HERE. This seems timely for me to think about, as lately I've been looking into Plato's import for deep ecology and environmental philosophy. (Dewey has alot to say about Plato and environmental philosophy or nature ontologies, as do others - e.g. Peirce, Schelling, Whitehead.) Most especially I have been looking at Schelling's commentary on the Timaeus with an eye toward thinking about Greek organic naturalisms.
THIS book is also helpful on the subject (another resource on how ancient philosophy might contribute to modern ecological theory), as is THIS IEP article on Plato's organicism. There is some mention of Whitehead in it, fittingly.
Thanks to Matt / Footnotes to Plato blog for the Schelling's commentary on the Timaeus piece (from 1794). That's definitely playing into my current research.