Put this title in Google Scholar for this paper that studied Xerophyllum tenax and Chimaphila umbellata (prince's pine). Belowground morphology and population dynamics of two forest understory herbs of contrasting growth forms. utoronto.scholaris.ca/server/api/c...
I'll check this out. One of the authors was a professor in my dept. (botany) at OSU.
Bear grass plants can be very old. One has been estimated at 90 years old!
Wow, that's great to know! I have seen many well established stands of them in the Oregon Cascades and they are often in fairly undisturbed areas, so I've wondered about their longevity. They are so beautiful in flower!