881 articles
Quercus robur
Quercus robur (English or pedunculate oak), a 20-40 m Fagaceae tree native from Europe to Iran, Britain's iconic oak, hybridizing with Q. petraea, timber for ships and Westminster Hall, IUCN Least Concern.
Quercus rubra
Quercus rubra, northern red oak (dąb czerwony, chêne rouge), a large deciduous oak native to eastern North America, introduced to Europe in 1691; fast-growing timber and ornamental tree, drought-tolerant, invasive in Central Europe, susceptible to oak wilt.
Quercus stellata
Quercus stellata, post oak or iron oak, a slow-growing white oak of the southeastern and south-central US, drought-resistant on dry uplands, living 300-400 years, with fencepost wood and Cross Timbers pure stands.
Quercus suber
Quercus suber, the cork oak, is an evergreen oak of the western and central Mediterranean whose bark is stripped periodically and regrown, chiefly for wine stoppers.
Quercus variabilis
Quercus variabilis (栓皮栎), the Chinese cork oak or oriental oak, is an East Asian deciduous oak to 30 m with thick corky bark, cork and tannin uses, IUCN Least Concern status, and a 787 Mb genome.
Quercus velutina
Quercus velutina, black oak or yellow oak, is a deciduous eastern North American red oak of dry upland slopes, with black furrowed bark, yellow bitter inner bark (quercitron dye), biennial acorns, and wood sold as red oak.
Quercus virginiana
Quercus virginiana, the southern live oak (Virginia live oak), is a nearly evergreen southeastern US coastal plain oak with crowns to 150 ft, extremely dense wood used in USS Constitution shipbuilding, high salt tolerance, and G5/LC conservation status.
Rafflesia
Rafflesia, the corpse flower genus (Rafflesiaceae), is a Southeast Asian holoparasite on Tetrastigma vines with no leaves, stems, or roots; R. arnoldii bears the world's largest single flower, up to 1 m and 7 kg, smelling of rotting meat.
Rafflesia arnoldii
Rafflesia arnoldii (corpse flower, padma raksasa) is a holoparasitic Sumatran and Bornean plant on Tetrastigma vines, producing the world's largest single flower, up to 1 m across, smelling of rotting meat and pollinated by carrion flies.
Rambutan
Rambutan (Nephelium lappaceum, Vietnamese Chom Chom, Thai Ngo) is a Sapindaceae tropical tree from southern China to Malesia with hairy red fruit, sweet aril, 1.4 Mt annual Southeast Asian production, Indonesia largest producer.
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 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.
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.
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.
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.
Rhamnaceae
Rhamnaceae, the buckthorn family, is a Rosales family of trees, shrubs, and vines with c. 50-60 genera and 900-1,200 species, cosmopolitan, including Ziziphus jujubes, Rhamnus buckthorns, and Ceanothus ornamentals.
Rhamnus (plant)
Rhamnus (buckthorn) is a genus of about 139 accepted species of shrubs and small trees in Rhamnaceae, native to temperate and subtropical to tropical mountains, with drupes bearing 2-4 stones; R. cathartica is invasive in eastern North America.
Rhamnus alaternus
Rhamnus alaternus (Italian buckthorn, evergreen buckthorn) is a Mediterranean evergreen Rhamnaceae shrub, dioecious, with black 3-stoned drupes; used in North African folk medicine and invasive in California, Australia, and New Zealand.
Rhizophora apiculata
Rhizophora apiculata (kongkang) is an Indo-West Pacific mangrove tree of Rhizophoraceae, dominant on estuarine mud from South Asia to Queensland, parent of two hybrids, used for charcoal and wood, IUCN Least Concern.
Rhizophora mangle
Rhizophora mangle, the red mangrove, is a viviparous stilt-rooted evergreen tree of tropical intertidal coasts of America and West Africa, tolerating 0-90 ppt salinity, IUCN Least Concern, invasive in Hawaii and Queensland.
Rhizophora mucronata
Rhizophora mucronata, Asiatic or loop-root mangrove (Rhizophoraceae), is a viviparous Indo-Pacific mangrove tree to 25 m with stilt roots and pointed leaves; bark yields tannin, parts serve traditional medicine, and it is IUCN Least Concern.
Rhizophoraceae
Rhizophoraceae, the red mangrove family, is a mainly Old World tropical family of 15–16 genera and about 145 species in Malpighiales, including about half of the world's true mangrove species.
Rhodiola rosea
Rhodiola rosea (rosenroot, arctic root, golden root), Crassulaceae succulent perennial of the subarctic Northern Hemisphere; root used traditionally as an adaptogen for stress and fatigue; EU traditional-use monograph; clinical evidence inconclusive; wild stocks overharvested.
Rhododendron ponticum
Rhododendron ponticum, an evergreen Ericaceae shrub native to the Black Sea region and Iberia, introduced to Britain in 1763, now one of the most destructive invasive plants of the British Isles, forming dense thickets and hosting Phytophthora ramorum.
Rhus typhina
Rhus typhina (staghorn sumac, Rhus hirta) is a suckering North American shrub or small tree of Anacardiaceae, 15-25 ft tall with velvety branches and red hairy fruit; harmless, unlike poison sumac (Toxicodendron vernix), and a 17th-century European introduction.
Ricinus
Ricinus, castor bean or castor oil plant (Ricinus communis L.), sole species of its Euphorbiaceae genus, native to NE tropical Africa, domesticated ~3200 years ago; seeds yield ricinoleic-acid-rich castor oil and the toxin ricin.
Robinia pseudoacacia
Robinia pseudoacacia, black locust or false acacia, is a fast-growing, nitrogen-fixing North American tree introduced to Europe in the early 17th century, widely planted for durable wood and honey yet ranked among Europe's 100 most invasive alien species.
Rosa bella
Rosa bella (美蔷薇, mei qiang wei) is a Chinese rose species, Rosaceae, described by Rehder & Wilson in 1915; a 1–3 m shrub of north and east China with pink flowers, red hips, and uses in oils, jam, and medicine.