Urticaceae Explained

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 nivea), māmaki (Pipturus albidus), and ajlai (Debregeasia saeneb).

The family includes about 2,625 species, grouped into 53 genera according to the database of the Royal Botanic Gardens, Kew and Christenhusz and Byng (2016).[1] The largest genera are Pilea (500 to 715 species), Elatostema (300 species), Urtica (80 species), and Cecropia (75 species). Cecropia contains many myrmecophytes.[2]

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

Description

Urticaceae species 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. They 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.

While the stings delivered by Urticaceae species are often unpleasant, they seldom pose any direct threat to health, and deaths directly attributed to stinging are exceedingly rare; species known to cause human fatalities include Dendrocnide cordata[3] [4] and Urtica ferox.[5]

Taxonomy

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.

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.[6] A Colombian fossil flora of the Maastrichtian stage has yielded leaves that resemble leaves of the tribe Ceropieae.[7] 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.[8]

Phylogeny

Modern molecular phylogenetics suggest the following relationships[9] [10] (see also [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]):

Tribes and genera

Diseases

The Urticaceae are subject to many bacterial, viral, fungal, and nematode parasitic diseases. Among them are:[22]

Further reading

External links

Notes and References

  1. Christenhusz, M. J. M., and Byng, J. W. . 2016 . The number of known plants species in the world and its annual increase . . 261 . 201–217 . 10.11646/phytotaxa.261.3.1 . 3 . free .
  2. Chomicki G, Renner SS. . 2015 . Phylogenetics and molecular clocks reveal the repeated evolution of ant-plants after the late Miocene in Africa and the early Miocene in Australasia and the Neotropics . . 207 . 2 . 411–424 . 10.1111/nph.13271 . 25616013. free .
  3. Web site: Hurley . Marina . Selective Stingers . ECOS . . October–December 2000.
  4. MacFarlane . W.V. . The Stinging Properties of Laportea . Economic Botany . 1963 . 17 . 4 . 303–311 . 10.1007/BF02860137 . 4252456 . 546456 .
  5. http://www.teara.govt.nz/TheBush/NativePlantsAndFungi/PoisonousPlantsAndFungi/1/en Poisonous native plants
  6. Book: Early Flowers and Angiosperm Evolution . . Peter R. Crane . Kaj Raunsgaard Pedersen . Cambridge University Press . 18 Aug 2011 . 978-0-521-59283-3.
  7. Treiber . E. L. . Gaglioti . A. L. . Romaniuc-Neto . S. . Madriñán . S. . Weiblen . G. D. . 2016 . Phylogeny of the Cecropieae (Urticaceae) and the evolution of an ant-plant mutualism . Systematic Botany . 41 . 1 . 56–66 . 10.1600/036364416X690633. 28743975 .
  8. DeVore . M. L. . Nyandwi . A. . Eckardt . W. . Bizuru . E. . Mujawamariya . M. . Pigg . K. B. . 2020 . Urticaceae leaves with stinging trichomes were already present in latest early Eocene Okanogan Highlands, British Columbia, Canada . American Journal of Botany . 107 . 10 . 1449–1456 . 10.1002/ajb2.1548 . 33091153 . 225050834 . free .
  9. Wu Z-Y, Monro AK, Milne RI, Wang H, Liu J, Li D-Z. . 2013 . Molecular phylogeny of the nettle family (Urticaceae) inferred from multiple loci of three genomes and extensive generic sampling . . 69 . 3 . 814–827 . 10.1016/j.ympev.2013.06.022 . 23850510.
