This is P.tenuifolia ssp.lithophile purchased in 2012. Very slow to increase. Note the leaves are more finely cut than a regular fern leaf. I will try to take a better pic tomorrow if we have more sun.
I have mentioned previously but, to repeat, any pictures which I post are completely free to anyone wishing to use them for personal use or catalog. I have no personal attachment to them and seldom keep them longer than the next season.