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

The family includes about 2,625 species, grouped into 53 genera. The largest genera are Pilea (500 to 715 species), Elatostema (300 species), Urtica (80 species), and Cecropia (75 species). Cecropia contains many myrmecophytes.

Urticaceae species can be found worldwide, but most species are found in tropical ecosystems, especially tropical Asia.

Description

Urticaceae species can be herbs (e.g. Urtica, Parietaria), shrubs(e.g. Pilea), hemi-epiphytes, or, rarely, trees (Dendrocnide, Cecropia). Their leaves are usually entire and bear stipules.

Urticating hairs are often present. These urticating trichomes are an herbivory defense against primarily mammals, but also defend against invertebrate herbivory as well. Pistillate flowers have superior pseudomonomerous ovaries extending to one style. This family has a gynoecium with two carpels, and a perianth of four to five. Plants are then wind-pollinated. Fruits are achenes.thumb|Male and female flower of UrticaAdditional characteristics represented by members in the family are leaves with cystolith or silicone accumulation. and Urtica ferox.

thumb|[[Urtica angustifolia, East-Asian Nettle]]

Uses

Many members of Urticaceae are cultivated and foraged worldwide for various uses, including food, medicines, and to create tools. Some notable species include:

  • Pouzolzia mixta (soap nettle), is used as a culinary herb, made into rope, and is a source of traditional medicine in several southern African countries.
  • Urtica angustifolia, which grows throughout eastern Asia, is an important traditional Chinese medicine plant.
  • Cecropia obtusa, Laportea aestuans, and Urera baccifera are all species used as anti-inflammatory and diabetes medicine in Brazil.

Diseases

The Urticaceae are subject to many bacterial, viral, fungal, and nematode parasitic 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 Pilea.
  • Phytophthora blight, a water mold disease caused by Phytophthora nicotianae which affects Pilea
  • Southern blight, a fungal disease caused by Athelia rolfsii which affects both Pellionia and Pilea

Fossil record

The fossil record of Urticaceae is scattered and mostly based on dispersed fruits. Twelve species based on fossil achenes are known from the Late Cretaceous of Central Europe. Most were assigned to the extant genera Boehmeria (three species), Debregeasia (one species) and Pouzolzia (three species), while three species were assigned to the extinct genus Urticoidea.

A Colombian fossil flora of the Maastrichtian stage has yielded leaves that resemble leaves of the tribe Ceropieae.

In the Cenozoic fossil leaves from the Ypresian Allenby Formation preserve distinct trichomes, and have been attributed to the Tribe Urticeae in the fossil record. The leaves had originally been identified as Rubus by earlier workers on the Eocene Okanagan Highlands, but Devore et al (2020) interpreted the preserved hairs along the stem and major veins as stinging trichomes, rather than simple hairs or thorns.

Taxonomy

Classification

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. Urticaceae is a monophyletic group.

Phylogeny

Modern molecular phylogenetics suggest the following relationships (see also ):

Tribes and genera

  • Boehmerieae <small>Gaudich. 1830</small>
  • Archiboehmeria <small>C.J. Chen 1980</small> (1 sp.)
  • Astrothalamus <small>C.B. Rob. 1911</small> (1 sp.)
  • Boehmeria <small>Jacq. 1760</small> (80 spp.)
  • Chamabainia <small>Wight 1853</small> (1–2 spp.)
  • Cypholophus <small>Wedd. 1854</small> (15 spp.)
  • Debregeasia <small>Gaudich. 1844</small> (4 spp.)
  • Gibbsia <small>Rendle 1917</small> (2 spp.)
  • Gonostegia <small>Turcz. 1846</small> (5 spp.)
  • Hemistylus <small>Benth. 1843</small> (4 spp.)
  • Neodistemon <small>Babu & A. N. Henry 1970</small> (1 sp.)
  • Neraudia <small>Gaudich. 1830</small> (5 spp.)
  • Nothocnide <small>Blume 1856</small> (4 spp.)
  • Oreocnide <small>Miq. 1851</small> (15 spp.)
  • Phenax <small>Wedd. 1854</small> (12 spp.)

<!-- Piptuirus is a misspelling of Pipturus. -->

  • Pipturus <small>Wedd. 1854</small> (30 spp.)
  • Pouzolzia <small>Gaudich. 1826 [1830]</small> (70 spp.)
  • Rousselia <small>Gaudich. 1826 [1830]</small> (3 spp.)
  • Sarcochlamys <small>Gaudich. 1844</small> (1 sp.)
  • Cecropieae <small>Gaudich. 1830</small>
  • Cecropia <small>Loefl. 1758</small> (70–80 spp.)
  • Coussapoa <small>Aubl. 1775</small> (>50 spp.)
  • Leucosyke <small>Zoll. & Moritzi 1845</small> (35 spp.)<!-- Micronesica40:169. -->
  • Maoutia <small>Wedd. 1854</small> (15 spp.)
  • Musanga <small>R. Br. in Tuckey 1818</small> (2 spp.)
  • Myrianthus <small>P. Beauv. 1804 [1805]</small> (7 spp.)
  • Pourouma <small>Aubl. 1775</small> (>50 spp.)
  • Elatostemateae <small>Gaudich. 1830</small> <!-- =Lecantheae Wedd. 1854; =Procrideae Wedd. 1856-->
  • Aboriella <small>Bennet</small> (1 sp.) (synonym of Achudemia)<!--in PoWO-->
  • Achudemia <small>Blume 1856</small> <!-- Achudemia is a synonym of Pilea; not in PoWO -->

