When out foraging, there are several plants you need to avoid. Foxgloves, poppy, ivy, buttercups, bluebells and nightshade have already been mentioned, and so has ragwort.
Ragwort is a biennial. This means it has a two year life cycle and its appearance is different in each year. In the first year it is low-growing in florets, with dull, mid-green, crinkly leaves. In the second year it grows taller and has florets of bright yellow daisy-like flowers. It’s equally poisonous in both forms and must be strictly avoided.
There are two types of nightshade, Woody Nightshade – more attractive, small purple flowers and bright red berries, and Deadly Nightshade, red flowers, orange berries. Both are toxic but the second more so.
Also toxic and not to be fed to rabbits are arum, bryony and hemlock. Unfortunately hemlock is easily confused with cow parsley, which rabbits enjoy very much. Look at the stems. Hemlock has purply/pinkish spots on the stems, shinier leaves than cow parsley and is a brighter green. If in doubt leave it. Hemlock causes a horrible death very quickly after being eaten.
Other plants to leave when foraging are Aconite, Celandine, Corncockle, Cowslip, Dock, Fool’s Parsley, Henbane, Hedge Garlic, Ivy, Spurge, Traveller’s Joy, Tree Lupin, Wild Garlic and Wood Sorrel.