Rock ferns

[ruweiss]

....and some more from the garden at our house:

[TheOnionMan]

Rudi, some beautiful ferns shown.  Many of your images are generically named and do not indicate what fern genera/species they are; can you let us know which ones they are so that we can seek out these beauties.

[kindredspiritkevin]

Brilliant fern display.

[ruweiss]

Rudi, some beautiful ferns shown.  Many of your images are generically named and do not indicate what fern genera/species they are; can you let us know which ones they are so that we can seek out these beauties.

Mark, thanks for your question, 023 is Asplenium trichomanes, 001 and 022 are forms of Phyllitis scolopendrium.

[Hoy]

Any comments on this sporeling I found?  Asplenium septentrionale certainly is one of the parents and the other maybe is A. trichomanes. Both grow near by. However, the cross isn't supposed to look like this!

[annew]

Hello Hoy, it is an exciting find! It does look like the pictures of septentrionale x trichomanes in The Ferns of Britain and Ireland by C.N. Page.

[gote]

It certainly looks like the hybrid. It is uncommon since the parents do not often grow in the same place presumably because of different pH requirements. Where they do it is not too rare
Göte 

[Hoy]

Thanks both!

Anne, I don't have that book but searching the Net gave some similar looking examples. However the drawings in Norwegian floras are different.

Göte, I have never seen it before although both parents are very common where I spend much time in summer. (But I am not down on my knees all the time )

[gote]

There used to be (I have not been there since the sixties) a site near Trosa where the hybrid was surprisingly frequent. I have not seen it anywhere else but septentrionale is rare in my area. Someone told me about a find of ruta-muraria near here. I could not find it and confirm but since ruta-muraria is too tender to grow naturally here I suspect that this also was the hybrid.
Göte
 

[Ed Alverson]

I enjoy rock ferns because they break the fern stereotype - how can these ferns grow in such hot, dry habitats? We have a great place on the edge of town to see many rock ferns in their natural habitats.  By climbing up to the top of this rocky butte, not only does one enjoy a great view, but there are great clumps of the lace fern, Cheilanthes gracillima, to enjoy.

[Ed Alverson]

Mixed in with the Cheilanthes are several other genera that belong to the Pteridaceae family, which hosts the greatest concentration of rock ferns.  Aspidotis is a small genus with only 3 species in western North America; A. densa has a common name of "Indian's dream", though I have no idea where this name came from. Pentagramma is also a small group of western NA species that were formerly included in Pityrogramma, they are known as goldback ferns due to the gold-colored waxy coating on the underside of the fronds.  Cryptogramma acrostichoides is related (though not closely) to European C. crispa, it is much more drought tolerant and has evergreen sterile fronds.  All of these are cold hardy and also drought tolerant, by late summer the fronds will be curled up due to summer drought.

[Ed Alverson]

Mixed in with the rock ferns already mentioned is the western version of the widespread species Cystopteris fragilis; it emerges in early spring but releases spores and goes dormant by early summer, this is its way of escaping drought.  Note that there are three other species of rock ferns growing with Cystopteris in this photo! Woodsia scopulina also grows here but I was not able to find it on this visit; it is not common at this site and is actually most easily seen later in summer after the similar-looking Cystopteris fragilis goes dormant. Polypodium glycyrriza in a west coast representative of the Polypodium vulgare complex; it is a winter-green species that emerges in the fall, releases spores in winter, and then goes dormant in the spring as summer drought approaches.  It is not at its best in May!

[Ed Alverson]

A couple of larger ferns can be found here that are also very drought tolerant.  Polystichum imbricans is a once-pinnate species that is basically a xerophytic form of Polystichum munitum, a common forest species.  Its venetian-blind like pinnae are very dramatic. Dryopteris arguta is an evergreen species of rocky dry shade, here growing under a clump of stunted oaks.  Its closes relative is the eastern North American species Dryopteris marginalis. Finally, a "fern ally", Selaginella wallacei, grows on moss mats on rocks, related to Lycopodium, these "spike-mosses" are now considered to be only very distant relatives of ferns, but they are still spore-bearing vascular plants. 

[Olga Bondareva]

Ed, thank you very much for beautiful images of rare species!

[annew]

Fantastic to see tese in the wild, Ed, many thanks. Polystichum imbricans - gorgeous!