''Parietaria'' is a genus of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family

Urticaceae The Urticaceae are a family, the nettle family, of flowering plants. The family name comes from the genus ''Urtica''. The Urticaceae include a number of well-known and useful plants, including nettles in the genus ''Urtica'', ramie (''Boehmeria ...

, native to temperate and tropical regions across the world.Flora Europaea
''Parietaria''
/ref>African Flowering Plants Database
''Parietaria'' (enter genus name in search box)
/ref>Flora of North America
''Parietaria''
/ref>Flora of China
''Parietaria''
/ref>Flora of Pakistan
''Parietaria''
/ref>Australian Plant Name Index
''Parietaria''
/ref> They are annual or

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

s growing to 20–80 cm tall, with green or pink stems. The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are alternate, simple, entire, often with a cluster of small leaves in their axils. Individual

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are

bisexual Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females. It may also be defined as the attraction to more than one gender, to people of both the same and different gender, or the attraction t ...

unisexual Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, produced in clusters of three to many together in the leaf axils. Plants have either bisexual flowers or both staminate ("male") and carpellate ("female") flowers. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

is a small dry

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...

Species

The Plant List The Plant List was a list of botanical names of species of plants created by the Royal Botanic Gardens, Kew and the Missouri Botanical Garden and launched in 2010. It was intended to be a comprehensive record of all known names of plant specie ...

accepted only 10 species:Search for "Parietaria", *'' Parietaria cretica'' L. *'' Parietaria debilis'' G.Forst. (syn. ''Parietaria micrantha'' Ledeb.) *'' Parietaria floridana'' Nutt. *'' Parietaria judaica'' L. (syn. ''Parietaria diffusa'' Mert. & W.D.J.Koch) *'' Parietaria lusitanica'' L. *'' Parietaria macrophylla'' B.L. Rob. & Greenm. *'' Parietaria mauritanica'' Durieu *'' Parietaria officinalis'' L. *'' Parietaria pensylvanica'' Muhl. ex Willd. *'' Parietaria praetermissa'' B.D. Hinton Names which The Plant List did not accept but regarded as unresolved include: *''Parietaria australis'' (Nees) Blume *''Parietaria cardiostegia'' Greuter *''Parietaria filamentosa'' Webb & Berthel. *'' Parietaria hespera'' B.D.Hinton *''Parietaria laxiflora'' Engl. *''Parietaria ruwenzoriensis'' Cortesi Other species have been moved to different genera: *''Parietaria alsinifolia'' Delile = '' Freirea alsinaefolia'' (Delile) Gaudich. Several species can be

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

s; the Mediterranean species ''P. judaica'' is widely

naturalised Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...

in the Americas, while the American ''P. pensylvanica'' is conversely naturalised in Europe.

References

{{taxonbar , from=Q163536 Urticaceae genera Taxa named by Carl Linnaeus