2,112 articles
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.
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.
Urtica urens
Urtica urens, the small or burning nettle, is an annual stinging herb up to 60 cm tall, native to the Old World and now almost cosmopolitan.
Urticaceae
Urticaceae, the nettle family (order Rosales), is a family of about 59 genera and roughly 2,100 to 2,600 species of herbs, shrubs, and trees, often with stinging hairs and cystoliths; includes Urtica, Boehmeria, Pilea, Elatostema, and the former Cecropiaceae.
Utricularia
Utricularia (bladderworts), largest carnivorous plant genus with 288 accepted species in Lentibulariaceae; rootless plants with millisecond suction bladder traps, cosmopolitan distribution, and dynamic 60-1500 Mb genomes.
Uvaria
Uvaria is a genus of about 170 accepted species of climbing or trailing shrubs in the custard-apple family Annonaceae, native to the tropical and subtropical Old World to Australia, used in traditional medicine and revised phylogenetically to absorb several former genera.
Vaccinium
Vaccinium L. is a cosmopolitan genus of about 450–500 berry-bearing shrubs in Ericaceae, tribe Vaccinieae, including blueberry, cranberry, and lingonberry; type species V. uliginosum, known to be polyphyletic.
Vaccinium angustifolium
Vaccinium angustifolium, the lowbush or wild blueberry, is a tetraploid Ericaceae subshrub native to eastern North America, harvested from managed wild stands in Maine and Atlantic Canada on a two-year prune-crop cycle, with higher anthocyanins than highbush blueberry.
Vaccinium macrocarpon
Vaccinium macrocarpon, American or large cranberry, Oxycoccus macrocarpus, a diploid Ericaceae vine native to eastern North American bogs, domesticated from 1810, USDA breeding from 1929, Wisconsin grows about 60 percent of the U.S. crop.
Vaccinium myrtillus
Vaccinium myrtillus, bilberry or European blueberry, is a wild Ericaceae subshrub of Eurasia and North America with anthocyanin-rich berries; rigorous trials do not support its night-vision and most supplement health claims.
Vaccinium vitis-idaea
Vaccinium vitis-idaea, lingonberry or cowberry, a circumpolar evergreen Ericaceae subshrub 5-15 cm tall with red 8-10 mm tart berries; two subspecies, ssp. minus in North America, ssp. vitis-idaea in Eurasia; IUCN least concern.
Vachellia
Vachellia is a pantropical genus of about 164 species of spiny trees and shrubs in the legume family, holding most former Acacia species outside Australia.
Vachellia nilotica
Vachellia nilotica, also called babul, prickly acacia, or Egyptian acacia (formerly Acacia nilotica), is a leguminous African-Asian tree used for medicine, gum, fodder, and tanning; its subspecies indica is a Weed of National Significance in Australia.
Valerian (herb)
Valerian (Valeriana officinalis), also called all-heal or garden heliotrope, is a European and Asian perennial whose roots are used as a herbal sedative for sleep and mild nervous tension, though clinical evidence of efficacy is inconsistent.
Valeriana locusta
Valeriana locusta L., also called Valerianella locusta, corn salad or lamb's-lettuce, is a small annual Caprifoliaceae herb native from Europe to the Caucasus and NW Africa, naturalized in North America and Asia, with tiny bluish flowers and corky-backed fruit.
Valerianella
Valerianella, commonly called cornsalad, is a genus of about 50 to 65 annual herb species in the family Caprifoliaceae, native to temperate regions of the northern hemisphere.
Vatica
Vatica (resak) is a genus of about 65 to 80 Dipterocarpaceae trees from Sri Lanka and India to New Guinea, with 79 accepted Kew species, fragrant 5-merous flowers, and timber traded as resak.
Vegetable oil
Vegetable oil: triglyceride liquid from plant seeds, nuts, or fruits (palm, soybean, canola, sunflower, olive). Refined for food, biofuels, lubricants; oxidation limits shelf life.
Vegetative reproduction
Vegetative reproduction (vegetative propagation): asexual plant reproduction from stems, roots, or leaves producing clones. Methods include stolons, rhizomes, tubers, bulbs, cuttings, grafting, layering, and micropropagation; used for potato, sugar cane, tulips, and fruit trees.
Venus flytrap
Venus flytrap (Dionaea muscipula), a carnivorous snap-trap plant native only to North and South Carolina wetlands; traps close in about one-tenth of a second after trigger hairs are touched twice, and the species was ruled not warranted for ESA listing in 2023.
Verbascum
Verbascum (mullein) is a genus of about 360 hairy herbs in Scrophulariaceae, native from Europe to Sri Lanka and Kenya, centered in Turkey and Iran, sister to Scrophularia, with Celsia and Rhabdotosperma as synonyms and V. thapsus the best-known medicinal species.