From Bob Ladd, Edinburgh, UK
It is interesting that plants communicate chemically, but your use of “word” and “sentence” metaphors is misleading. Plants may combine different chemicals to mean different things, but there is no plant analogue to the way we combine words to make sentences. Each chemical combination has only a stand-alone meaning.
The sentence metaphor would be valid if one chemical meant “attack” and it could be combined variously with others that meant “cutworm”, “aphid” and so on to yield combinations with derivable meanings like “cutworm attack”. As far as I know, that property, known as compositionality, has developed in only one biological communication system – ours.
