{{short description|Species of plant}} {{Speciesbox |image = Lathyrus linifolius RF.jpg |image_caption = |status = LC |status_system = IUCN3.1 |status_ref=<ref name="iucn status 23 November 2021">{{cite iucn |author=Rowe, J. |author2=Sánchez, E. |author3=Maxted, N. |date=2019 |title=''Lathyrus linifolius'' |volume=2019 |article-number=e.T120074556A122201956 |doi=10.2305/IUCN.UK.2019-2.RLTS.T120074556A122201956.en |access-date=23 November 2021}}</ref> |genus = Lathyrus |species = linifolius |authority = (Reichard) Bässler |synonyms = *''Lathyrus macrorrhizus'' {{Au|Wimm.}} *''Lathyrus montanus'' {{Au|Bernh.}} *''Orobus linifolius'' {{Au|Reichard}} *''Orobus tuberosus'' {{Au|"L., ''p.p.''"}} |synonyms_ref = <ref name=TPL>{{ThePlantList | id = ild-7763 | taxon = Lathyrus linifolius | authority = (Reichard) Bassler | accessdate = 2016-08-02 }}</ref> }}

'''''Lathyrus linifolius''''' is a species of pea, commonly called '''bitter vetch''' or '''heath pea'''. The name bitter vetch is also sometimes used for ''Vicia ervilia'' and also for ''Vicia orobus''.

The tubers of ''L.&nbsp;linifolius'' were formerly used as an appetite suppressant in medieval Scotland, and this use has brought the plant to recent medical attention.

==Description== ''Lathyrus linifolius'' is a perennial plant with dark-coloured tubers up to {{Convert|3|cm|frac=4}} wide attached to the roots. The stem grows to {{convert|50|cm|abbr=on}} tall and is erect, winged<ref name="tfb2">{{Cite book |last=Francis-Baker |first=Tiffany |title=Concise Foraging Guide |date=2021 |publisher=Bloomsbury |isbn=978-1-4729-8474-6 |series=The Wildlife Trusts |location=London |page=96}}</ref> and nearly hairless. The leaves are alternate with short winged stalks and large stipules. The leaf blades are pinnate with two to four pairs of narrow lanceolate leaflets with blunt tips, entire margins and no tendrils. The inflorescence has a long stem and two to six red flowers, each {{convert|10|to|16|mm|abbr=on|frac=16}} long, turning bluer as they age. These have five sepals and five petals and are irregular. The uppermost petal is known as the "standard", the lateral two as the "wings" and the lowest two are joined to form the "keel". There are ten stamens and a single carpel. The fruit is a long reddish-brown pod containing up to ten seeds. This plant flowers in May and June.<ref name=NatureGate>{{cite web |url=https://www.luontoportti.com/suomi/en/kukkakasvit/bitter-vetch |title=Bitter vetch: ''Lathyrus linifolius'' |publisher=NatureGate |access-date=2013-12-31}}</ref>

==Distribution and habitat== ''Lathyrus linifolius'' is native to Europe and parts of Asia. Its typical habitat is rough grassy places, broad-leaved woodland, forest margins, hedgerows and banks.<ref name=NatureGate/>

==Uses== The tubers can be eaten raw but are better cooked and eaten like chestnuts.<ref name="tfb2" />

The plant may be the one eaten by Roman soldiers in the battle of Dyrrhacium in 48 BCE.<ref name="Scotsman">{{cite news |date=3 June 2006 |title=New bloom for heath pea as a slimming aid |url=http://www.scotsman.com/news/new-bloom-for-heath-pea-as-a-slimming-aid-1-1412434 |archive-url=https://web.archive.org/web/20160820064322/http://www.scotsman.com/news/new-bloom-for-heath-pea-as-a-slimming-aid-1-1412434 |archive-date=2016-08-20 |access-date=2016-08-03 |newspaper=The Scotsman |location=Edinburgh}}</ref>

The plant was formerly an ingredient of the Highland diet when food was scarce until the 18th century, when the potato became an important crop in the region. The small tubers were removed from the roots and dried. Once eaten, they prevented thirst and hunger pangs. Certain medieval herbals{{which|date=January 2021}} claimed that this effect could last for days or even weeks. It is surmised that this effect derives from the presence in them of transethanol.<ref name="Scotsman" /> Attempts are being made to cultivate the plant on a commercial scale.<ref name="Scotsman" />

==References== {{Reflist}}

==External links== *[https://web.archive.org/web/20090307045452/http://www.heathpea.co.uk/ Heath Pea site for Schools, Crofters and Farmers] *[https://www.telegraph.co.uk/gardening/3317528/Country-notebook-the-bitter-pea-thats-a-master-of-disguise.html The bitter pea that is a master of disguise]

{{Taxonbar|from=Q158866}}

linifolius Category:Flora of Europe

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