  10. Wu Z-Y, Milne RI, Chen C-J, Liu J, Wang H, Li D-Z. . 2015 . Ancestral state reconstruction reveals rampant homoplasy of diagnostic morphological characters in Urticaceae, conflicting with current classification schemes . . 10 . 11 . e0141821 . 10.1371/journal.pone.0141821 . 26529598 . 4631448 . 2015PLoSO..1041821W . free .
  11. Sytsma KJ, Morawetz J, Pires JC, Morden CW. . 2000 . Phylogeny of the Urticales based on three molecular data sets, with emphasis on relationships within Urticaceae . . 87 . 6 . 162 .
  12. Sytsma KJ, Morawetz J, Pires C, Nepokroeff M, Conti E, Zjhra M, Hall JC, Chase MW. . 2002 . Urticalean rosids: Circumscription, rosid ancestry, and phylogenetics based on rbcL, trnL–F, and ndhF sequences . . 89 . 9 . 1531–1546 . 10.3732/ajb.89.9.1531 . 21665755. free .
  13. Hadiah JT, Quinn CJ, Conn BJ. . 2003 . Phylogeny of Elatostema (Urticaceae) using chloroplast DNA data . . 10 . 1 . 235–246 . 10.7751/telopea20035618. free .
  14. Datwyler SL, Weiblen G. . 2004 . On the origin of the fig: Phylogenetic relationships of Moraceae from ndhF sequences . . 91 . 5 . 767–777 . 10.3732/ajb.91.5.767 . 21653431. free .
  15. Zerega NJC, Clement WL, Datwyler SL, Weiblen GD. . 2005 . Biogeography and divergence times in the mulberry family (Moraceae) . . 37 . 2 . 402–416 . 10.1016/j.ympev.2005.07.004 . 16112884. 10.1.1.418.1442 .
  16. Monro AK. . 2006 . The revision of species-rich genera: A phylogenetic framework for the strategic revision of Pilea (Urticaceae) based on cpDNA, nrDNA, and morphology . . 93 . 3 . 426–441 . 10.3732/ajb.93.3.426 . 21646202. free .
  17. Hadiah JT, Conn BJ, Quinn CJ . 2008 . Infra-familial phylogeny of Urticaceae, using chloroplast sequence data . . 21 . 5 . 375–385 . 10.1071/SB08041.
  18. Conn BJ, Hadiah JT . 2009 . Nomenclature of tribes within the Urticaceae . . 64 . 2 . 349–352 . 10.1007/s12225-009-9108-4 . 20649663. 10761027 .
  19. Kim C, Deng T, Chase M, Zhang D-G, Nie Z-L, Sun H. . 2015 . Generic phylogeny and character evolution in Urticeae (Urticaceae) inferred from nuclear and plastid DNA regions . . 64 . 1 . 65–78 . 10.12705/641.20.
  20. Treiber EL, Gaglioti EL, Romaniuc-Neto S, Madriñán S, Weiblen GD. . 2016 . Phylogeny of the Cecropieae (Urticaceae) and the evolution of an ant–plant mutualism . . 41 . 1 . 56–66 . 10.1600/036364416X690633 . 28743975 .
  21. Deng Tao . Kim C . Zhang D-G . Zhang J-W . Li Z-M . Nie Z-L . Sun H. . 2013 . Zhengyia shennongensis: A new bulbiliferous genus and species of the nettle family (Urticaceae) from central China exhibiting parallel evolution of the bulbil trait . . 62 . 1 . 89–99 . 24389315. 10.1002/tax.621008 .
  22. Web site: Common Names of Plant Diseases: Diseases of Foliage Plants (House Plants): Urticaceae. 26 March 1993. The American Phytopathological Society . https://web.archive.org/web/20111130101357/http://www.apsnet.org/publications/commonnames/Pages/FoliagePlants.aspx. 30 November 2011. live.
  23. Chase, A. R. . 1983. Influence of host plant and isolate source on Myrothecium leaf spot of foliage plants. Plant Disease. 67. 6. 668–671. 10.1094/PD-67-668.
  24. Nguyen, Thu Ha, Mathur, S. B., & Neergaard, Paul. 1973. Seed-borne species of Myrothecium and their pathogenic potential. . 61. 2. 347–354, IN14–IN16. 10.1016/S0007-1536(73)80156-1.

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