Perhaps I'm just on the low end of botanical curiosity, but I wouldn't ever have made that leap myself. If you'd asked my younger self 'what is a shrub?' I woul

Perhaps I'm just on the low end of botanical curiosity, but I wouldn't ever have made that leap myself. If you'd asked my younger self 'what is a shrub?' I would have said 'uh, like a small bush?'. It would never have occurred to me to pursue the thought any further: my mind interfaced well with mechanical and electrical and computational things, and not at all with living things! I'd just about struggled through introductory Biology at school but was never particularly interested in it. So - yes, if you'd asked me whether all trees had a single woody ancestor, I would probably have said yes. I'd come across the idea of convergent evolution in animals before, but at least convergently evolved animals were really obviously different. Trees were obviously all the same thing: big trunk, some branches, green bits on the end. Some of them were coniferous and some deciduous, but I would have guessed that was a far-back ancestral split. I had no idea that tree ferns even existed! Anyway, the conclusion of this very rambling story is that I started dating an horticulturist and rapidly learned an enormous number of mind-melting facts about plant biology. But I still remember knowing absolutely nothing.