In the shadow of the Tree
In which the number of Vertu’s passengers increases again.
“Salmo’s Fire” is St. Elmo’s Fire, a weather phenomenon related to lightning; Yulie’s description of what it is and how it happens covers the basics. He doesn’t mention, since it’s outside his experience, but on Earth it’s particularly associated with the masts of ships, which is why it’s named after the patron saint of sailors.
This, however, the greenish glow enveloping Vertu’s taxi — this is not St. Elmo’s Fire. You don’t get St. Elmo’s fire enveloping an entire vessel; as Yulie says, it happens at the tips and points of things, and that’s a necessary condition of its formation. Also, real St. Elmo’s Fire is never green. Given the green, I suspect the Tree of being up to something. Perhaps it’s offering the kittens what welcome and protection it can at the remaining distance.