4,295 articles
Rapeseed
Rapeseed (Brassica napus, B. rapa, B. juncea), also called colza or canola when low-erucic, is a major oilseed: ~42% oil, second most produced edible oil, meal 36-38% protein, industrial erucic-acid uses.
Rapeseed oil
Rapeseed oil (canola oil, from Canadian oil, low acid) is oil from Brassica napus and related seeds, bred below 2% erucic acid; global production about 37 million metric tons, used for food, feed, and biofuel.
Raphanus
Raphanus (radish genus), Brassicaceae tribe Brassiceae; includes Raphanus sativus (radish) and R. raphanistrum (wild radish); shown polyphyletic, with sect. Hesperidopsis proposed as genus Quidproquo.
Raphanus raphanistrum
Raphanus raphanistrum (wild radish, jointed charlock), a Brassicaceae annual native to Europe through Central Asia and ancestor of the cultivated radish; a major Australian crop weed with widespread multiple herbicide resistance and seeds viable up to 20 years.
Rapini
Rapini, also called broccoli rabe or broccoli raab, is a bitter green vegetable in the mustard family, a turnip relative grown for its leaves, stems, and small unopened buds.
Rare and threatened bryophytes of the British Isles
The rare and threatened bryophytes of the British Isles are mosses, liverworts, and hornworts assessed on British and Irish red lists, with 191 British species threatened in 2023.
Raspberry
Raspberry (Rubus idaeus, European red raspberry) is a Rosaceae shrub whose fruit is an aggregate of drupelets, hollow when picked. Native to temperate Eurasia and North America; bee-pollinated; Russia led 2024 production with 213,818 tonnes.
Ratibida columnifera
Ratibida columnifera, upright prairie coneflower or Mexican hat, is a native Great Plains perennial forb in Asteraceae with a columnar flower disk, yellow to maroon rays, used in prairie restoration.
Rattan
Rattan (Malay rotan): about 600 spiny climbing palm species of the Old World tropics, mainly Calamus, whose solid flexible stems (cane) supply furniture and basketry; Southeast Asia's top forest product after timber.
Rauvolfia serpentina
Rauvolfia serpentina (Indian snakeroot, sarpagandha), an Apocynaceae shrub of South Asia whose reserpine-rich roots were major antihypertensive and sedative drugs; endangered by over-exploitation.
Ravenala
Ravenala, the traveller's palm or ravinala, is a Madagascan genus of Strelitziaceae; once monotypic with R. madagascariensis, it gained five new species in 2021 and is lemur-pollinated with blue-seeded arils.
Red algae
Red algae (Rhodophyta) are mostly marine multicellular seaweeds, about 7,276 described marine species, colored by phycobiliprotein pigments, lacking flagellated cells, and the source of agar and carrageenan.
Red banana
The red banana, also known as Red Dacca, is a dessert banana cultivar of Musa acuminata with reddish-purple peel, shorter and plumper than Cavendish, and often sweeter.
Red cabbage
Red cabbage (Brassica oleracea var. capitata f. rubra) is a purple-leaved head cabbage rich in anthocyanins, used as a natural pH indicator, food colorant, and smart-packaging freshness sensor, with more glucoraphanin and vitamin C than white cabbage.
Red Delicious
Red Delicious is a major American apple cultivar, also called Stark Delicious or Hawkeye, a chance seedling found by Jesse Hiatt in Peru, Iowa, commercialized by Stark Bro's after winning the 1894 fruit show, later reshaped by red-color bud sports.
Red kiwifruit
Red kiwifruit: kiwifruit with red anthocyanin flesh, mainly Actinidia chinensis cultivars such as Hongyang, Donghong, and Zespri RubyRed (Red19, Red80), plus red kiwiberries like Hardy Red and Ken's Red.
Red onion
Red onion, a red- or purple-skinned cultivar group of Allium cepa (bulb onion), rich in anthocyanins and sulfur compounds; eaten raw in salads and pickles, pricier than yellow or white onions.
Red rice
Red rice: rice (Oryza sativa) with a red pericarp from proanthocyanidins, governed by the Rc gene; eaten as an unpolished food in Asia and Africa, and in the US a name for weedy rice descended from crop-wild hybrids.
Redcurrant
Redcurrant (Ribes rubrum L.) is a western European Grossulariaceae shrub bearing translucent red berries in clusters; white and pink currants are its variants. Domesticated from the 1400s, Dutch-bred, grown for juice, jam, and wine.
Regional bryophyte checklist
A regional bryophyte checklist summarizes the mosses, liverworts, and hornworts of a country, province, or group of countries, based on traceable herbarium specimens; Europe's 2019 checklist counts 1,892 species.
Regional distribution of Polytrichaceae
The Polytrichaceae, or haircap mosses, are a family of about 200 to 260 species in 17 to 22 genera, found in all climatic zones except the lowland tropics.
Regional distribution of Pteridaceae
Pteridaceae, the maidenhair and brake fern family, is a near-cosmopolitan family of roughly 1,000 to 1,200 species, most diverse in the tropics and deserts, with Brazil holding 207 species.
Regional fern floras
Regional fern floras are systematic written treatments of the fern and lycophyte species of a defined area, summarizing their classification, distribution, and endemism so plants can be identified.
Rehmannia glutinosa
Rehmannia glutinosa (地黄, dihuang, Chinese foxglove) is a Chinese perennial herb whose tuberous root, used fresh, dried, or steamed, is a major traditional medicine; over 310 constituents including catalpol are documented.
Reseda
Reseda (mignonette genus, Resedaceae), about 65 Old World species centered on the Mediterranean; includes weld (R. luteola), the historic luteolin yellow dye plant, and fragrant R. odorata.
Resedaceae
Resedaceae, the mignonette family (type genus Reseda), is a small Brassicales family of herbs and shrubs producing glucosinolates, centered on the Mediterranean, with 6 traditional genera and about 60 species, 11 genera in modern circumscriptions.
Resin acid
Resin acids are tricyclic C20 diterpene monocarboxylic acids (C19H29COOH, MW 302) of abietane and pimarane skeletons that make up rosin, conifers' stored chemical defense.
Restionaceae
Restionaceae (restios), family of wind-pollinated, mostly dioecious perennial herbs of the Southern Hemisphere; 51 genera, 572 species per Kew; dominant in Cape fynbos and Australian kwongan; flowers year-round with spring peak.
Retrophyllum
Retrophyllum is a genus of six (or five) dioecious podocarp conifers with twisted, comb-like flattened leaves and red drupe-like seed cones, disjunctly distributed in South America and Australasia, with fossils from the Late Cretaceous to Miocene.
Reynoutria
Reynoutria Houtt. (1777), knotweed genus of Polygonaceae, native Russian Far East to East Asia; includes Japanese knotweed (R. japonica); synonymy with Fallopia disputed, molecular data support separate status.