The current icon for branches, among your favorites, doesn't necessarily connect with me ... I think the solitary star makes branches appear more 'favoritey' than the actual favorites, which causes a visual break: my eyes are trained to look for folder-like icons when looking for, well, folded item collections. If that makes sense?
Ideally, I wish to be able to pick my own branch icons. If anything at all, I'm casting my vote for a more general, folder-like, or, folded-like, icon: perhaps a folder with a star, or sumpn like that. Granted, it's possible that such new icon might also inherit some visual discrepancies with your OS' folder icons, but that's another story ... which even makes me think this whole thing could be remedied by simply grabbing current sys folders and tacking the star on top, and simply call it a day; I don't know. To complicate matters a bit further (why not), the opportunity just presented itself, to maybe take the simpler router and enable users to set branch text in bold. Maybe that's enough to distinguish them as containers with more favorites in them? Now I'll shut up and leave some air for contemplation.