Sure, though the mushrooms are in the part of the produce section labeled “vegetables” which is generally defined in reference to plants (as is the other part of the produce section, but that’s neither here nor there). The word “plant,” like most words, admits multiple related meanings. Some of these are lay, and some of them are technical. The lay meaning of “plant” clearly includes fungi (as did the scientific definition, once). Note that the OED still attests both senses without marking the broader sense as obsolete, informal, or otherwise – just “general”:
This doesn’t make the “general” sense provided here wrong. It is completely okay for a lay definition and a technical definition (or two related but distinct technical definitions) to diverge in meaning. Language is pragmatic. What the word “plant” means is defined by how it’s used in practice. And in practice, in non-technical contexts, the term “plant” is often inclusive of fungi – q.v. the very article we’re discussing.
The scientific definition of “plant” is, of course, better for the uses science puts it to, i.e. descriptive classification of biological relations, facilitation of formal knowledge discovery, etc. But it is not intrinsically more correct or intrinsically better than any other definition. To demand a technical definition outside of its context just denies the reality of how language works.
