Davana (Artemisia pallens)
Davana is an odd bird. There aren't many choices for the letter "D" though, so davana it will be. Douglas fir feels kind of like cheating, and deertongue is impossible to find (no deer were harmed, it comes from a plant). I'm not sure if I've sniffed dill essential oil (the seed or weed), but I worry it would remind me too much of pickles.
Davana has a strong odor, described as fruity, herbal, wine-like, sweet. Arctander describes it as "...sharp, penetrating, bitter-green, foliage-like and powerfully herbaceous with a sweet-balsamic, tenacious undertone," in Perfume and Flavor Materials of Natural Origin. It is usually steam distilled from the aerial parts of the plant (as opposed to the roots). It was a fairly new material at that time, and he doesn't write much about it.
Arctander recommends using it in a chypre or fougere, partly because those already have dark colors, so the a dark davana oil won't matter. It would be a nice modifier in a chypre, connecting the loamy oakmoss to the sparkling bergamot. I picture the green and sweet aspects blending well into a fougere scent as well.
Other forms of davana you might find include a CO2 extract or perhaps an attar. I have listed a few other artemisia varieties below- please look into safety issues when using any of these (including davana).
Owyhee/White Sagebrush- Artemisia ludoviciana
White wormwood- Artemisia alba
Wormwood- Artemisia absinthium
Sweet Wormwood/Sweet Annie- Artemisia annua
Tarragon/Estragon- Artemisia dracunculus