Lactuca virosa

Lactuca virosa

Wild lettuce or Poison lettuce, or called with other names (Lactuca virosa L., 1753) is a herbaceous species belonging to the Asteraceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Magnoliophyta division,
Class Magnoliopsida,
Subclass Asteridae,
Asterales Order,
Asteraceae family,
Subfamily Cichorioideae,
Tribe Cichorieae,
Genus Lactuca,
L. virosa species.
They are synonymous terms:
– Hieracium virosum (L.) E.H.L.Krause;
– Lactuca agrestis Bubani;
– Lactuca ambigua Schrad.;
– Lactuca cornigera Pau & Font Quer;
– Lactuca flavida Jord.;
– Lactuca lactucarii (Lamotte) Lamotte;
– Lactuca livida Boiss. & Reut.;
– Lactuca patersoniae Menezes;
– Lactuca patersonii Menezes;
– Lactuca romana Garsault;
– Lactuca scariola subsp. virosa (L.) Bonnier & Layens;
– Lactuca scariola subsp. virosa (L.) Rouy;
– Lactuca scariola var. altissima Lecoq & Lamotte;
– Lactuca scariola var. flavida (Jord.) Gren. & Godr.;
– Lactuca scariola var. lactucarii (Lamotte) Rouy;
– Lactuca schimperi Jord.;
– Lactuca serratifolia Sennen;
– Lactuca sinuata Forssk.;
– Lactuca virosa f. lactucarii (Lamotte) P.D.Sell;
– Lactuca virosa f. lactucarii Lamotte;
– Lactuca virosa subsp. cornigera (Pau & Font Quer) Emb. & Maire;
– Lactuca virosa subsp. livida (Boiss. & Reut.) Ladero & A.Velasco;
– Lactuca virosa var. flavida (Jord.) Cariot & St.-Lag., 1889;
– Lactuca virosa var. virosa;
– Wiestia virosa (L.) Sch.Bip..
Within this species the following subspecies are recognised:
– Lactuca virosa subsp. virosa L.;
– Lactuca virosa subsp. cornigera;
– Lactuca virosa var. lactucarii..

Etymology –
The term Lactuca comes from the Latin lac, láctis latte: due to the abundant white latex present in the plants of this genus.
The specific epithet virosa comes from viscous mucilage viscous humor, and in a pejorative sense poison, but also stench, stench, as well as bitter or acrid taste: poisonous; smelly, fetid; of unpleasant taste.

Geographic Distribution and Habitat –
Lactuca virosa is an annual plant with a Mediterranean-Turanic distribution and is present in southern and western Europe: from Great Britain (but absent in Ireland) to Poland, from the south to Portugal, Spain and Greece; North Africa – Morocco, Algeria.
In Italy this species is rare and is found more or less throughout the territory (rarer in the North-East). Outside Italy, still in the Alps, this species is found in France, Switzerland and Austria. On the other reliefs connected to the Alps it is present in the Black Forest, the Jura Massif, the Central Massif, the Pyrenees and the Carpathians. In the rest of Europe and in the Mediterranean area it is found, as mentioned, in the western area.
It is also found in the Punjab region of Pakistan, India and Australia, where it grows in the wild.
Outside this range it has been documented as introduced to California, Alabama, Iowa and Washington, DC, and grows wild in other parts of the North American continent.
Its preferred habitat is uncultivated areas, old walls and along the streets. It prefers loose soil, screes, road embankments; it is the typical plant that borders ditches and paths, especially in the mountains, and is also present in woodland clearings. The preferred substrate is calcareous but also siliceous with neutral pH, high nutritional values of the soil which must be arid.
The altitudinal distribution is varied but can be found up to 1,100 m a.s.l. and beyond depending on the latitude.

Description –
Lactuca virosa is a biennial plant up to 1.80 – 2 meters tall, with a poppy-like odor.
It has a white or reddish stem with quills.
The basal rosette can have a diameter of up to 60 cm; the leaves are blue-green, with quilled margins and underside; the sessile upper leaves are often deeply lobed; all the leaves embrace the stem and have spines on the underside.
The numerous narrow flower heads are arranged in panicles; each flower head is enclosed by overlapping blue-green bracts.
The flowering period is between June and September.
The fruit is a 7-8 mm cypsela with an obovate achene body (4)4,2-4,8(5,2) x (1)1,3-1,6(1,7) mm, more broad in its middle, with broad margins and hairs mostly near the beak; dark brown with 6-7 ribs and a 2.4-4 mm beak. Pappus 5-6.5 mm, white.

