My homeland, is a volcanic island; the soil is a basalt clay. It's, not great for a lot of things but root vegetables, especially potatoes and carrots (don't even get me started on the massive yield carrots planted in this soil provides ) love it. Fungus, certain kinds of grass, some trees (evergreens grow just fine), certain flowers, a lot of toxic plants, for sure.
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Of course, my homeland has a temperate climate overall, and is multi-terrain; it's not a typical volcanic island by any means.