As he clearly implies, the full picture of the roots and branches of a word can be an "intertwining tangle". A particular word may be reached via several different transdeletions (or transadditions), and the resulting diagram can be confusing, with many lines crossing each other, and there being no clear indication of the structure.
"Roots and Branches: A Simplified Diagram,"
Word Ways: Vol. 36
, Article 8.
Available at: http://digitalcommons.butler.edu/wordways/vol36/iss1/8