Cultivation –
Lactuca virosa is a plant that is harvested from the wild for local use as food and medicine.
Even if the term virosa suggests poisonousness, cases of poisoning by this plant have been recorded only very rarely, however it must be used with great caution; among other things, the plant is very bitter.
The plant can be cultivated and prefers a sandy or loose substrate and a sunny position.
This plant is cultivated as a medicinal plant in many areas of Europe.
Propagation is by seed and this is to be sown in spring or autumn in situ, taking care to barely cover the seed. Germination is usually quite fast.

Customs and Traditions –
Lactuca virosa is a plant known for its psychotropic (specifically hypnotic or sedative) effects which have often been described as opium-like. The hypnotic and sedative effects are also known in other species of Lactuca, even if in normal food lettuces these effects are not very perceptible. The effects of ingesting L. virosa are mildly similar to those of opium, even though no opiates are present in the plant.
In the traditional Western pharmacopoeia, an extract from the secretion of the plant is used, practiced in analogy to opium, called lactucarium. The plant has been used as an anesthetic and hypnotic, but also as a narcotic substance.
At present, also due to cultural irrelevance in some countries (such as Italy) cultivation and possession are neither prohibited nor regulated.
Oils and extracts can be obtained from L. virosa.
Its use as a galactogen is not proven.
The plant contains flavonoids, which have antioxidant properties. It also contains coumarins and methylphenylalanine. Two chemical substances responsible for the sedative and sleeping properties of L. virosa have been isolated; lactucopicrin and lactucin.
Lactuca virosa was used in the 1800s by physicians as a mild narcotic when opium was not available. In the United States, the plant experienced a resurgence in popularity in the 1970s for its psychotropic activity, while elsewhere it is largely ignored.
The plant is used both in the food and medicinal fields.
In the food field, the tender leaves are used raw or cooked, however caution is advised, due to some toxic effects.
From the seeds an oil with a delicate flavor is obtained, used in the kitchen.
In the medicinal field, as mentioned, the whole plant is rich in a milky sap that flows free from any wounds. This hardens and dries in contact with the air.
The lactucarium contained in the lymph has anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties.
Lactucarium has the effects of a weak opium, but without its tendency to cause digestive upset, nor is it addictive.
It is taken internally in the treatment of insomnia, anxiety, neurosis, hyperactivity in children, dry cough, whooping cough, rheumatic pains, etc.
Concentrations of lactucarium are low in young plants and more concentrated as the plant enters flower.
This species is probably the richest in lactucarium concentration.
The plant also contains hyoscyamine, a potent parasympathetic nervous system depressant.
The plant must be used with caution and never without the supervision of an experienced practitioner. Even normal doses can cause drowsiness while excess causes restlessness and overdoses can cause death from cardiac paralysis although some scholars doubt this aspect.
A homeopathic remedy is obtained from the plant which is used in the treatment of chronic catarrh, cough, swollen liver, flatulence and urinary tract disorders.
Among other uses it is reported that an extract of the leaves is used as an ingredient in commercial cosmetic preparations as a skin conditioner.

Method of Preparation –
Lactuca virosa is a plant that is used both in the food and medicinal fields.
In the food field, the tender leaves can be consumed raw or cooked, however caution is advised, due to some toxic effects.
From the seeds an oil is obtained which is used in the kitchen.
The lactucarium, present in the plant, is harvested commercially by cutting off the heads of the plants and scraping the juice into porcelain pots several times a day until the plant runs out.
An infusion of the fresh or dried flowering plant can also be used.
The plant must be used with caution as normal doses can cause drowsiness while excess causes restlessness and overdoses have given lethal results in some cases.
The sap has also been applied externally in the treatment of warts.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://bs.plantnet.org/image/o/8f9e97552f89bb48b1862770f932eea45d515ff2

Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.