I've put that neotropical plant-site on my taskbar; very useful!
In the mean while the 'Flora do Brasil' is back on line:
8 species are recorded for the Rio de Janeiro state:
- Guatteria australis
- Guatteria campestris
- Guatteria candolleana
- Guatteria ferruginea
- Guatteria latifolia
- Guatteria pohliana
- Guatteria sellowiana !
- Guatteria villosissima
I feel that Guatteria sellowiana is indeed the best match!