Trema (plant)

{{Short description|Genus of flowering plants belonging to the hop and hemp family}} {{other uses|Trema (disambiguation)}} {{Automatic taxobox |image = Flowers & leaves I IMG 3453.jpg |image_caption = Flowers & leaves of ''Trema orientale'' at Kolkata, West Bengal, India |taxon = Trema |authority = Lour. 1790 |subdivision_ranks = Species |subdivision = About 15 species; see text |synonyms = * ''Parasponia'' Miq. 1851 * ''Sponia'' Comm. ex Decne. 1834 }}

'''''Trema''''' is a genus of evergreen trees closely related to the hackberries (''Celtis''), occurring in subtropical and tropical regions of southern Asia, northern Australasia, Africa, South and Central America, and parts of North America.<ref>{{cite web |url=https://plants.usda.gov/java/profile?symbol=TRMI2&mapType=nativity&photoID=trmi2_001_ahp.tif |title=''Trema micrantha'' (L.) Blume Jamaican nettletree |work=The PLANTS Database |publisher=United States Department of Agriculture |access-date=2009-10-06}}</ref> They are generally small trees, reaching {{convert|10|-|20|m|ft|abbr=on}} tall.

==Taxonomy== Previously included either in the elm family, Ulmaceae, or with ''Celtis'' in the Celtidaceae, genetic analysis has shown the Celtidaceae are best placed in the hemp family, Cannabaceae.<ref name=Sytsma2002>{{Citation |last1=Sytsma |first1=Kenneth J. |last2=Morawetz |first2=Jeffery |last3=Pires |first3=J. Chris |last4=Nepokroeff |first4=Molly |last5=Conti |first5=Elena |last6=Zjhra |first6=Michelle |last7=Hall |first7=Jocelyn C. |last8=Chase |first8=Mark W. |year=2002 |title=Urticalean rosids: Circumscription, rosid ancestry, and phylogenetics based on ''rbcL'', ''trnL-F'', and ''ndhF'' sequences |journal=American Journal of Botany |volume=89 |issue=9 |pages=1531–1546 |doi=10.3732/ajb.89.9.1531 |name-list-style=amp |pmid=21665755|s2cid=207690258 |doi-access= }}</ref>

==Description== The leaves are alternate, simple, {{convert|7|-|15|cm|in|abbr=on}} long, ovate-acuminate to lanceolate with a long pointed tip, and evenly serrated margins. The fruit is a small drupe {{convert|3|-|5|mm|in|abbr=on}} in diameter.

==Species associations== ''Trema'' species are sometimes used as food plants by the larvae of hepialid moths of the genera ''Aenetus'', including ''A. splendens'', which burrow horizontally into the trunk then vertically down, and ''Endoclita'', including ''E. malabaricus''.

Some ''Trema'' species unusually able to live in symbiosis with rhizobia for nitrogen fixation as a non-legume. In this case it is customary to mention these species as a separate genus ''Parasponia''.<ref>{{cite journal |last1=Op den Camp |first1=R |last2=Streng |first2=A |last3=De Mita |first3=S |last4=Cao |first4=Q |last5=Polone |first5=E |last6=Liu |first6=W |last7=Ammiraju |first7=JS |last8=Kudrna |first8=D |last9=Wing |first9=R |last10=Untergasser |first10=A |last11=Bisseling |first11=T |last12=Geurts |first12=R |title=LysM-type mycorrhizal receptor recruited for rhizobium symbiosis in nonlegume Parasponia. |journal=Science |date=18 February 2011 |volume=331 |issue=6019 |pages=909–12 |doi=10.1126/science.1198181 |pmid=21205637}}</ref>

==Uses== ''Trema orientale'' is widely planted for land reclamation in southern Asia, valued for its tolerance of poor soils due to its ability to fix nitrogen. It is also an invasive species on some Pacific Ocean islands.<ref>{{Cite web |last1=Hanum |first1=Faridah |last2=van der Maeson |first2=L.J.G |date=1997 |title=Plant Resources of South East Asia |url=https://core.ac.uk/download/pdf/29327836.pdf |access-date=2022-11-14 |website=Core |page=25 }}</ref>

