wood species?

My older son works for a tank manufacturer that builds tanks for fertilizer sprayers, fire trucks, etc. They receive large bunks of stainless steel or aluminum and in between the bunks are large "stacker" boards that normally measure around 3"x4". The boards are rough and sometimes weathered but after running the ones that are straight and not too split out through my planer I come up with some really nice free wood to use for my projects. I've only been doing some woodworking for about two years and have built some furniture from pallet wood and these pieces that I plane work great for legs for tables or I can rip them down to use for frames for different items. Most of what he can get is oak but once in a while I'll come across a piece of poplar or cherry. This piece that I'm posting a picture of looks neat with the very dark grain but I'm not sure what type of wood it is and am hoping someone here can tell me. I would add that my son is able to get large loads of these free boards of which probably 80% are either too bowed or split to use for woodworking but I chop those up with my chainsaw and use them in my large wood burning stove in my shop. Can't beat free firewood.