Plants

Plant hormone (phytohormone): roles, types, and significance Plant hormone Phytohormones are small signal molecules produced by plant cells that coordinate growth, development, stress responses and interactions with other organisms.

Plant Morphology — Study of Plant Form, Structure, and Development Plant morphology Plant morphology examines the external form and visible structures of plants, their variation, development and role in identification, classification, ecology, agriculture and evol…

Plant pathology (phytopathology) Plant pathology Plant pathology examines the causes, development, diagnosis, management, and impact of plant diseases caused by pathogens and environmental factors, with emphasis on agriculture, e…

Plant physiology: functions, processes, and applications Plant physiology Plant physiology examines the functional processes of plants — growth, energy conversion, transport, development and responses — and their relevance to ecology, agriculture and bio…

Plant propagation: methods, uses, and practical guidance Plant propagation An accessible overview of plant propagation covering sexual and asexual methods, common techniques (seeds, cuttings, grafting, tissue culture), practical tips, historical context a…

Plant sap: composition, transport, functions, and distinctions Plant sap An overview of plant sap: what it is, how xylem and phloem transport fluids, composition and mechanisms, ecological and human uses, and differences from latex and resin.

Plant Stem: Structure, Function, and Types of Above- and Below-Ground Stems Plant stem Overview of plant stems: anatomy (nodes, internodes, tissues), key functions (support, transport, storage, growth) and common above- and below-ground types such as stolons, rhizome…

Plantaginaceae — the plantain family Plantaginaceae Plantaginaceae is a cosmopolitan family of flowering plants in the order Lamiales. It includes herbaceous species and a few shrubs such as Plantago, Veronica, Penstemon and Digital…

Plantain (cooking banana): botany, uses, history and cultivation Plantain Plantain, a starchy cooking banana (genus Musa), is a tropical staple used like a vegetable. This article explains its botany, varieties, culinary uses, history and cultivation.

Plantation: large-scale specialized agriculture and its impacts Plantation Definition, typical crops, historical development, economic role, environmental and social effects, and modern trends in large-scale plantation agriculture.

Plantation of Ulster Early 17th‑century, government‑organised settlement of Ulster by mainly Scottish and English Protestant tenants to secure crown control, redistribute land and introduce new legal a…

Planthopper (Fulgoromorpha): appearance, life cycle, ecology, and importance Planthopper Planthoppers are sap-feeding insects in the infraorder Fulgoromorpha. This article summarizes their biology, distinctive features, worldwide diversity, ecological roles and relevan…

Plastid (plant and algal organelle) Plastid Plastids are self-replicating organelles in plants and algae that carry out photosynthesis, store compounds, and synthesize metabolites; they contain their own DNA (the plastome) a…

Platanaceae — the plane‑tree family (Platanus) Platanaceae Platanaceae is a small family of deciduous trees represented by the genus Platanus; known for distinctive peeling bark, spherical flower and fruit clusters, and widespread use as o…

Platanus (plane trees): description, distribution, uses and threats Platanus Platanus is a small genus of large deciduous trees—plane trees or sycamores—native to the Northern Hemisphere. Known for mottled bark and urban tolerance; used in parks, avenues an…

Platanus orientalis — the Oriental plane (chenar) Platanus orientalis A large deciduous plane tree of Eurasia, known for its spreading crown, patchy bark, cultural history and use as a shade and avenue tree from the Balkans to Kashmir.

Plum (fruit) Plum Plum, a sweet stone fruit of the genus Prunus, cultivated worldwide in many varieties. Used fresh, dried (prune), cooked, fermented, and valued for flavor, nutrition, and diverse c…

Plumbaginaceae: the leadwort family of flowering plants Plumbaginaceae Plumbaginaceae is a cosmopolitan family of herbaceous plants, shrubs and climbers, notable for thrift and sea‑lavender genera used in gardens and floristry and for many salt‑tolera…

Plumcot: the plum–apricot hybrid Plumcot Plumcot is a hybrid fruit combining plum and apricot ancestry. This article explains its origins, common varieties (including pluot and aprium), characteristics, culinary uses, and…

Poa pratensis (Kentucky bluegrass): description, distribution and uses Poa pratensis Poa pratensis, commonly Kentucky bluegrass, is a cool‑season, sod‑forming perennial grass used for lawns, pastures and sports fields. Native to Eurasia and northern Africa, it is n…

Poaceae (Gramineae): the grass family Poaceae Poaceae, or Gramineae, is the global family of true grasses—diverse, widespread, and central to ecosystems and human economies, including cereals, bamboos, turf, and forage.

Poales: the order of grasses, sedges, bromeliads and related monocots Poales Poales is a large order of monocot flowering plants that includes grasses, sedges and bromeliads. It is ecologically dominant in many habitats and economically vital for food, fibe…

Podocarpaceae: the Southern Hemisphere conifer family Podocarpaceae Podocarpaceae is a diverse family of mainly Southern Hemisphere evergreen conifers, with many genera and species, Gondwanan origins, important ecological roles and some unusual mem…

Poinsettia (Euphorbia pulcherrima): description, cultivation, and cultural significance Poinsettia Poinsettia is a tropical shrub grown for its colorful bracts. Native to Mexico and Central America, it is associated with Christmas and widely produced by growers who control flowe…

Poison ivy (Toxicodendron radicans): identification, effects, and prevention Poison ivy Poison ivy is a plant whose oil urushiol causes allergic contact dermatitis. This article covers identification, biology of the rash, distribution, prevention, first aid, and how t…

