Pioneer Valley Fern Society

2022-2023 Winter Ferns

#7 Purple-stem Cliffbrake

We have gone back into winter mode for a bit, so I can continue with our Winter Ferns series!

The Purple-stem Cliffbrake (Pellaea atropurpurea) is a lovely, delicate evergreen fern that grows on calcareous cliff faces, with their roots in the rock crevices. They are uncommon in MA & VT, and extremely rare in NH & RI. Although there are 15 species of Cliffbrake in the US, most are in the arid Southwest. They extend from Guatemala to New England. This is the only species found in MA. The species name comes from the greek word atropurpureus, for the dark purple stem.

We were recently fortunate enough to receive some wonderful fern books from the library of Paul Penfield Jr. One that I really enjoy reading is "How to Know the Ferns" by Frances Theodora Parsons, published in 1899. She describes the typical location of this fern accurately as "The Purple Cliff Brake is one of the plants that rejoice in the un-get-at-able and perilous situations." She goes on to say "Although its range is wider than many ferns, this choice of inconvenient localities, joined to the fact that it is not a common plant, renders it likely that unless you pay it the compliment of a special expedition in its honor you willl never add it to the list of your fern acquaintances." We were fortunate enough to have two friends who independently discovered some of these wonderful ferns in very inconvenient locations at Mt Toby and the Pocumtuck Range a few years ago. Randy also found some at another very difficult place in Hampshire County. I imagine the Purple-stem Cliffbrakes have survived in good part because of their difficult to access locations.

If you happen to visit the right habitat, it is a distinctive fern, not similar to any others growing there. The leaves are a lovely greenish to bluish grey, with dark purple to black stems (rachis & stipe).The sterile fronds have rounded leaflets, while the fertile fronds have longer stems and leaflets, with the leaflet margins rolled over the sori on the underside (called a false indusium). In this photo you can see the two different shaped leaves, but the sori are on the underside and not visible. It is nice to know that even through the winter we have some "fern acquaintances" still out there for us to enjoy visiting.