That may just be the reporter simplifying to match the newspaper’s target audience.

There are different types of stem cell, true. My guess is that they’re talking about hematopoietic stem cells (hence bone marrow), and those are also found in the blood stream and collectible through periphery donation. The first link actually talks about PBSC donation in terms of bone marrow transplants in the opening paragraph.

We’ll find out for sure when they publish the journal next week :)