Well it's not much, but given the difficulty of getting the thing even a half inch tall took a mighty effort :-) so anyway, my horticultural contribution to the season, except for the grinches out there :-) who might want to wait a few months before reading this thread :-)
Frankincense comes from the dried sap of this tree, Boswellia sacra. They only grow in a very few, very arid regions where there's lots of dew in the morning but very little water and no frost. Oh, and the soil has to be a degraded limestone, and it must be boiling hot in the summer. So that's why the stuff has been so insanely valuable throughout history, as only, like, the Sultan of Oman gets the best for his personal stash rare. And germination is really bad; only one out of the 5 seeds I bought came up.
It's used for incense of course, and there are medical uses. You wound the tree occasionally to harvest the dried sap, but only after the plant is really old. Anyway, here's what it looks like: