Urticaceae

Nettle family
File:Urtica-dioica(Blueten).jpg
Urtica dioica (stinging nettle)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Rosales
Family:	Urticaceae Juss., 1789
Synonyms
Cecropiaceae C. C. Berg

Urticaceae /ɜːrtᵻˈkeɪsiː/, the nettle family, is a family of flowering plants. The family name comes from the genus Urtica. Urticaceae includes a number of well-known and useful plants, including the nettles, ramie (Boehmeria nivea), māmaki (Pipturus albidus), and ajlai (Debregeasia saeneb).

The family includes about 2600 species, grouped into 54 to 79 genera according to the database of the Royal Botanic Gardens, Kew. The largest genera are Pilea (500 to 715 species), Elatostema (300 species), Urtica (80 species), and Cecropia (75 species).

Urticaceae can be found worldwide, apart from the polar regions.

Description

Urticaceae can be shrubs (e.g. Pilea), lianas, herbs (e.g. Urtica, Parietaria), or, rarely, trees (Dendrocnide, Cecropia). Their leaves are usually entire and bear stipules. Urticating (stinging) hairs are often present. Urticaceae have usually unisexual flowers and can be both monoecious or dioecious. They are wind-pollinated. Most disperse their pollen when the stamens are mature and their filaments straighten explosively, a peculiar and conspicuously specialised mechanism.

Taxonomy

Male and female flower of Urtica

The APG II system puts the Urticaceae in the order Rosales, while older systems consider them part of the Urticales, along with Ulmaceae, Moraceae, and Cannabaceae. APG still considers "old" Urticales a monophyletic group, but does not recognise it as an order on its own.

Genera (partial list)

Aboriella Achudemia Archiboehmeria Astrothalamus Australina Boehmeria Cecropia Chamabainia Coussapoa Cypholophus Debregeasia Dendrocnide Didymodoxa Discocnide Droguetia Elatostema

Forsskaolea Gesnouinia Gibbsia Girardinia Laportea Lecanthus Leucosyke Maoutia Meniscogyne Metatrophis Myriocarpa Nanocnide Neodistemon Neraudia Nothocnide Obetia Oreocnide

Parietaria Pellionia Petelotiella Phenax Pilea Pipturus Poikilospermum Pouzolzia Procris Rousselia Sarcochlamys Sarcopilea Soleirolia Touchardia Urera Urtica - nettle

Diseases

The Urticaceae are subject to many bacterial, viral, fungal, and nematode parasite diseases. Among them are:

• Bacterial leaf spot, caused by Xanthomonas campestris which affects Pellionia, Pilea and other genera
• Anthracnose, a fungal disease caused by Colletotrichum capsici which affects the Pilea
• Myrothecium leaf spot, a fungal disease caused by Myrothecium roridum which affects plants throughout the Urticaceae, as well as other angiosperms
• Phytophthora blight, a water mold disease caused by Phytophthora nicotianae which affects Pilea
• Southern blight, a fungal disease caused by Sclerotium rolfsii which affects both Pellionia and Pilea

Image gallery

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  Pilea cadierei

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  Pilea pumila

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  Dendrocnide sp.

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  Elatostema umbellatum

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  Urtica dioica

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  Boehmeria nivea

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  Parietaria judaica, flowers

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  Urtica dioica, stinging hairs

External links

• continuously updated.