<gallery> Image:Bark I IMG 3300.jpg|Bark of ''T. orientalis'' at Kolkata, West Bengal, India File:Trema orientalis (Pigeon Wood) W IMG 2236.jpg|Flowers of ''T. orientale'' in Goa, India. File:Trema orientalis (Pigeon Wood) W2 IMG 2237.jpg|Leaves of ''T. orientale'' in Goa, India. File:Trema orientalis (Pigeon Wood) W2 IMG 2236.jpg|Flowers of ''T. orientale'' in Goa, India. Image:Branches I IMG 3304.jpg|Branches of ''T. orientale'' at Kolkata, West Bengal, India </gallery>

==Species== ''Trema'' comprises the following species:<ref name=POWO>{{cite web |url = https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:41025-1 | author=Govaerts R | website = Plants of the World Online | title = ''Trema'' Lour. | publisher=Board of Trustees of the Royal Botanic Gardens, Kew | accessdate = 22 March 2023}}</ref> {{div col|colwidth=350px}} *''Trema andersonii'' (Planch.) Byng & Christenh. *''Trema angustifolium'' (Planch.) Blume *''Trema cannabina'' Lour. – '''type species''' - Lesser trema (many synonyms including ''T. vieillardii'' (Planch.) Schltr.) *''Trema cubense'' Urb. *''Trema discolor'' (Brongniart) Blume *''Trema domingense'' Urb. *''Trema eurhynchum'' (Miq.) Byng & Christenh. *''Trema humbertii'' J.-F.Leroy *''Trema lamarckianum'' (Roem. & Schult.) Blume – West Indian trema, Lamarck's trema *''Trema levigatum'' Hand.-Mazz. *''Trema melastomatifolium'' (J.J.Sm.) Byng & Christenh. *''Trema micranthum'' (L.) Blume – Jamaican nettle tree *''Trema nitidum'' C.J. Chen *''Trema orientale'' (L.) Blume – Pigeon wood (synonym ''T. affinis'' (Planch.) Blume, ''T. orientalis'') *''Trema parviflorum'' (Miq.) Byng & Christenh. *''Trema politoria'' (Planch.) Blume *''Trema simulans'' (Merr. & L.M.Perry) Byng & Christenh. *''Trema tomentosum'' (Roxb.) H.Hara – Poison peach ** var. ''tomentosum'' (Roxb.) H.Hara ** var. ''viride'' (Planch.) Hewson – eastern Australia (synonym ''T. asperum'' (Brongn.) Blume) {{div col end}}

===Species names with uncertain taxonomic status=== The status of the following species is unresolved:<ref name="PlantList">{{cite web | url = http://www.theplantlist.org/1.1/browse/A/Cannabaceae/Trema/ | title = The Plant List entry for ''Trema'' | date = September 2013 | website = The Plant List, v.1.1 | publisher = Royal Botanic Gardens, Kew and the Missouri Botanical Garden | accessdate = 14 December 2020}}</ref> {{div col|colwidth=18 em}} * ''Trema acuminatissima'' Boerl. * ''Trema argentea'' Blume * ''Trema blancoi'' Blume * ''Trema bracteolata'' Blume * ''Trema burmanni'' Blume * ''Trema carinata'' Blume * ''Trema crassifolia'' Liebm. * ''Trema glabrescens'' Blume * ''Trema glomerata'' Blume * ''Trema griffithii'' Blume * ''Trema guinensis'' Priemer * ''Trema imbricata'' Blume * ''Trema lancifolia'' Ridl. * ''Trema malaccensis'' Gand. * ''Trema morifolia'' Blume * ''Trema pallida'' Blume * ''Trema philippinensis'' Elmer * ''Trema pubigera'' Blume * ''Trema rigida'' Blume * ''Trema rugosa'' Blume * ''Trema scaberrima'' Blume * ''Trema sieberi'' Blume * ''Trema strigilosa'' Lundell * ''Trema strigosa'' Blume * ''Trema viridis'' Blume * ''Trema vulcanica'' Merr. {{div col end}}

==References== {{Reflist|2}}

==External links== *{{Commons category inline}} *{{Wikispecies inline|Trema|''Trema''}} *[http://www.hear.org/pier/species/trema_orientalis.htm Pacific Island Ecosystems at Risk (PIER) page on ''Trema orientalis'' (with photos)]

Category:Trema (plant) Category:Rosales genera Category:Taxa named by João de Loureiro