3,306 articles
Pyracantha coccinea
Pyracantha coccinea, scarlet firethorn (buisson ardent), a thorny evergreen Rosaceae shrub native from southern Europe to Iran, grown for white flowers and red berries, invasive in Florida, Brazil, and South Africa.
Pyrola
Pyrola (wintergreens) is a genus of about 42 accepted evergreen herbs in Ericaceae, tribe Pyroleae, native to subarctic and temperate Northern Hemisphere to Guatemala and Sumatera; Asian origin, dust-seed mycoheterotrophy, and use as the Chinese medicine Luxiancao distinguish it.
Pyrus
Pyrus is the pear genus of Rosaceae, native to temperate Eurasia and NW Africa, with about 77 accepted species, Occidental and Oriental clades, and independently domesticated European and Asian pears.
Pyrus calleryana
Pyrus calleryana, Callery or Bradford pear, is an Asian Rosaceae tree native to China, Korea, Japan, Taiwan, and Vietnam, planted ornamentally in the US since the early 1900s and now invasive there because cultivar cross-pollination yields viable, bird-dispersed seed.
Pyrus communis
Pyrus communis, the European pear, is a Rosaceae tree native from Europe to northern Iraq, domesticated separately in Europe and the Caucasus, fifth most produced fruit worldwide, with cultivars like Bartlett and Bosc.
Quarantine and biosecurity for conifer pests
Quarantine and biosecurity for conifer pests are the laws, inspections, surveillance, and eradication responses that stop non-native insects and pathogens from entering conifer forests through trade.
Quechua
Quechua (Salazar & L.Jost) is a monotypic Andean orchid genus in subtribe Spiranthinae, described in 2012, with the single lithophytic species Quechua glabrescens, formerly Spiranthes glabrescens, known from Ecuador and Peru.
Quercus
Quercus (oaks), genus of Fagaceae trees and shrubs with 400-450 species across the northern hemisphere, defined by acorns; fossil record from about 55 Ma, with Mexico and East Asia as diversity centers.
Quercus acutissima
Quercus acutissima, the sawtooth oak (Japanese kunugi), is a deciduous oak native from the Himalaya to Korea and Japan, with bristle-tipped leaf teeth and biennial acorns.
Quercus alba
Quercus alba, white oak (stave oak), a large long-lived deciduous oak of eastern North America with rounded-lobed leaves, barrel-grade wood, and declining young age classes since 1988.
Quercus cerris
Quercus cerris, Turkey oak (Saçlı Meşe), a fast-growing deciduous oak of section Cerris native to S. Europe to Türkiye and Anti-Lebanon; two-year acorns, bristly cups, drought-tolerant, IUCN least concern.
Quercus coccinea
Quercus coccinea, scarlet oak (also Spanish oak), an eastern US red oak of dry upland soils, 50-80 ft tall, with C-shaped leaf sinuses, scarlet fall color, thin fire-susceptible bark, and vigorous postfire sprouting; state tree of Washington, DC.
Quercus douglasii
Quercus douglasii, the blue oak (also iron oak, mountain white oak), is a drought-deciduous California endemic oak dominating foothill woodlands around the Central Valley; IUCN Least Concern, but low recruitment and projected range loss under climate change concern conservationists.
Quercus ilex
Quercus ilex, holm or holly oak, an evergreen Mediterranean oak of Fagaceae, dominant in dehesa woodlands; over 2 million ha, two subspecies (ilex, ballota), low-rate hybridization with cork oak, drought-tolerant anisohydric physiology.
Quercus nigra
Quercus nigra (water oak, possum oak) is a fast-growing red-group oak of the southeastern US Coastal Plain and bottomlands, with spatulate leaves, small biennial black acorns, weak wood, and wide use as a southern street tree.
Quercus palustris
Quercus palustris, the pin oak (also swamp oak, water oak), is a fast-growing red oak of eastern North American bottomlands, 50–70 ft tall, requiring acid soil and developing iron chlorosis on alkaline sites.
Quercus petraea
Quercus petraea, the sessile or durmast oak, is a large European oak native to Europe and N. Iran, distinguished from Q. robur by stalkless acorns and long leaf stalks, drought-tolerant, and valued for timber and barrels.
Quercus pubescens
Quercus pubescens (downy oak, pubescent oak), a polymorphic European white oak with hairy leaves and twigs, native from France to Türkiye, xerophilous on chalky soils, hybridizing with Q. petraea and Q. robur.
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.
Quisqueya
Quisqueya (pronounced kwiss-KWAY-ah) is a genus of four orchid species in Laeliinae, endemic to Hispaniola (Dominican Republic and Haiti), described by Donald Dod in 1979 with type species Q. karstii.
Raffia palm
Raffia palm (Raphia, jupatí, wine palm): massive African wetland palms yielding raffia and piassava fiber, palm wine, thatch, and food; monocarpic, with the largest leaves in the plant kingdom and about 100 recorded uses.
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.
Ragweed
Ragweed (Ambrosia, Asteraceae), including common ragweed Ambrosia artemisiifolia, is a North American wind-pollinated weed whose highly allergenic pollen causes hay fever; it invaded Europe via multiple introductions and contaminated grain, costing billions annually.