From what I can make out using google the tubers are root tubers like potatoes but I cannot find a picture. Dylans tap root scenario is not typical of the solanacea which I know and which readily produce adventitious roots, - in my opinion better to go with 'anchor' and 'fibrous' roots as a basis for root systems. I recall my father redrawing diagrams and having school technicians make accurate models when he taught. I have a feeling that the tubers may be dependent on night length to form?? I have read that this is so in Dahlia which is probably a very different type of tuber - Peter (UK) On Mon, Dec 30, 2013 at 1:59 AM, Hannon <othonna@gmail.com> wrote: > I recall seeing the rootstock of Datura wrightii in years past. My > impression agrees with this site, which gives Datura as an example of a > taproot: > > > http://transtutors.com/homework-help/biology/… > >