I wondered some of the same stuff about Black Palm. As KellyG mentioned, the wood is used for entire bows, so I figured it must be worth a shot. A buddy had some smaller pieces of it, so we ended up doing some tests, because like you mentioned, that "grain" looked a bit strange...
We noted a few things while testing it. One was it soaked up super glue like you wouldn't believe. Another was it seemed really strong. The pieces that broke under a large amount of stress cracked or broke running the length of the grain. We had a heck of a time trying to get it to break perpendicular to the grain.
I ended up buying a REALLY dense (not because of high moisture content) board of Black Palm from an exotic wood place. I plan on using it for riser material and tip overlays. The piece I got seems to be a lot better than the scrap that we tested on-I'd imagine it will hold up very well. Just my $.02
.
Jeremy