A quick google search tells me that a few other plants I have heard of are gathered from the wild. These can separated into three categories of ignorance as follows...
1. Plants I associate with specialist delis and middle class luxuries; I had no idea these were things one could find in the UK free of charge:
Sorrel, comfrey.
2. One plant I didn't think could be grown in the UK, let alone in the wild:
Plantain.
3. Trees that I can recognise but have never heard of being used as food:
Birch, ash.
That gives me 11 known edible species (of which 7 I could collect with confidence) and 3 species I could recognise but didn't know were edible. And I have never actually seen any of these for sale in a shop.
I guess I represent a relatively ignorant subsection of the European population, though: Studies of wild plant species found in Europe cite 123 species known in Spain, of which at least 8 species continue to be collected, 58 species collected in Poland (collection has undergone a significant decline in recent decades), 133 species (including fungi) in central Italy, 7 species in Sicily (consumed by less than a quarter of the population, and more frequently by women)…whilst searching, I found studies emphasising the nutritional value of wild vegetables, particularly in regard to their role in complimenting a diet based on cultigens. I also found that many studies referred to wild vegetables as 'under-utilised', in both developed and developing countries.
However, here in Japan, many of the people I meet in the countryside can reel off many, many edible wild plant names, far exceeding the numbers cited above, and they continue to collect them by default each year. Far more than my 9 species.. For example, Japanese Wikipedia gives me 42 'common' species, a research article detailing the species found within a single university campus has descriptions and photos of 60 species, and the same article references a text that will apparently yield descriptions of over 1300 species growing in the Japanese wilderness. Also, a recent trip to a shop ('Green farm', in Ina city) in Nagano prefecture even gave me the opportunity to purchase all sorts of wild plants. Here are some examples:
Perhaps the incorporation of seasonal wild vegetables, along with edible insects, into the everyday diet of people across the world, would have positive effects on public health - including not only human health, but also that of the environment in which we live, and that of the relationship we have with the environment that surrounds us.
And finally, looking into all of this (mostly as part of preparation for the Oxford Student Global Food Security Conference in May) has left me with another question: Is my ignorance of edible plants representative of people of my generation in the UK? What about my Japanese equivalents - do people in their 20s in contemporary Japan know about the 1300 vegetables they can collect for free from the forests? What about my Zimbabwean friends? These questions have caught my attention, and I'll write more when I find the answers. Meanwhile if you have any edible plant collecting/cooking stories from the recent or distant past, please email me - especially if your memories involve species or practices I've not mentioned here!