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Daucus carota subsp. carota
L., Wild Carrot

Account Summary

Native, rare. Eurosiberian southern-temperate, but very widely naturalised and now circumpolar.

1950; MCM & D; Clonmaulin near Clontivrin.

April to November.

Growth form and preferred habitats

This subspecies is a monocarpic, biennial or short-lived perennial (perhaps very rarely, an annual), that has a slender, whitish tap-root, less than 5 cm in diameter, becoming woody with age – quite unlike the familiar, closely-related Cultivated Carrot (subsp. sativus (Hoffm.) Arcang.), with its more swollen, fleshy, orange, edible root (Dale 1974; Sell & Murrell 2009). The flowering stem of subsp. carota is solid, frequently coloured red or purple where it arises from the basal leaf rosette, and it varies in height from 10-120 cm. The basal rosette leaves are heavily dissected, 2- to 3-pinnate, fern- or parsley-like, but ± bristly hairy, and they range from 5-40 cm in length.

Wild Carrot appears on moderately disturbed dry, open or bare, sandy, gravelly or stony ground in sand-pits, waste ground and quarries, or in short, open, well-lit, patchy turf. Usually this means it appears in unmanaged rough grassland on dry or well-drained, rather infertile, mainly calcareous, typically wayside situations. It avoids acid soils below pH 5 and has a bias towards infertile habitats (Grime et al. 1988, 2007). Experimental work suggests Wild Carrot grows faster, becomes larger and regenerates and survives clipping or grazing better on fine textured, somewhat damper soils (Harrison & Dale 1966).

Until it is mature and capable of initiating flowering, the Wild Carrot plant exists as a compact rosette of basal leaves that is easily overgrown by taller, more robust dominant species. Thus, D. carota subsp. carota usually only manages to persist in short turf or open sites in ungrazed or under-used pastures in situations where dominant species are somewhat restricted by other environmental factors, such as low nutrient levels or lack of moisture. The established strategy of the subspecies is categorised as intermediate between stress-tolerant ruderal and the more balanced C-S-R (ie Competitor-Stress-tolerant-Ruderal) (Grime et al. 1988, 2007).

Requiring a growth period of more than 120 days frost-free, in B & I it is confined to lowland situations below 450 m. Wild Carrot is indifferent of photoperiod length, being adventive throughout warmer parts of the world and occurring from C America and Mexico to ground north of 65°N in Sweden (Dale 1974). It prefers full sun and when shaded its vigour drops. In deeper shade, its reproductive method may change to that of a short-lived perennial (Harrison 1965). In Europe, Wild Carrot showed a preference for medium to high levels of nitrogen, but was indifferent to phosphate levels on well fertilised sites in hay meadows in Germany (Kϋhner 1951, cited in Williams 1968, quoted in Dale 1974). It is also much less closely associated with calcareous soils in Europe than is the case in Britain, so that it might even be described as indifferent to lime on the continent (Dale 1974).

Herbivory

The characteristic carrot odour is perceived when tissue of any part of the plant is crushed. Milk of dairy cattle can become tainted when large amounts of Wild Carrot are present in pasture, but this is very unlikely today and it has never been reported that cows graze upon it from choice. However, the digestibility and nutritive value of Wild Carrot foliage is similar to that of legumes and, therefore, it should be tolerated in pastures among plants of low nutritive value. Cattle, horses and sheep will all graze Wild Carrot (Harrison & Dale 1966; Dale 1974). Compared with the leafy basal rosette, the flowering shoot is particularly conspicuous and therefore much more vulnerable to grazing damage or destruction (Dale 1974).

Flowering reproduction

D. carota subsp. carota is completely dependent on seed for survival, increase and dispersal. The timing of flowering in a maturing plant appears to be triggered by a combination of rosette size and recent growth rate. An increase in size but a decrease in relative growth at the end of the summer is associated with an increased probability of flowering in the following growing season for short-lived monocarpic species, including D. carota subsp. carota. Year of flowering also has a genetic component (ie maternal phenotype – annual, biennial or triennial) and nutrient supply certainly also plays a part in determining growth and the timing of the switch between vegetative and reproductive growth (ie bolting). In an experimental study, maternal phenotype influenced the year of flowering both directly and indirectly through growth. Plants die after bolting regardless of whether or not they set seed (Lacey 1986).

