Re: R. spithamea
The reason the two statements on prickles seem contradictory is that both are only partly correct. Some branches have no or very few prickles. Others many straight prickles. My observation (this rose grows among rocks in the hills outside my town, and comes back every year without fires) is that the lower and older branches of this ground hugging rose rarely exhibit prickles, while the smaller, newer branches (twigs, actually) are usually quite full of straight prickles.