Chenopodium album L. agg., Fat-hen

Account Summary

Growth form and preferred habitats

In Fermanagh, Fat-hen is a frequent summer annual weed of disturbed ground and less frequently of potato fields and root crops and a variety of other open, artificial habitats. It grows on a wide range of soils, especially those of moderate pH and mesic to rather dry moisture status in the lowlands. It totally avoids strongly acid or wetland substrates. Like C. rubrum (Red Goosefoot), this species is essentially a ruderal pioneer colonist of open waste-ground and is, therefore, a poor competitor, unable to persist in closed turf vegetation. It is typically found on heaps of top soil or other forms of loose, recently disturbed surfaces, preferably those that are fertile or at least nitrogen-rich. It begins flowering rather late in the season, in July and August, and is particularly obvious in the autumn when it is fruiting (Williams 1963).

Identification

While phenotypically it is very variable in morphology and reproductive output depending upon growing conditions, C. album is usually less robust, more compact and more mealy-surfaced than the superficially similar Atriplex patula (Common Orache), in which the lower branches of mature plants tend to be opposite rather than alternate. The fruit is enclosed by five equal sepals rather than two large bracts as in oraches.

Stace (1997) details six closely related species that may be confused with C. album, but few or none of these have ever been recorded in Ireland and I am content to consider all local plants as either C. album agg. or C. album s.s.

Fermanagh occurrence

Locally, Fat-hen is quite frequent, having been recorded in 76 Fermanagh tetrads, 14.4% of those in the VC. Considering the collapse to near extinction of arable farming in the area during the last 50 or so years, this is striking evidence of the species habitat range and ruderal flexibility. The continuing presence is greatly assisted by the prolonged dormant seed longevity characteristic of the genus.

Seed dispersal

While there is no special seed dispersal mechanism, some fruits remain on the plant until it dies in early winter, and these may be eaten by animals including birds and the seed transported internally. The seed contains fat, and it was an important supplementary human food source in ancient times. The last meal of the Tollund Man, who was found preserved in a peat bog, was a porridge or gruel containing seeds of Chenopodium and up to 40 other species (Grigson 1955, 1987). Birds (crow, snow bunting and ducks) and other animals including pigs and horses, eat the fatty seed, transport it internally and deposit it with their faeces (Ridley 1930, pp. 359-61). However, the great majority of seed appears to simply fall around the parent plant, giving rise to patches of the plant in following years in moderately disturbed habitats.

Seed longevity

Seed of C. album recovered from archaeologically dated soil samples proved viable after burial for 1,700 years (Odum 1965).

Population vulnerability

Being strictly a summer annual, C. album has no means of vegetative reproduction, or even of seedlings over-wintering since the species is frost sensitive. A late spring frost can seriously affect establishment of the new season's populations, or wipe them out completely. Plants mown, grazed or trampled in the early stages of growth also have no means of recovery (Grime et al. 1988).

British and Irish occurrence

C. album is widespread throughout Britain & Ireland, although less common in the N & W of both islands, and more coastal in both these directions. This is interpreted as due to the wetter climate and the strongly acid peaty soils prevalent in these regions. The distribution has remained stable over most parts of these islands, although it has declined in the west due to the move away from arable agriculture towards pastures (Preston et al. 2002).

European occurrence

While considered indigenous to temperate Europe, C. album has been spread by man and become almost cosmopolitan. It has been transported amongst seed of arable agriculture to the extent that Holm et al. (1977) rank it as the world's worst weed of potatoes and sugar beet. A French botanist has suggested that C. album is one of the five plants most widely distributed in the world (Coquillat 1951).

Names

The genus name 'Chenopodium', is a combination of the Greek 'chen' meaning 'goose', and 'pous', 'a foot', a reference to the shape of the lobed leaves (Johnson & Smith 1946). The Latin species epithet 'album' means 'white', presumably a reference to the white, mealy surface of young leaves. The English common name, 'Fat Hen', which also appears in a German equivalent, refers to the plant's previously frequent usefulness, along with all Chenopodium species, in fattening poultry for the pot. Another common name, 'All good', is also applied to C. bonus-henricus (Good-King-Henry), referring to the usefulness of the plant for both food and medicine.

Grigson (1955, 1987) lists a total of 25 English common names for C. album, underlining the general appreciation given to the plant throughout Britain and Ireland. An interesting one with many variants is 'Milds', 'Milder', 'Miles', 'Myles' or 'Meals', 'Melgs', and so on. It can sometimes appear as 'Meldweed', 'Midden mylies', 'Muckweed' or 'Muck-hill weed', referring to one of its significant waste heap habitats. 'Melde' was the Anglo-Saxon name or word for a food plant that included this species along with C. bonus-henricus and Atriplex patula, all three grown and/or collected wild for use as leafy green vegetables as already mentioned.

Threats

None.

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