I forgot to mention hawthorn (Crataegus) before. It's a genus of spiky shrubs that produce a fruit...
Beware that hawthorn can turn your whole pasture into a thorny labrynth! It did this to a neighboring property on San Juan Island, WA (where many fields have hawthorn hedges) from bird-scattered seeds. Then it spread into our pasture after we stopped grazing and haying it. It would probably take a bulldozer now to clear it. But we sold the property, and now I'm trying vigorously to control the few hawthorns coming into our new pasture.
