Pignut: Conopodium majus (Golian.) Loret. Synonyms Bunium flexuosum - Stokes. Conopodium denudatum - Koch. Arnut, (from Old Norse Jarðhnot, earthnut) Arnuts, Badman’s beard, Braonan bhuachail (shepherd's drop/nut), Catnuts, Cnò-thalmhainn, Cronies, Curluns (Kirk, Wigt), Deli’s bread, Deli’s oatmeet, Earthnut, Earth Chestnut, Gernut, Gourlins, Gowlins, Hornecks, Knot-girse, Knotty Meal, Lousy arnuts, Lucy arnut (Perth, Aberd), Lucy aunt, (Fife), Pignut, St. Anthony's nut (from the St. Anthony of Egypt, 251 AD - 356 AD being patron of swineherds), Swine bread, (Inv), Truffle, also many other regional names in U.K. and Ireland.

Once, not so very long ago, country children on their way home from school in summer would squat for hours on the roadside digging for pignuts with sticks or pocket knives. How the world has changed, the law has banned both digging up plants (unless you do it with a JCB) and the carrying of knives, and the manipulated paranoia of parents ensures no child walks home down lonely country roads. Furthermore as the plant is in that 'Russian Roulette' genera of the Umbelliferae, I doubt many modern schoolchildren could safely identify it. The thin root needs to be carefully followed through the maze of other plant roots to trace it to the small tuber. So now are we trying to create a world where in several most important respects we will stay infants all our lives? We will be ignorant of how to feed ourselves, lacking in skill with the most basic of tools and incapable of making valid risk assessments and appropriate responses to danger. Is this the rulers' dream of a totally subservient, malleable and dependent populace?

Shakespeare : ‘The Tempest’: Caliban "And with my long nails I’ll dig up pignuts."
John Peely, 1694 : "Nuts peeled, boiled in fresh broth, pepper, nourishing stimulates the venery"
Snooty Victorian botanist : "Better fitted to the digestion of the respectable quadrupeds, whose name they share than for Christian bipeds of tender years.".

The old wives tale says: if you eat too many, you will catch head lice, I can see how this arose. If one child, in a squatting group peering intently into the ground, already had head lice then they would all stand up with them.

Non-medical uses of pignut
Roots cooked or raw. (said to be good roasted with rabbit). Pigs and Brown Bears both very fond of them, can smell the tubers when plant dormant. Pigs have been trained to find pignuts, like truffles. May once have been cultivated, but not really suitable for arable land. They taste chestnuty.

Medicinal uses of pignut
None given in my main source. However Gerard's Herbal mentions that 'There is a plaister made of the seeds hereof, whereof to write in this place were impertinent to our historie' this makes me wonder what on earth it was for that he so objected to. An ethnobotanical work also lists the following historic uses: to purify blood, to decrease urine, treating tumours and cancers.

Sources:
ONLINE ENCYCLOPAEDIA THE UMBELLIFERAE (CARROT/PARSLEY) FAMILY OF THE BRITISH ISLES http://www.spookspring.com/Umbels/Pignut.html
Plants For A Future, www.pfaf.org/index.html,
Flora Celtica, www.floraceltica.com/, Flora Celtica is an international project based at the Royal Botanic Garden Edinburgh, documenting and promoting the knowledge and sustainable use of native plants in the Celtic countries and regions of Europe.