Cyclospermum leptophyllum

{{Short description|Species of flowering plant}}

{{Speciesbox

|image = Starr_010520-0107_Ciclospermum_leptophyllum.jpg

|genus = Cyclospermum

|species = leptophyllum

|authority = (Pers.) Sprague ex Britton & P. Wils.

|synonyms = Apium leptophyllum
Apium tenuifolium
Cyclospermum ammi

}}

Cyclospermum leptophyllum (also, Ciclospermum l.) is a species of plant in the family Apiaceae known by the common names marsh parsley,{{PLANTS|id=CYLE7|taxon=Cyclospermum leptophyllum|accessdate=17 January 2016}} slender celery{{BSBI 2007 |accessdate=2014-10-17 }} and fir-leaved celery; one source also mentions the name of wild cherry,{{Cite web |url=http://www.ipmcenters.org/cropprofiles/docs/FLCelery.html |title=Crop Profiles |access-date=4 March 2009 |archive-url=https://web.archive.org/web/20100809071738/http://www.ipmcenters.org/cropprofiles/docs/FLCelery.html |archive-date=9 August 2010 |url-status=dead }} although this may be a misspelling of "wild celery". This is a plant found worldwide at warm temperate to tropical latitudes and is considered a noxious weed in many areas. It is a taprooted branching herb reaching just over half a meter in height at maximum. It has threadlike green leaves a few centimeters long and small umbels of spherical flowers. Host plant for Eastern Black Swallowtail butterflies.

The 1889 book 'The Useful Native Plants of Australia’ records that a common name included "Wild Parsley" and that "It is worthy of note that this plant (in common with others of the genus) is sometimes acrid and injurious when grown in damp soils. It is, doubtless, capable of much improvement by careful cultivation. This plant is not endemic to Australia."{{cite book | author=J. H. Maiden | year=1889 | title=The useful native plants of Australia : Including Tasmania | publisher= Turner and Henderson, Sydney | url=https://primo-slnsw.hosted.exlibrisgroup.com/primo-explore/fulldisplay?docid=SLNSW_ALMA21105097830002626&context=L&vid=SLNSW&search_scope=EEA&tab=default_tab&lang=en_US}}