Creosote gall - home to larvae of the a midge fly. Smoked by the Seri ppl like tobacco. "Adult female midges oviposits (inserts eggs) into the part of the plant her species prefers, then adds a fungal spore. The fungus induces the plant to produce the gall, and the fungus grows inside the gall, lining the inside of the egg chamber. The egg eventually hatches, and the larva feeds on the fungus." Pictures of how it works here: http://www.birdandhike.com/Wildlife/Invert/Ph_Arthropoda/SubP_Hexapoda/Cl_Insecta/Diptera/Midge/Cecidomyiidae/Asphon_aur/_Asp_aur.htm