and the early-flowering Kaufmanniana Group of garden cultivars; IUCN Near Threatened.
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.
Tumbleweed
Tumbleweed, chiefly Russian thistle (Salsola tragus), a spiny Eurasian annual whose dried spherical top breaks off and rolls in the wind, spreading seed; introduced to South Dakota in 1873 and now invasive across the western United States.
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.
Turnip
Turnip (Brassica rapa), biennial root vegetable of the mustard family grown for its white storage root and greens; domesticated in Central Asia 3,430–5,930 years ago, likely the first B. rapa crop type, later a European fodder staple.
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.
Types of tobacco
Types of tobacco: Virginia (flue-cured), Burley, Maryland, Oriental, fire-cured, and dark air-cured leaf of Nicotiana tabacum and N. rustica, defined by curing method, chemistry, legal categories, and use in cigarettes, cigars, pipe, and smokeless products.
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.
Ulkenia microalgal oil
Ulkenia microalgal oil, DHA-rich oil from the thraustochytrid Ulkenia sp. (strain SAM2179), about 45% DHA; GRAS in the US (GRN 319, 2010) and an authorized EU novel food.
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 'New Horizon'
Ulmus 'New Horizon' (New Horizon elm) is a Dutch elm disease resistant hybrid elm cultivar bred at the University of Wisconsin and released in the 1990s.
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 americana 'Princeton'
Ulmus americana 'Princeton', the Princeton American elm, is a 1922 Princeton Nurseries selection of pure American elm, later found resistant to Dutch elm disease and widely planted, including on the National Mall.