People often use 'marrow stromal cells' or 'mesenchymal stem cells' interchangeably as scientific terms (but of course, there is debate) that refer to adherent colony-forming multipotent cells. We use 'bone marrow stem cells' as a non-scientific term that includes MSCs as well as hematopoietic stem cells and endothelial stem cells.

>Is there any reason you can't get this from whole blood?

The blood harvest process uses a machine, takes a few hours, and requires the prior administration of a protein that stimulates stem cell proliferation and release into the blood. It is preferable for some procedures, but for those reasons, not for ours.