Which heath pea would that be?

by Jeremy Cherfas on February 25, 2013

Over at another place, I’ve been looking into the botanical confusion surrounding that essential of Roman cooking, mentuccia, which is not pennyroyal. And lest people are tempted to say, as they have before, “Get a life,” here’s another splendid example of the perils of common names. And these are in the same language.

Luigi noticed this strange website which is both touting the benefits of and seeking supplies of a plant it calls the heath pea. Why? Well, there are records of Scottish highlanders suppressing their appetites during hard times1 by eating the heath pea’s tubers. The heath pea site helpfully provides loads of pictures and other information to help people identify the correct species. But here’s the thing. There are at least two plants that occasionally go by the name heath pea: Vicia ervillea and Lathyrus linifolius. Both are also sometimes called bitter vetch. And I certainly wouldn’t have known the difference had it not been for a blog post by one ferrebeekeeper, ‘fessing up to having got the two mightily confused.

Vicia ervillia is one of the founder crops, first domesticated in the Middle East all those years ago, and still cultivated there. But Lathyrus linifolia is the one the Scots should be looking for.

Doubly confusing, it seems that the Vicia causes lathyrism and the Lathyrus doesn’t. As it happens, we have an expert on Lathyrus and Vicia among our regular readers, and I don’t doubt that he’ll be along in just a second to sort things out properly.

Footnotes:
  1. Must have run out of Caledonian tomatoes. []

{ 5 comments… read them below or add one }

Mike Jackson February 25, 2013 at 12:22 pm

Possibly (probably) Lathyrus tuberosus, also referred to as heath pea. And I’ve seen Scottish references to it as well. But much more common in the southern part of the British Isles.

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Dirk Enneking February 28, 2013 at 9:36 pm

Mentuccia seems to be used for mint and other Labiatae.

There is no doubt about the toxicity of several Lathyrus species. The current problem is the lack of an experimental bioassay to reproduce the neurotoxic symptoms caused by excessive consumption of Lathyrus sativus, L. cicera and L. clymenum. These species produce the non-protein amino acid beta-ODAP. The same compound is present in Ginseng preparations and praised as dencichine for its beneficial effects.

A whole group of Lathyrus species produces an acutely toxic amino acid diamino-butyric acid (DABA). Lathyrus sylvestris, a forage crop, is an example of these. Don’t consider eating any of this group.

GRIN accepts the heath pea as Lathyrus linifolius (Reichard) Bässler

Joan Thirsk (2007) in Food in Early Modern England: Phases, Fads, Fashions 1500-1760, Hambledon Continuum, London p. 165-166 provides details on Lathyrus linifolius (bitter vetch or caremyle) as famine food. The reference from the 1700s is also provided: “Sir Robert Sibbald published a pocket-book treatise of 24 pages entitled Provision for the Poor in Time of Dearth and Scarcity, where there is an Account of such Food as may be easily Gotten when Corns are Scarce and Unfit for Use. This essay was first published in 1699, ran to a second edition in 1703, and survives in a reissue of 1709 in the British Library.”

The phytochemical dictionary of the Leguminoseae lists various flavonoids for the leaves and the non-protein amino acid homoarginine for the seed. No data on toxins in the tubers.

Vicia ervilia Willd. (bitter vetch, yeros, ingrassabue, kersannah, Erwe) is indeed implicated in causing neurolathyrism, including the infamous epidemic at Ainos described by Hippocrates.

During famine at Ainos those who continuously ate legumes developed impotence of the lower limbs. This persisted. Others, who ate Vicia ervilia suffered pain in their knees.” Ainos was a village in Thrace, the epidemic [dated to the last decade of the 5th century B.C. or first part of 4th century]
source: Grmek, M. D. 1980 La légende et la réalité de la nocivité des fèves [Legend and reality in relation to the toxicity of Vicia faba]. Pubbl. Stn. Zool. Napoli. II 2(1):61-121.

Despite its potential to do harm, Vicia ervilia appears to have been domesticated as a drought tolerant food crop (Miller and Enneking, in press). My own experiments with hot aqueous leaching of the bitterness have yielded a product of detoxified whole seeds with pleasant nutty flavour (residual bitterness) and versatile culinary uses.

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Jeremy Cherfas March 1, 2013 at 1:16 pm

Over at a link-farm site-scraper someone who calls himself (making assumptions, I know, but I’m confident …) Bitter Vetch has commented on this post, as follows:

Hi!
I’ve been growing and researching Bitter Vetch (lathyrus linifolius) for some 5 years now so its a subject I can bore on for hours. One small pedantic correction is that the two plants share the common name Bitter Vetch, but not the name Heath Pea.

Vicia Ervilia is a drought resistant forage crop of north Africa and the Southern Med, the seeds of which can be best described as being like a combination of a large grape seed and a chick pea – because they are quite substantial in size, in times of famine people have resorted to eating and feeding the seeds to livestock with the net result that it causes lathyrism.

By comparison the seeds of Lathyrus Linifolius are tiny, spherical and about 2mm in diameter. Each year I hand harvest the seeds from my bitter vetch crop and eating them simply wouldn’t be worth the effort. They also seed in May/June whereas the Vicia Ervillia I grew (in northern England) produced seed in late summer.

Besides the shared common name, one further reason for the two plants regularly being conflated into a muddled “hybrid” is that they both come to the fore in times of food shortage. As it grows Lathyrus Linifolius produces a series of tubers which, when dried, taste like a sweet licquorice – chewing on this suppresses the appetite. In the days before the potato, Scottish Highlanders used to harvest and dry the tubers so that if the crops failed they had something to take away the hunger pangs as they struggled through the winter.

I’ve eaten the tubers and they are every bit as effective as the history books suggest.

Hope this helps

I suppose so.

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Rhizowen March 1, 2013 at 1:36 pm

There’s a simple and fail-safe way to distinguish Lathyrus linifolius and L. tuberosus: plant both in a common garden experiment in Cornwall and wait a few weeks. The plants with intact leaves and flowers are L. linifolius; the barely visible, leafless, slug-demolished stems are those of L. tuberosus. I wonder whether susceptibility to slug herbivory has anything to do with the very limited distribution of L. tuberosus in the UK?

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Dirk Enneking March 2, 2013 at 1:44 am

Brian Moffat (2000) ‘A Marvellous Plant’ The Place of the Heath Pea in the Scottish Ethnobotanical Tradition. Folio – National Library of Scotland – Issue 1 – Autumn 2000, pp. 13-15
http://www.nls.uk/media/22680/folio01.pdf

@Rhizowen – my snails (Helix aspersa) don’t like bitter vetch (Vicia ervilia) seed flour. Your observation hardens the case for bitterness in both plants acting as a mollusc deterrent.

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