Hi, I read this in the 1980s, it was a paperback, and there was a group of explorers or an expedition on this deadly planet. The explorers and guide are taken hostage and forced across the planet, for some reason I can't remember. Several of the terrorists are killed by the planet, with the guide not giving information, or giving wrong information, etc. I specifically remember one of the terrorists is a woman who puts a flower in her hair. The guide notices but says nothing, and a few days later she falls over dead, the flower having grown into her brain and eating it. I thought this was a Commonwealth series book by Foster as one of the explorers was a Thranx who broke a leg or had a leg bitten off, and the guide was from another commonwealth book, however nothing that I've seen matches. I could have easily missed something, though. Any help would be greatly appreciated!