[Caduceus nods and ventures over to the tree, pausing in front of it to rest his hand briefly against the cold bark.]

...Hey there. Hope you don't mind, I'm gonna give you a few neighbours at your roots. Nothing feisty, they should get along with you just fine. Treat them well, would you?

[The tree's branches rustle subtly; hard to say if it responded, or if it's just due to the wind. Caduceus seems satisfied anyway, gathering up a handful of fallen leaves and a dead branch at its base. He presses his hand against both, murmuring under his breath, and after a little bit of waiting, several fungal stems emerge, the beginning of a mushroom cluster. It's just the start, and it'll take a few minutes to really grow in earnest, but Caduceus straightens up, smiling back at Rue.]

Oh, that's a really good species. You got lucky there.