4,295 articles
Perilla
Perilla, a monotypic aromatic mint genus (Perilla frutescens) from subtropical Asia; cultivated as shiso, Korean perilla leaf, and perilla oilseed; six chemotypes, perillaldehyde culinary type, EFSA genotoxicity concern.
Perilla frutescens
Perilla frutescens (shiso, Zisu, beefsteak plant), an East Asian mint-family herb grown as culinary herb and omega-3-rich oilseed; chemotypes differ in safety, with perilla ketone toxic to livestock.
Periploca
Periploca Tourn. ex L., a genus of 17 accepted species in Apocynaceae (Periplocoideae), native from Macaronesia and the Mediterranean to tropical Africa and Asia; includes medicinal species P. sepium (Xiangjiapi) and P. forrestii (Heiguteng).
Peristome and spore discharge in bryophytes
The peristome is the ring of teeth around a moss capsule's mouth that opens and closes with humidity to release spores; liverworts and hornworts use other mechanisms.
Persea
Persea (laurel family, Lauraceae), genus of evergreen trees including the avocado Persea americana; about 112-150 species native to the Americas and Macaronesia, with Asian species often split off as Machilus; also yields medang timber.
Persicaria
Persicaria (knotweeds, smartweeds), a genus of about 100-150 species in Polygonaceae, cosmopolitan, split from Polygonum, recognized by ocrea and swollen nodes; includes weeds, ornamentals, and Asian mint.
Persicaria hydropiper
Persicaria hydropiper (water-pepper, marshpepper knotweed), Polygonaceae annual of wet ground, native temperate Eurasia, pungent from polygodial drimane sesquiterpenes; used as spice, medicine, poison; IUCN least concern.
Persicaria maculosa
Persicaria maculosa (spotted ladysthumb, redshank, lady's thumb; formerly Polygonum persicaria) is an annual Polygonaceae herb native to temperate Eurasia, a weed of spring crops with dark-blotched leaves and pink flower spikes, used as poison and medicine.
Persicaria odorata
Persicaria odorata, known as Vietnamese coriander or rau răm, is a perennial herb of the buckwheat family native to Southeast Asia, whose pungent, coriander-like leaves flavor laksa, salads, and laab.
Persimmon
The persimmon (Diospyros kaki), also called the Japanese or kaki persimmon, is a deciduous fruit tree native to China and the most cultivated persimmon in the world.
Pescatoria
Pescatoria (also spelled Pescatorea) is a genus of 21 accepted neotropical orchid species in Zygopetalinae, Orchidaceae, native from Costa Rica to Ecuador; it absorbed Bollea and is a parent of the hybrid genus × Zygosepescalum.
Pests and diseases of cultivated orchids
Pests and diseases of cultivated orchids span roughly 30 viruses, fungi, water molds, bacteria, and pests; viral infections cannot be cured, so management relies on exclusion and sanitation.
Pests and diseases of yews and plum yews
Pests and diseases of yews and plum yews describes the main Taxus problems: Phytophthora root rot from poor drainage, black vine weevil, scales, and Cryptocline needle blight.
Petal
A petal is one of the sterile, often brightly colored floral organs that form the corolla inside the sepals, attracting pollinators by color, scent, and ultraviolet patterns.
Petasites
Petasites (butterbur), Asteraceae genus of rhizomatous Northern Hemisphere perennials with huge leaves; P. hybridus studied for migraine and allergic rhinitis; contains hepatotoxic pyrrolizidine alkaloids.
Petasites hybridus
Petasites hybridus (butterbur, pestilence wort) is an Asteraceae rhizomatous geophyte native from Europe to North Iran and Algeria, studied for migraine and hay fever, but toxic unless pyrrolizidine alkaloids are removed.
Petiole (botany)
In botany, a petiole, also called a leaf stalk, is the stalk attaching a leaf blade to the stem, carrying water, nutrients, and sugars between leaf and stem.
Petrea
Petrea is a genus of woody climbers and shrubs in the verbena family, native from Florida through tropical America, known for the wisteria-like queen's wreath vine.
Petrea volubilis
Petrea volubilis (queen's wreath, purple wreath, sandpaper vine) is a twining woody vine in Verbenaceae native to tropical America, grown ornamentally for wisteria-like racemes whose persistent pale calyx lobes outlast the darker corollas.
Petunia
Petunia, garden petunia (Petunia x hybrida), South American Solanaceae genus and bedding plant; hybrid of P. axillaris and P. integrifolia, sold as F1 seed in grandiflora, multiflora, milliflora, and spreading classes, and a plant model for pollination syndrome genetics.
Petunia × atkinsiana
Petunia × atkinsiana, also called Petunia × hybrida, is the artificial hybrid garden petunia (Solanaceae) derived mainly from P. axillaris and P. integrifolia; its cultivars are grouped as grandiflora, multiflora, milliflora, and spreading types.
Peumus boldus
Peumus boldus (boldo) is a Monimiaceae tree endemic to central and southern Chile, source of boldo leaf herbal medicine and the alkaloid boldine, used traditionally for digestive disorders.
Peyote
Peyote (Lophophora williamsii) is a spineless mescaline-containing cactus of south Texas and northern Mexico, used ceremonially for over 5,000 years, sacred to the Native American Church, legally exempted for traditional Native American use, and listed as Vulnerable by the IUCN.
Phaeoceros
Phaeoceros (Prosk. 1951) is a cosmopolitan hornwort genus in Notothyladaceae, type species P. laevis, with about 34 species, one pyrenoid-bearing chloroplast per cell, no schizogenous cavities, and yellow spores.
Phalaenopsis
Phalaenopsis, moth orchids, is an orchid genus established by Blume in 1825, native from tropical Asia to NE Australia, mainly epiphytic, and the most important orchid genus in cultivation.
Phalaris canariensis
Phalaris canariensis (canary grass, alpiste), annual Poaceae grass native to the Canary Islands and Morocco, grown mainly in Saskatchewan, Canada, for birdseed; glabrous grain approved for human food in 2016, gluten-free, 22% protein.
Phalaris minor
Phalaris minor (littleseed canarygrass), a tufted annual Poaceae weed native from Macaronesia to the Himalaya, is a major wheat weed whose Indian biotypes evolved isoproturon resistance in 1991 and later resistance to six herbicide mode-of-action groups.
Phaseolus
Phaseolus is a New World legume genus (Fabaceae, tribe Phaseoleae) of about 81 species, including five domesticated beans such as common bean P. vulgaris and lima bean, with at least seven independent domestication events.
Phaseolus coccineus
Phaseolus coccineus, the runner or scarlet runner bean, is a Mesoamerican domesticated climbing legume, third-most important Phaseolus crop, grown for dry seeds and green pods, tolerating cool climates.
Phaseolus vulgaris
Phaseolus vulgaris, the common bean (fríjol, haricot), is an annual American legume domesticated independently in Mesoamerica and the Andes; grown as kidney, pinto, navy, black, and green beans, it is the world's most important direct-consumption grain legume.