Here in Northern California, our spring has already begun. Manzanita is in flower, and the almonds and wild plums are in full bloom. Everything that's not concrete is green, greener than anything you can imagine. Ireland green. It is the Time of Salads.
And no wild salad green is more important than miner's lettuce, Claytonia perfoliata. I took a walk yesterday near Folsom, and within a mile I saw enough of the plant to feed a small town. It is everywhere, so much so that no one can see it. It's become wallpaper, an anonymous part of the green world we're enjoying these days. I watched scores of people pass one of the world's great salad greens without so much as a second glance.
I wonder if they just didn't recognize the plant in its natural setting? After all, next to blackberries and wild fennel, miner's lettuce is probably the most recognized wild edible in this part of the country. Even dazzling urbanites seem to know it, possibly recalling dim memories of summer camps gone by, or of a fancy Alice Waters salad they might have enjoyed at Chez Panisse back in 1989 or something. In gourmet circles, miner's lettuce has become commonplace, an afterthought. It is the iceberg lettuce of wild foods.
Undeservedly so. Miner's lettuce is pleasingly crunchy, mild-tasting, has large leaves, remains tender even when in flower, and is so loaded with vitamins it will cure scurvy. The plant got its name because the Gold Rush miners ate it to stave off the disease, which is caused by a Vitamin C deficiency; they learned this trick from the local Indians, no doubt.
According to a study in the Journal of the American Dietetic Association, 100 grams of miner's lettuce—about the size of a decent salad—contains a third of your daily requirement of Vitamin C, 22 percent of the Vitamin A, and 10 percent of the iron. Combine this with stinging nettles and you have everything you need to revive your system from a winter's worth of heavy meats, dried grains, and roots.
All of these qualities impressed early explorers so much they saved the seeds of Claytonia perfoliata and brought them back to Europe to grow, first as a curiosity, then as a food plant.
Many sources say this happened in 1749, but I have never found any reference to any original source of this date, which I think is a transposition of the real date the plant reached Europe. According to Hortus Kewensis, an 1811 catalog of everything growing in England's famous Kew Gardens, the great Scots naturalist Archibald Menzies discovered miner's lettuce on the West Coast of America in 1794, not 1749, and he brought seeds back to Kew, where it flourished.
I took a look at Menzies' journal of the expedition—he was with George Vancouver on Vancouver's famous round-the-world voyage—and it appears that Menzies actually found the plant along Puget Sound, in current-day Washington, on May 7, 1792:
A little before won the Fog dispersd... we walkd along shore... In this walk I found growing in the Crevices of a small rock about midway between the two points a new Species of Claytonia [a small flowering herb] & as I met with it no where else in my journeys, it must be considerd as a rare plant in this country. I namd it Claytonia furcata & took a rough sketch of it which may be seen in my collections of Drawings.
It is not exactly clear whether this is miner's lettuce or not, but this is Menzies's only mention of claytonia in the journals he kept on the voyage, and there are any number of accounts published before 1820 that mark this as the plant's European provenance.
Miner's lettuce was so important as a source of Vitamin C that the British planted it in Cuba and, later, in Australia. An early 19th-century article I found notes that miner's lettuce was already well-established in Cuba by 1811, and that it was "spontaneously growing" in the Botanical Gardens of Paris. By mid-century it was being sold by seedsmen as a salad green and potherb—and was rapidly becoming a weed in England.