In Canto 13, Vigil and the Pilgrim enter the second ring of the seventh circle of Hell.  The souls being punished here are the only ones so far that are represented as a manifestation of something other than a human form.  Even though none of the souls the Pilgrim has seen on his journey have been attached to their former bodies, they have always appeared as though they had bodies.  Many times these souls even look as they did in life, since the Pilgrim tells us on multiple occasions that he recognizes them (as in canto 12, line 123 for example).  There have been a few occasions where the souls are unrecognizable: the instance in canto 6 where the Pilgrim encounters Ciacco who asks if  he can recognize him, the Pilgrim responds “”The aguish that you have perhaps drives you from my memory, so that it does not seem I have ever seen you”” (lines 43-45); the Pilgrim’s response shows the reader that in this case (gluttony) the suffering has altered the appearance of the soul so that it no longer looks like the body and can not be recognized from life on Earth to life in Hell.  Even the cowards in canto 3, who are unworthy of remembrance even, are recognizable (canto 3, lines58-60).

So it is a great shock for the Pilgrim when he encounters the souls in canto 13, who do not appear in even a remotely human form.  When they arrive in this circle, the Pilgrim can hear the sounds of suffering all around him but can not make out where they are coming from–the voices are disembodied, quite literally, although this may make the reader realize that all the voices (including the voice of Virgil, who represents the voice of truth and reason throughout the poem) are disembodied.  The eerie feelings surrounding the Pilgrim at the beginning of this canto are a reminder of his mortality and the fact that he should not be in this world that belongs only to the dead.  The reader is just as confused as the Pilgrim here, as we find out the truth through his actions just as he does–since we are human and we are alive we feel the same uneasiness at the disconnect of our souls and our bodies.  The souls in this circle are manifested as bushes and plants–a fitting punishment since they did not respect their bodies while they were alive.  In death, the other inhabitants of Hell have been granted an illusion of a body, a connection to their visual representation on Earth.  Though it is not much consolation, these souls who look like their bodies are able to maintain more of their identity in death since the physical appearance remains at least similar (the soul the Pilgrim speaks with never tells us his name, as though he no longer has a right to his identity associated with it just as he no longer has the right to the identity associated with his body).

It is important too that the souls are plants and not animals.  The souls here are being punished for violence towards themselves–they used their free will, their agency, and their bodies against themselves; so it is fitting that as punishment they take the form of something with  no agency–no hands to hurt themselves with.  In life they were confronted with pain or problems and rather they chose to destroy themselves in order to escape what they feared on Earth.  Now they have no ability to stop the physical pain they are being caused by the Harpies (as they have no defense system) and no ability to escape the pain as they did in life (since they are without agency and limbs).

The soul the Pilgrim speaks with explains that even after the last judgement, when all the other sinners will have their bodies reconnected with their souls, the souls here will have the cruel privilege of their bodies being returned to the plant which now houses their souls.  Since the last judgement is the perfection of their punishment, these sinners will be forced to see the bodies they destroyed, disrespected, and took away from themselves and be unable to return  to them.