The compound umbels are terminal and andromonoecious (ie they contain both male and bisexual flowers); the bisexual blossoms are protandrous, ie the pollen matures before the stigma does, thus favouring cross-breeding. Umbels normally consist of over 1,000 white flowers, developing from a convex dome into a flat circle at time of fertilisation. The flat white inflorescences often have one or more central flower(s) that are slightly enlarged and coloured black, red or purple. This observation and their existence is something of a puzzle to explain, and since at least the middle of the 19th century there has been an ongoing search for their purpose, if any (Hoekstra 1997). It has been suggested the dark florets may have adaptive functions, such as mimicking insects (including beetles), visiting the inflorescence, possibly to discourage herbivory, pollen and nectar theft, or alternatively, to attract additional pollinators to the plant, perhaps by indicating the presence of food or opportunities for meeting and mating. Charles Darwin dismissed the dark flower spot as a vestigial remnant of some redundant function, and he just might be perfectly correct. However, the debate continues and the current author (RSF) cannot yet see where it is taking us, since insect visitors attending the inflorescence are already legion, without the need for any enhancing mechanism, simple or complex, that requires further explanation (Dale 1974).

After fertilisation the inflorescence becomes contracted into a concave, cup- or bird's nest-like mass during the period of fruit maturation. Eventually, the nest-like mass flattens out again during seed dispersal.

The outer flowers in umbels are surrounded by a whorl of green, finely-divided bracts. A large flowering plant individual may produce up to 100 umbels during the flowering season from June to August. Axillary leafy, flowering stalks are produced in succession until the autumn, when the plant dies (Dale 1974; Sell & Murrell 2009).

Cross-fertilisation is the norm and a very wide range of unspecialised insect visitors are attracted by abundant, freely available pollen and nectar to carry out pollination. Should crossing fail for any reason, the flowers can self-fertilise (Dale 1974).

As with other umbellifers, the schizocarp fruit splits into twin, single-seeded mericarps (or achenes), 3-4 mm long × 2 mm wide, for dispersal (Dale 1974). Man and his activities represent the major vector transporting the bristly, spiny-looking mericarps over long distances, although wind and attachment to animal coats are also definitely involved in local dispersal (Salisbury 1964; Lacey 1981). Lacey showed experimentally that animal coats rougher than those of mice and rabbits can hold the spiny, barbed seed long enough to assist dispersal. She also proved that wind in autumn and winter can carry seed long distances across snow and frozen ground (Lacey 1981). Seed can also be ingested by browsing animals and can pass undamaged through the digestive tract of a horse (Salisbury 1964). Seed is long-persistent in soil, surviving for more than five years (Thompson et al. 1997).

Variation

D. carota is an extremely variable, environmentally plastic and genetically polymorphic species, to the extent that eleven subspecies are described in Flora Europaea (V.H. Heywood, in Tutin et al. 1968, 2, p. 374). Most wild Daucus forms occur in SW Asia and the Mediterranean region, a few in Africa, America and Australia. All wild forms investigated in Asia, Asia Minor, Japan and the USA have the same chromosome number as their European relatives (2n=18). Neither polyploidy nor structural changes in chromosomes seem to have played a role in the differentiation of the species (Whitaker 1949; O. Banga, in: Simmonds 1976). The Iranian Plateau (Afghanistan, Iran and Pakistan) is one of the areas where subsp. carota shows the greatest variation and has been suggested as a possible source of the species origin. The roots vary in their degree of ramification, fleshiness and colour: some are white and others coloured in varying degrees by anthocyanin (O. Banga, in: Simmonds 1976; https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:841063-1 website viewed 29 January 2022). Subsequent breeding and development of the modern, larger, orange, fleshy, western carotene carrot (subsp. sativus (Hoffm.) Arcang.) was carried out in the Netherlands in the 16th and 17th centuries (Heywood 1983 – abstract only viewed).

Only subsp. carota and the cultivated subsp. sativus occur in NI and there is very little chance of them inter-breeding. There are a few stations for the coastal subsp. gummifer (Syme) Hook. f. in SE Ireland and again in W & S Britain (Preston et al. 2002).

Fermanagh occurrence

In Fermanagh, Wild Carrot has been recorded in 16 tetrads (3%), ten of them with post-1975 dates. In landlocked Fermanagh, only twelve stations for Wild Carrot have been recorded since 1988. The two most recent finds, where the plant was seen in any quantity, were beside a stream in Cross Td, on the northern outskirts of Enniskillen, where 25 plants were counted in September 2001, and outside the quarry gate at Coagh, 5 km N of Enniskillen, where ten seedlings were found in October 2001.