Pollen tube: formation, function, and role in plant fertilization Pollen tube A pollen tube is a cellular extension that delivers sperm from a pollen grain to the ovule. This article explains its structure, growth, role in double fertilization, differences a…

Pollination Pollination is the transfer of pollen to enable sexual reproduction in plants. This article explains mechanisms, agents, types, ecological importance, and the steps leading from po…

Polygonaceae: the knotweed and buckwheat family of flowering plants Polygonaceae Polygonaceae is a family of mainly herbaceous flowering plants—including buckwheat, sorrel, rhubarb and knotweeds—characterized by a stipular sheath (ocrea), small flowers, and a c…

Pome (accessory fruit of the Rosaceae family) Pome A pome is an accessory fruit produced by plants in the Malinae subtribe of Rosaceae; the true seeds lie in a central core and the edible flesh is formed from floral tissues. Exampl…

Pomegranate (Punica granatum): biology, cultivation, uses and cultural importance Pomegranate Overview of the pomegranate, a deciduous shrub or small tree valued for edible arils and juice. Covers botanical classification, history, cultivation, culinary uses, health aspects…

Poppy: biology, varieties, cultural significance and uses Poppy Overview of the poppy: its biology, colors and forms, history of use (culinary and medicinal), role in pollination and remembrance, and distinctions between ornamental and opium-pr…

Populus: the poplars, aspens and cottonwoods — natural history and uses Populus Populus is a northern-hemisphere genus of deciduous trees and shrubs including poplars, aspens and cottonwoods. This article summarizes their traits, ecology, uses and notable rese…

Portulacaceae (purslane family) Portulacaceae Portulacaceae is a small family of mostly succulent flowering plants, including the edible purslane and several ornamental species; known for fleshy leaves, showy flowers, and drou…

Posidoniaceae Posidoniaceae is a small family of marine flowering plants (seagrasses) in the monocot order Alismatales, dominated by the genus Posidonia. These habitat-forming plants are ecologi…

Potamogeton (pondweeds): freshwater aquatic plants Potamogeton Potamogeton, commonly called pondweed, is a widespread genus of freshwater plants. This article covers their appearance, life cycle, diversity, ecological roles, uses, and manageme…

Potato (Solanum tuberosum): botany, uses, history and storage Potato Overview of the potato: its botanical traits, major varieties, nutrition and culinary uses, origins and history, cultivation basics, storage and safety notes.

Potato blight (late blight of potato) Potato blight A destructive plant disease caused by Phytophthora infestans. Late blight devastated 19th-century potato crops and remains a major threat to potatoes and tomatoes worldwide.

Prickly pear (Opuntia): overview, biology, uses and invasive history Prickly pear Prickly pear (Opuntia) is a genus of cacti with flat pads and edible fruits. Species are used as food, fencing and ornamentals, and some became invasive; notable control efforts in…

Primula — the primroses: a genus of spring-flowering herbs Primula Primula is a genus of low-growing perennial herbs (400–500 species) in the Primulaceae family, valued for early spring flowers, wide distribution in temperate and montane regions,…

Primulaceae — the primrose family: characteristics, history, and uses Primulaceae Primulaceae, commonly called the primrose family, is a group of about 24 genera of mainly herbaceous flowering plants valued in gardens and wild habitats worldwide.

Prosopis tamarugo — tamarugo, a leguminous tree of the Atacama Pampa Prosopis tamarugo Prosopis tamarugo (tamarugo) is a drought‑adapted legume endemic to northern Chile; it stabilizes soils, provides fodder and fuel, and survives on deep saline groundwater in the Pa…

Prosthechea cochleata — cockleshell (clamshell) orchid, Belize's Black Orchid Prosthechea cochleata A tropical epiphytic orchid native to Central America, the Caribbean, northern South America and southern Florida, notable for shell-like flowers and its status as Belize's nationa…

Protea — diversity, ecology and cultural importance of the South African shrub Protea Protea is a genus of woody flowering plants in the Proteaceae, notable for large, showy flower heads, high endemism in the Cape Floristic Region, bird pollination and importance as…

Proteaceae: family of Southern Hemisphere flowering plants Proteaceae Proteaceae is a diverse family of mainly Southern Hemisphere shrubs and trees (about 80 genera, under 2,000 species), including ornamental and crop plants such as Protea, Banksia a…

Proteales — Order of eudicot flowering plants (Proteaceae, Nelumbonaceae, Platanaceae) Proteales Proteales: an order of eudicot flowering plants including Proteaceae, Nelumbonaceae and Platanaceae. Concise overview of classification, evolutionary history, morphology, ecology a…

Prunus: the genus of plums, cherries, peaches, apricots and almonds Prunus Prunus is a temperate genus of trees and shrubs in the rose family that produces stone fruits (drupes) including plums, cherries, peaches, apricots and almonds; valued for food, ti…

Prunus japonica (Korean cherry) — description, distribution, and uses Prunus japonica Prunus japonica, the Korean cherry or flowering almond, is a compact deciduous shrub grown for spring blossom and small tart fruit; native to parts of East Asia and used ornamental…

Prunus mume (Ume): the East Asian plum or Japanese apricot Prunus mume Prunus mume, known as ume, is an East Asian deciduous tree valued for fragrant winter blossoms and a tart fruit used in cuisine, drinks, preserves and cultural symbolism across Chi…