<!-- Dubrueilia Gaudich. 1826 [1830] is a synonym of Pilea. -->

  • Elatostema <small>J.R. Forst. & G. Forst. 1775</small> (300 spp.)<!-- Micronesica40:169. -->
  • Gyrotaenia <small>Griseb. 1861</small> (4 spp.)

<!-- Langeveldia Gaudich. 1830 is a synonym of Procris. -->

  • Lecanthus <small>Wedd. 1854</small> (4 sp.) (syn. Meniscogyne <small>Gagnep. 1928</small>)
  • Myriocarpa <small>Benth. 1844 [1846]</small> (18 spp.)
  • Pellionia <small>Gaudich. 1826</small> (60 spp.)<!-- Pellionia is a synonym of Procris. -->
  • Petelotiella <small>Gagnep. in Lecomte 1929</small> (1 spp.)
  • Pilea <small>Lindl. 1821</small> (606 spp.) (syn. Sarcopilea <small>Urb. 1912</small>)
  • Procris <small>Comm. ex Juss. 1789</small> (24 spp.)

<!-- Sciophila Gaudich. 1830 is a synonym of Procris. -->

  • Forsskaoleeae <small>Gaudich. 1830</small>
  • Australina <small>Gaudich. 1830</small> (2 spp.)
  • Didymodoxa <small>E. Mey. ex Wedd. 1857</small> (2 spp.)
  • Droguetia <small>Gaudich. 1830</small> (7 spp.)
  • Forsskaolea <small>L. 1764</small> (6 spp.)
  • Parietarieae <small>Gaudich. 1830</small>

<!-- Freirea is a synonym of Parietaria. -->

  • Gesnouinia <small>Gaudich. 1830</small> (2 spp.)
  • Parietaria <small>L. 1753</small> (20 spp.)
  • Soleirolia <small>Gaudich. 1830</small> (1 sp.)

<!-- Thaumuria is a synonym of Parietaria. -->

  • Urticeae <small>Lamarck & DC. 1806</small> <!-- =Urereae Gaudich. 1830 -->
  • Dendrocnide <small>Miq. 1851</small> (27 spp.)
  • Discocnide <small>Chew 1965</small> (1 sp.)

<!-- Fleurya Gaudich. 1826 is a synonym of Laportea. -->

  • Girardinia <small>Gaudich. 1830</small> (2 spp.)
  • Hesperocnide <small>Torr. 1857</small> (2 spp.)
  • Laportea <small>Gaudich. 1826 [1830]</small> (21 spp.)
  • Nanocnide <small>Blume 1856</small> (2 spp.)
  • Obetia <small>Gaudich. 1844</small> (7 spp.)
  • Poikilospermum <small>Zipp. ex Miq. 1864</small> (20 spp.)
  • Touchardia <small>Gaudich. 1847</small> (1–2 spp.)
  • Urera <small>Gaudich. 1826 [1830]</small> (35 spp.)
  • Urtica <small>L. 1753</small>—nettle (80 spp.)
  • Zhengyia <small>T.Deng, D.G.Zhang & H.Sun 2013</small> (1 sp.)
  • Incertae sedis
  • Capsulea (1 sp.)
  • Elatostematoides (25 sp.)
  • Metapilea (1 sp.)
  • Metatrophis <small>F.Br. 1935</small> (1 sp.)
  • Parsana <small>Parsa & Maleki 1952</small> (1 sp.)
  • Scepocarpus (14 sp.)

<gallery>

Image:PileaCadierei.jpg|Pilea cadierei

Image:Pilea pumila2.JPG|Pilea pumila

Image:Poisonivy1.jpg|Dendrocnide sp.

Image:Elatostema umbellatum 2006.04.19 06.17.14-p4190208.jpg|Elatostema umbellatum

Image:Brennnessel 1.JPG|Urtica dioica

Image:Boehmeria nivea 1.jpg|Boehmeria nivea

Image:Parietaria judaica 000.jpg|Parietaria judaica flowers

Image:Nettle.jpg|Urtica dioica stinging hairs

File:咬人狗 Dendrocnide meyeniana 20221020185903 03.jpg|Leaves of Dendrocnide meyeniana

File:蕁麻(咬人貓) Urtica thunbergiana 20220406201651.jpg|The dotted bumps on the leaves of Urtica thunbergiana

</gallery>

References

Further reading

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