Another largish tomb to digest. Book 5 is all about plants.
It starts off with the simplest of plants like mosses and so on, and works its way through the whole field. There is quite a lot of detail, and the start of the book I find rather heavy going as it introduces all the different types and their various ways of reproducing. Its a lot of alphabet soup here as all manner of new terms and structures are described in quick succession. Everything under the sun has a new somethingaphore or blastothingy
However it does get into more of the stuff I like, such as the mechanisms of photosystems and the molecular detail of transport systems and such like. Yes, I know I'm weird but thanks for asking! CAM and C4 plants also get a mention - you'd have though RuBisCO would have sorted itself out by now, I mean its had several hundred million years to get it right, if not several billion!
Then we get into water transport, stomata and xylem, followed by phloem and sugar transport and all that stuff. There is a lot of detail on this and its all quite interesting, but again there are a lot of words to learn. Sieve tubes, companion cells, pressure-flow, cohesion-tension theories etc.
After that we explore the flowering mechanisms, and also re-examine the auxin theory of phototropism. This has changed substantially since I last looked at it, it seems the early researchers came to premature conclusions based on reasonable evidence.
It rounds off with a section on microbes, seeds and interactions between them.