4,295 articles
Oak
Oak (Quercus, Fagaceae): about 425 species of acorn-bearing trees and shrubs of the temperate Northern Hemisphere, wind-pollinated, prone to hybridization yet genetically distinct, vital to wildlife and timber.
Oat
Oat (Avena sativa), a hexaploid cereal grass of Poaceae, sixth in world cereal production; a secondary crop domesticated from weed in Near East wheat and barley fields, grown in cool moist climates and valued for cholesterol-lowering beta-glucan fiber.
Oat beta-glucan
Oat beta-glucan is the water-soluble, mixed-linkage fiber in oat cell walls that lowers LDL cholesterol and blood glucose, backing approved heart-health claims for intakes of about 3 g per day.
Oat diseases and pests
Oat diseases and pests are the biotic constraints on cultivated oat yield, dominated by crown rust and barley yellow dwarf virus, which can cut yields by up to 80%.
Oat milk
Oat milk, a plant-based beverage made from oats and water, was invented in the early 1990s by Rickard Öste at Lund University and commercialized by Oatly (founded 1994); enzyme hydrolysis, low protein, beta-glucan fiber, and barista coffee use distinguish it.
Oat protein
Oat protein (Avena sativa), also called oat protein isolate or concentrate, is a plant protein whose major storage fraction is 12S globulin; it is hypoallergenic, mildly flavored, and limited by low neutral-pH solubility.
Oatmeal
Oatmeal: ground, steel-cut, or rolled hulled oats (Avena sativa groats) and the porridge made from them. Types differ in processing, cooking time, and glycemic index; beta-glucan fiber supports its heart-health claims.
Oceaniopteris
Oceaniopteris is a genus of ferns in the family Blechnaceae, erected in 2016 to hold species formerly placed in Blechnum; its species are found mainly in Oceania.
Ochnaceae
Ochnaceae DC. (including Medusagynaceae and Quiinaceae) is a conserved pantropical family of Malpighiales: about 500-550 species, 30-37 genera of evergreen trees and shrubs with stipules, yellow petals, and superior ovaries.
Ochroma
Ochroma (balsa tree, Ochroma pyramidale) is a monotypic Malvaceae genus native from S. Mexico to tropical America. Its wood, 60–380 kg/m³, is the lightest commercial timber, used in sandwich panels; Ecuador supplies 80–90% of trade.
Ocimum
Ocimum (basil genus), Lamiaceae mint family, pantropical aromatic herbs and shrubs named by Linnaeus in 1753; about 65 species mostly African, including sweet basil (O. basilicum) and holy basil (O. tenuiflorum), valued for terpenoid and phenylpropanoid essential oils.
Ocimum gratissimum
Ocimum gratissimum (clove basil, African basil, ram/Vana tulsi) is a Lamiaceae aromatic shrub of the Old World tropics, grown for eugenol- or thymol-rich essential oil with multiple chemotypes, used in food, medicine, ritual, and as an insect repellent.
Ocimum tenuiflorum
Ocimum tenuiflorum, holy basil or tulsi (तुलसी), synonym Ocimum sanctum, is a Lamiaceae perennial herb native to tropical Asia, sacred in Hinduism, rich in eugenol and ursolic acid, and studied in stress and metabolic clinical trials.
Oedipodium
Oedipodium, or gouty-moss (Oedipodium griffithianum), is the sole species of the moss family Oedipodiaceae and class Oedipodiopsida, a peristome-less acrocarpous moss placed basal to peristomate mosses, with disjunct Northern Hemisphere and Tierra del Fuego populations.
Oenothera
Oenothera (evening primroses) is a New World genus of about 140-156 herbaceous species in Onagraceae, famous as de Vries's mutation-theory plant, with biparental chloroplast inheritance, Renner complexes, and seed oil rich in gamma-linolenic acid.
Oenothera biennis
Oenothera biennis, the common evening primrose, is a biennial herb native to North America with bright yellow flowers that open at night, grown as the source of evening primrose oil.
Oklahoma city university herbarium
The Oklahoma City University Herbarium (OCU) is a plant specimen collection at Oklahoma City University, curated by botanist Adam Ryburn, with about 1,700 digitized records shared through the TORCH consortium and iDigBio.
Okra
Okra (Abelmoschus esculentus, lady's finger, gumbo, bamya, bhendi) is a tropical mallow grown for mucilaginous pods; 11.5 Mt in 2023, led by India, Nigeria, and Mali.
Olacaceae
Olacaceae (R.Br. 1818, nom. cons.) is a pantropical family of Santalales with trees, shrubs, and climbers, about 25-29 genera and roughly 250 species; traditionally circumscribed Olacaceae is paraphyletic and has been split into narrower families including Erythropalaceae and Strombosiaceae.
Old Tjikko
Old Tjikko is a Norway spruce (Picea abies) located on Fulufjället, Dalarna Province, Sweden. Its root system is dated to about 9,500 years, making it a notable living clone.
Olea
Olea is a genus of about 32 evergreen Oleaceae trees and shrubs of the Old World, including the olive Olea europaea with six subspecies, over 1,000 cultivars, and the wild oleaster var. sylvestris.
Oleaceae
Oleaceae, the olive family (Hoffmanns. & Link, 1809), is a family of Lamiales with 25-27 genera and c. 600-615 species of trees, shrubs, and woody climbers, including Olea europaea, Fraxinus, Jasminum, and Syringa, recognized by opposite estipulate leaves and 4-merous flowers with 2 stamens.
Olearia
Olearia (daisy bush), genus of evergreen Asteraceae shrubs and small trees, about 180 species in Australia, New Zealand, and New Guinea; shown polyphyletic since 2002 and being split into Shawia and other genera.
Olein
Olein is the liquid fraction obtained when palm oil or another vegetable oil is fractionated from its solid stearin, used in cooking oils and margarine.
Olive
Olive (Olea europaea), Mediterranean evergreen tree of Oleaceae cultivated for table fruit and olive oil; wild form is the oleaster. Levant domestication from Chalcolithic times, alternate bearing, oleuropein bitterness, Xylella threat.
Olive oil
Olive oil, the oil pressed from Olea europaea fruit, graded extra virgin (free acidity ≤0.8%), virgin, refined, or pomace by IOC and USDA standards; EU produces ~67% of world supply; UC Davis studies found many imported "extra virgin" oils fail standards.
Oliveriana
Oliveriana Rchb.f. is a genus of 15 accepted Oncidiinae orchid species native from western South America to Guyana, named for botanist Daniel Oliver; type species O. egregia, described 1876.
Omacetaxine mepesuccinate
Omacetaxine mepesuccinate (Synribo), formerly homoharringtonine, is a semisynthetic cephalotaxine protein synthesis inhibitor binding the 80S ribosome, FDA-approved October 26, 2012 for CML resistant or intolerant to two or more tyrosine kinase inhibitors, including T315I-mutant disease.
Omurice (オムライス)
Omurice (オムライス, omuraisu) is Japanese yoshoku comfort food: ketchup-seasoned chicken rice wrapped in a thin omelette. Origin claimed by Rengatei (Tokyo, c. 1900) and Hokkyokusei (Osaka, 1925); styles include ganso, fuwatoro, and Kichi Kichi's viral sliced-open version.
Onagraceae
Onagraceae, the evening primrose family (Onagraceae Juss., nom. cons., 1789), a Myrtales family of about 650 species in 22-23 genera, mostly New World herbs and shrubs with 4-merous flowers, inferior ovaries, and viscin-threaded pollen; includes Oenothera, Fuchsia, Clarkia, Epilobium, Ludwigia.