British and Irish occurrence

Wild Carrot is a common and familiar plant in coastal sites in NI, but rather rare and possibly declining inland. The distribution pattern of the plant elsewhere in Ireland is common on coasts, rarer inland, but subsp. carota becomes more widely recorded southwards.

D. carota subsp. carota is widespread in lowland Britain, although again it becomes increasingly scarce and coastal north of the Humber-Severn line. The hectad map in the New Atlas suggests a decline in Scotland, both inland and along the E coast. A smattering of red symbols on the same map reflects the fact that nowadays D. carota subsp. carota is sometimes included in wild flower seed mixtures that are increasingly sown in amenity and garden situations (Preston et al. 2002).

European and world occurrence

Carrot is a cool weather plant (O. Banga, in: Simmonds 1976). Wild Carrot is widespread in Europe south of the Baltic, plus in temperate Asia and North Africa (Tutin 1980) but it has been introduced to many areas around the world and become so widely naturalised that D. carota s.l. is now a discontinuous circumpolar southern-temperate taxon (Hultén & Fries 1986, Map 1434; M. Southam, in: Preston et al. 2002). Having said this, it is such a variable species aggregate with so many subspecies distinguished, it is difficult or often impossible to determine whether an occurrence is indigenous or not. It is known, however, that subsp. carota has been introduced and become naturalised (sometimes abundantly) in N America and in New Zealand (Dale 1974; Webb et al. 1988).

Uses

In Classical times, the white-rootstock carrot we know as Daucus carota subsp. carota was well known and is mentioned by Greek and Latin writers, although there sometimes is a measure of ambiguity regarding whether they are referring to carrot or parsnip. However, by the time Dioscorides described the plant in the first century AD, he gave an accurate description of the carrot dealt with here (Grieve 1931).

The western, bright-orange coloured, fleshy, carotene Cultivated Carrot was first introduced to England by Fleming refugees in the reign of Elizabeth I (1553-1603). Previously, the Wild Carrot was cultivated and used both as a vegetable and for medicine although the root was small and spindle-shaped, whitish, slender, tough and had an acrid, unpleasant taste.

In herbal medicine, the whole Wild Carrot plant had uses and was considered more efficacious than the cultivated form of the plant (Allen & Hatfield 2004). It was considered a diuretic, stimulant and 'deobstruent'. A tea-like infusion of the whole herb was considered an active and valuable remedy in the treatment of dropsy, chronic kidney disease and diseases and affections of the bladder. A strong decoction was used to break up stones and gravel and was good in treating flatulence. The seeds were described as carminative (ie used for flatulence) and stimulant and were useful in treating flatulence, windy colic, hiccough, dysentery and chronic cough. They were also believed to clear obstructions of the vicera and useful for jaundice and scorbutic disorders (ie the treatment of scurvy). An infusion of the root was also used to ease constipation (Grieve 1931).

Grieve also reported the old belief that a poultice made from the roots helped relieve the pain of cancerous ulcers, and the leaves applied with honey, cleansed running sores and ulcers (Grieve 1931).

Names

The name 'Carota' was first used by Athenaeus around 200 AD and it was Galen (second century AD) who added the name 'Daucus' to distinguish the carrot from the parsnip (Grieve 1931). An additional eleven English common names for 'Wild Carrot' are listed by Grigson (1955, 1987). 'Bird's Nest' is a name taken into English from the German, referring to the nest-like contracted umbel fruit. 'Bee's Nest' and 'Crow's Nest' are obvious alternatives derived from the same idea. The names 'Kex' and 'Keggas' are associated with plants with hollow stems in general and often to other umbellifer species in the Apiaceae. A Scottish name, 'Curran-Petris', denotes a carrot root, 'curran' being Scots gaelic for 'carrot' (Britten & Holland 1886). The name 'Eltrot' or 'Eltroot' is given to several umbellifers including D. carota and is said to be from the Anglo-Saxon 'eald', meaning 'old', and root, or from 'elt', meaning 'a young pig', and root. The name 'Rantipole' refers to the bunch of leaves that compose the basal rosette (Britten & Holland 1886).

Threats

None.