Definitely Xanthosoma. Myriam, your link to the Flora comes up blank for me, but when I do a search for Xanthosoma, leaving all other fields blank, there are many more than 5 results. Goncalves lists the following
cultivated Xanthosoma as native to Brazil.
X. appendiculatum. Easy to ID because it has a little leafy appendage on the underside.
X. atrovirens (not native but at the Sitio Roberto Burle Marx
X. blandum
X. brasiliense (not yours, leaves almost tripartite, lobes almost separate or separate).
X. riedelianum (not yours, leaves constricted at base of lobes)
X. taioba (possible)
Xanthosoma maximiliani is also a Brazil native. I find it spelled Xanthosoma maximilianii as well as Xanthosoma maximilianum. Same author, publication and date are cited. I guess I should get those into our DB.
You can find good, reliable photos of Xanthosoma here:
http://www.aroidpictures.fr/GE...