Thapsia Maxima

''Thapsia villosa'', commonly known as the villous deadly carrot, is a species of poisonous herbaceous plants in the genus ''Thapsia''. It grows to about in height. It has pinnate hairy leaves with sheath-like petioles. The flowers are yellow in color and borne on compound umbels. They develop into fruits with four wings characteristic of the genus. It is native to southwestern Europe and northwestern Africa surrounding the Mediterranean Sea. The plant was used extensively for traditional medicine since around the 3rd century BC.

Taxonomy

''Thapsia villosa'' was first described by Carl Linnaeus in ''Species Plantarum'' (1753). It is classified under the genus ''Thapsia'', subfamily Apioideae, of the carrot and parsley family Apiaceae. Two varieties are recognized: ''T. villosa'' var. ''villosa'' and ''T. villosa'' var. ''dissecta''.

The generic name ''Thapsia'' is derived from the Ancient Greek name θαψία (''thapsía'') for the members of the genus. The Greeks believe it to have originated from ancient Thapsos in Sicily. The specific epithet is from Latin '' villōsus'' ("hairy" or "shaggy").

It is commonly known in English as the ' villous deadly carrot' or simply 'deadly carrot'. It is known under a large number of common names in other languages, including ''bu-nefar'' in Arabic; ''zumillo'' and ''cañaheja'' in Spanish; ''baladra'' in Catalan; ''croca'' in Majorcan; ''turbit-da-terra'' in Portuguese; ''bermidor'' in Basque; ''turbith bâtard'' in French; and ''turbito falso'' in Italian.

Description

''Thapsia villosa'' is a perennial herb growing to a height of . It has a robust and smooth tapering stem about in diameter, arising from a thick root resembling a white carrot or turnip.

The leaves, like the name of the species suggests, are hairy. The leaves around the base of the stem have well-developed sheath-like petioles about wide. Like the leaves, they are also hairy. They are whitish, yellowish, green, or (rarely) purple in color. The leaf blades are triangular to deltoid in shape and are pinnate, subdivided once to thrice. The last leaflet subdivision is usually about wide in ''T. villosa'' var. ''villosa''; while they are only about wide in ''T. villosa'' var. ''dissecta''. The margins of the leaves are curled ( revolute) with small teeth-like and triangular serrated edges, each tipped with small spike. The main leaf midrib (rachis) is densely covered in hair and light to dark green on the upper side, while it is smooth and grayish to greenish on the underside. The leaves are largest at the bottom and progressively become smaller the higher they are on the stem. In the upper parts of the stem, the leaves are often reduced to nothing more than petioles which form sheaths around the stem.

Like other members of the genus, the inflorescence of ''Thapsia villosa'' is a compound subhemispherical to globose umbel. It has 9 to 29 spokes and is about in diameter. Bracts are usually absent, though in rare cases, one to three may be present, each around in length and lanceolate in shape. The umbellules are hemispherical to globose. Bracteoles are also usually absent, though rarely 1 or 2 may be present. Each umbellule has about 18 to 43 flowers, each with five bright yellow elliptical petals. The fruits are oblong and around long and wide. When mature, they are light to dark brown in color with four yellowish to brownish wings characteristic of the genus. The main umbel has hermaphroditic flowers, containing both stamen and pistil. Smaller umbels may develop from the sides of the stem which usually contains only stamens. These umbels wither away quickly.

''Thapsia villosa'' is highly variable in morphology. The two varieties, ''T. villosa'' var. ''dissecta'' and ''T. villosa'' var. ''villosa'' are usually distinguished by how many times the leaf subdivides into leaflets. ''T. villosa'' var. ''dissecta'' has leaves that are deeply subdivided two or three times into narrow and small leaflets. ''T. villosa'' var. ''villosa'', in contrast are usually subdivided only once or twice. However, there are numerous intermediate forms between the two varieties and distinguishing between them can be very difficult. The diploid chromosome number (2n) of ''Thapsia villosa'' is 22, 33, 44, or 66.

Ecology

Unlike most members of the family Apiaceae, ''Thapsia villosa'' flowers early, during the months of May, June, and July. The flowers are pollinated by a variety of insects. The flowers develop into winged fruits that dry out around August, while other members of the family are usually still in bloom.

Distribution and habitat

The native range of ''Thapsia villosa'' extends from southern France and the Iberian Peninsula (Spain, Portugal, and Gibraltar) to northwestern Africa (Morocco, Algeria, and Tunisia). It has also been introduced into Corsica. They can be found growing at altitudes of above sea level in scrublands, clearings, and near recently disturbed land like roads or cultivated fields.

In its native range, it is frequently confused with the similar-looking ''Ferula communis'', the giant fennel. ''Thapsia villosa'' and ''Ferula communis'' share some common names in Spanish like ''cañaheja''. Reports of ''Thapsia villosa'' in the Balearic Isles is likely the result of confusion with '' Thapsia gymnesica''.

Toxicity

''Thapsia villosa'' is highly poisonous. Skin contact with the roots can cause severe itching and swelling.

Uses

Traditional medicine

The medicinal properties of the members of the genus ''Thapsia'' were recognized as early 300 BC. In traditional medicine, the roots of ''Thapsia villosa'' were used as a purgative and emetic. Resin from the ''Thapsia villosa'' was used as a blister-producing agent (vesicant) or a counterirritant, similar to resin derived from ''Thapsia garganica''. In Spain, the resin is also traditionally used in Segarra as treatment for scabies. Poultices made from root bark infused with oil was used as a pain-reliever and for treating rheumatism. These were also used in Salamanca for treating cracks in horse hooves.

Traditional medicinal uses of the plant, however, are now considered largely ineffective and highly inadvisable due to the danger posed by the poisons of ''Thapsia villosa''.

Medical research

Along with ''Thapsia garganica'' and '' Thapsia transtagana'', ''Thapsia villosa'' var. ''villosa'' contains C-19 terpenolides with strong SERCA-inhibiting properties ''in vitro''. They are of interest to medical researchers for their potential in treating neurodegenerative disorders like Alzheimer's or Parkinson's disease.

Other uses

Poison from the roots of ''Thapsia villosa'' is traditionally used by fishermen in Catalonia as an ichthyotoxin for stunning fish, making them easier to catch. Extracts from the root bark of ''Thapsia villosa'' have been used since ancient times as a yellow dye. In the 18th century, yellow dye from the flowers were used to color wool. ''Thapsia villosa'' are also grown as ornamentals for their bright yellow flowers.

References

External links

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{{Taxonbar, from=Q537992

Medicinal plants
Apioideae
Plants described in 1753
Taxa named by Carl Linnaeus