I took these out in the garden today. This is the first time I had these two species in flower at the same time, though they are different areas. Usually P. acaule is all done flowering by the time P. yampaensis gets started. I guess this shoots down my theory about why they don't seem to intergrade.
The later is over twice the leaf size but the flowers are about the same size.
![](/sites/default/files/styles/medium/public/forum-images/20150424_164721.jpg?itok=f7z2VwE5)
![](/sites/default/files/styles/medium/public/forum-images/20150424_164536.jpg?itok=10u4QrQE)
![](/sites/default/files/styles/medium/public/forum-images/20150424_164448.jpg?itok=8EHPDcLQ)