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/… Many hundreds of similar examples could be cited-- various species of Primula, Silene, Asclepias, Campanula, Rudbeckia, many umbellifers, dandelions, parsnips, etc. In practical terms, including such plants within the scope of "geophyte" renders the term almost meaningless. Dylan Hannon > >