Plants and algae

Physalis peruviana

Physalis peruviana, the Cape gooseberry or goldenberry (uchuva, aguaymanto), is a Solanaceae herb of Andean South America grown for yellow berries in papery husks; Colombia produces about 90% of world output.

Physcomitrella patens

Physcomitrella patens, formally Physcomitrium patens (spreading earthmoss), a Funariaceae model moss; first bryophyte genome sequenced, highly efficient homologous recombination, moss bioreactor biopharmaceuticals, and 2022 ISS spore survival.

Phytolacca

Phytolacca (pokeweed, pokeroot, inkberry) is a genus of 27 accepted species in Phytolaccaceae, native to the Americas, Africa, Madagascar, and Asia; toxic, saponin-rich, with medicinal, dye, and molluscicidal uses.

Phytolacca americana

Phytolacca americana, American pokeweed or pokeberry, is a toxic perennial herb native to eastern North America, with black berry racemes, used as poke salad and ink, invasive in China and Europe.

Phytolaccaceae

Phytolaccaceae (pokeweed family), R.Br. 1818, nom. cons., a Caryophyllales flowering-plant family; broad sense 17 genera, 70–80 species, polyphyletic; strict sense Anisomeria, Ercilla, Phytolacca; type genus Phytolacca.

Phytoplankton

Phytoplankton (microalgae) are microscopic drifting photosynthetic organisms in fresh and salt water, including cyanobacteria, diatoms, dinoflagellates, and coccolithophores; they produce about half of Earth's oxygen and pump roughly 10 gigatonnes of carbon yearly into the deep ocean.

Phytotoxicity

Phytotoxicity, also called plant chemical injury, is the toxic effect of substances such as herbicides, pesticides, immature compost, or allelochemicals on plants, causing germination inhibition, chlorosis, necrosis, and stunted growth, measured by germination index bioassays and OECD plant tests.

Piccalilli

Piccalilli: a British pickle relish of onions, cauliflower, and cucumber in a turmeric-yellow mustard sauce, first recorded 1769 as piccalillo; in America the name covers chopped pepper, tomato, or chow-chow-style relishes.

Picea

Picea (spruce) is a genus of about 35–50 evergreen conifers in Pinaceae, native to Northern Hemisphere boreal and montane forests, defined by peg-like needle bases and pendulous cones; key species include Picea abies and P. sitchensis.

Picea abies

Picea abies, Norway spruce (gran, Épinette de Norvège), a large Pinaceae conifer native to the Alps, Balkans, Carpathians, and Scandinavia; Europe's key forestry spruce, widely transplanted since the 1500s, Least Concern but drought- and bark-beetle-vulnerable.

Picea breweriana

Picea breweriana, Brewer spruce or weeping spruce, a rare spruce endemic to the Klamath Mountains of southwest Oregon and northwest California, with pendulous ropelike branchlets, cones 8–15 cm, and basal position in the genus Picea.

Picea engelmannii

Picea engelmannii, Engelmann spruce (Columbian spruce, mountain spruce), a long-lived high-elevation conifer of the Rocky Mountains and Cascades from British Columbia to Arizona and New Mexico, typically codominant with subalpine fir, threatened by spruce beetle outbreaks and projected range reduction under warming.

Picea glauca

Picea glauca, white spruce (also Canadian spruce, Black Hills spruce), a dominant boreal conifer of Alaska and Canada. Transcontinental range, 25 m average height, pulp and lumber wood; improved seedlots grow 17% faster.

Picea mariana

Picea mariana, black spruce (bog spruce, swamp spruce), a dominant North American boreal conifer from Alaska to Newfoundland, with semiserotinous cones adapted to fire, Canada's most important pulpwood species, IUCN Least Concern.

Picea rubens

Picea rubens, red spruce (épinette rouge), a medium-sized Pinaceae conifer of eastern North America from the Canadian Maritimes to the southern Appalachians; long-lived, shade-tolerant, IUCN Least Concern, timber and musical-instrument wood.

Picea sitchensis

Picea sitchensis, Sitka spruce (coast, tideland, or yellow spruce), the world's largest spruce, a conifer native to the Pacific coast from Alaska to northern California, widely planted in Britain and Ireland for timber, with acidic-soil, hypermaritime habitat requirements.

Picris

Picris (oxtongues) is a genus of 46 accepted species of Asteraceae herbs in tribe Cichorieae, subtribe Hypochaeridinae, named by Linnaeus in 1753, native to the temperate and subtropical Old World and Australia, with P. hieracioides as type species.

Pieris

Pieris names two genera: Pieris D.Don (1834), about nine Ericaceae shrub species from Himalaya to East Asia and eastern North America, and Pieris Schrank, 1801, the Pieridae white butterflies including Pieris napi.

Pigeon pea

Pigeon pea (Cajanus cajan), also red gram or gungo pea, is a drought-resistant tropical legume shrub domesticated in India from C. cajanifolius, grown on about 6 million ha for protein-rich seeds, fodder, and soil-improving nitrogen fixation.

Pilaf

Pilaf, also called pilau or pulao, is a rice dish cooked in seasoned liquid so every grain stays separate, known across Turkey, Iran, Central Asia, and India.

Pilea

Pilea (Urticaceae) is the largest genus in the nettle family, about 614–715 species of succulent herbs across tropical America and the Old World, with explosive flowers, catapulted seeds, and the houseplant Chinese money plant.

Pilea peperomioides

Pilea peperomioides (镜面草), the Chinese money plant, is a Urticaceae perennial native to SW Sichuan and W Yunnan, China, brought to Norway in 1946 by missionary Agnar Espergen, propagated by offsets and cuttings, and known for round peltate leaves.

Pilgerodendron

Pilgerodendron, sole species Pilgerodendron uviferum (ciprés de las Guaitecas, ten), a monotypic Vulnerable Cupressaceae conifer of southern Chile and Argentina, CITES Appendix I, dioecious, slow-growing bog-forest tree with low genetic diversity.

Pilosella

Pilosella (hawkweeds) is a genus of Asteraceae, tribe Cichorieae, formerly a subgenus of Hieracium, distinguished by stolons, one-rowed pappus, and facultative aposporous apomixis controlled by LOA and LOP loci; includes the weed and medicinal plant P. officinarum.

Pilosocereus royenii

Pilosocereus royenii, Royen's tree cactus, is a spiny tree-like Caribbean cactus from Mexico and the Antilles; taxonomically disputed (synonym of P. polygonus per Kew), bee-pollinated in Puerto Rico, Least Concern, CITES Appendix II.

Pilularia

Pilularia (pillworts) is a genus of seven accepted species of heterosporous aquatic ferns in Marsileaceae, Salviniales, with thread-like bladeless leaves and spherical four-valved sporocarps; sister to Regnellidium, with Marsilea outside that clade.

Pilularia globulifera

Pilularia globulifera (pillwort, Pillenfarn) is a tiny aquatic fern of Marsileaceae, native from Europe to Kazakhstan and Ethiopia, with thread-like leaves and 3 mm round sporocarps; globally Least Concern but nationally scarce and declining in Britain.