Cerastium diffusum

{{short description|Species of flowering plant in the pink family Caryophyllaceae}}

{{Speciesbox

|image = Cerastium diffusum 2.jpg

|genus = Cerastium

|species = diffusum

|authority = Pers.

|synonyms = *Cerastium atrovirens {{au|Bab.}}

• Cerastium tetrandrum {{au|Curtis}}

}}

Cerastium diffusum, the fourstamen chickweed{{PLANTS|id=CEDI7|taxon=Cerastium diffusum|accessdate=18 June 2016}} or sea mouse-ear,{{BSBI 2007 |accessdate=18 June 2016 |df=dmy-all}} is a species of flowering plant in the pink and carnation family Caryophyllaceae. It is an annual herb, up to 30 cm.high, occurring in western Europe and northern Africa. It is mainly found in coastal areas of Algeria, the Baleares, Belgium, Corsica, Denmark, France, the Faroe Islands, Germany, Great Britain, Ireland, Italy, Libya, Morocco, Netherlands, Norway, Portugal, Sardinia, Sicily, Spain and Sweden.{{cite web |title=Cerastium diffusum Pers. {{!}} Plants of the World Online {{!}} Kew Science |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:152210-1 |website=Plants of the World Online |access-date=15 April 2022 |language=en}} The flowers have 4, (or rarely 5) petals, 4 or 5 stamens appearing between March and May. The petals are much shorter than the sepals. The leaves are opposite, (sessile) without petioles and the sepals and bracts are all green, without pale margins. The fruit petioles are upright and diffuse at maturity.{{cite book|last=Stace|first=C. A.|authorlink = Stace, C. A.|year=2019|title=New Flora of the British Isles|edition=Fourth|publisher=C & M Floristics|location = Middlewood Green, Suffolk, U.K.| isbn=978-1-5272-2630-2}}{{rp|490}}{{cite book|last1=Blamey|first1=M.|last2=Fitter|first2=R.|last3=Fitter|first3=A|year=2003|title=Wild flowers of Britain and Ireland: The Complete Guide to the British and Irish Flora.|publisher=A & C Black|location=London|isbn=978-1408179505}}{{rp|52}}

There are 2 known Infraspecifics;

• Cerastium diffusum subsp. diffusum
• Cerastium diffusum subsp. gussonei {{small|(Tod. ex Lojac.) P.D.Sell & Whitehead}}

It was first published in Synopsis plantarum 1 on page 520 in 1805.