Friday, June 19, 2015

Dryopteris celsa at Panther Creek

On the way back to Gainesville from western Virginia (I drove), I stopped to visit an old friend and colleague, Tom Goforth of Crowdog Native Ferns and Gardens in Pickens, South Carolina. I spent a few lovely days with Tom to catch up, and we visited one of my favorite sites from my PhD studies, a place Tom has known of and visited for years: Panther Creek in northeastern Georgia. The highlight of this spot, for me, is Dryopteris celsa. This was the first place I ever saw this fern, one of the allopolyploids in the North American Dryopteris complex. Getting to the populations of D. celsa at this site involves wading across a rive and choosing the right valley to walk up on the other side, amid dense forest and a thriving understory. It's a really beautiful place:


However, we came across an unfortunate surprise once we found the valley with D. celsa. The population of this fern, which had been thriving the last time I visited four or so years ago, has been drastically reduced. We saw very many fewer adult individuals of D. celsa than last time, and almost no evidence of new recruitment in the form of young sporophytes. Tom and I are both at a loss as to what may have caused this; climate change and wild hogs seem like the two most likely suspects. The remaining D. celsa individuals are still lush and beautiful, but I worry now that the population may be on its way out.






Monday, June 15, 2015

Virginia ferns, part III: Vittaria appalachiana

The highlight of our trip to Virginia (posts I and II) was finding Vittaria appalachiana in a perfect sandstone habitat at the end of a trail near Mountain Lake Biological Station. The trail was called Bear Cliffs trail, and it terminates in some craggy shallow gorges that are full of ferns and other vegetation. Our group included several researchers who have worked extensively on fern gametophytes and several gametophyte-only species - these are ferns that never make sporophytes (the big, green, leafy things that we think of when we think about ferns). A classic example of this type of life history in ferns is Vittaria appalachiana, also known as the Appalachian gametophyte, which occurs in sheltered sandstone rockhouses throughout the Appalachian mountains and plateau region. After a thorough hunt, we were able to turn up some V. appalachiana tucked back in one of the sandstone shelters!

Typical sheltered habitat for V. appalachiana
The dark crevices are where these ferns like to live
Joel Nitta, a grad student at Harvard, after gametophytes!
The product of a successful search - a tweezer-ful of Appalachian gametophytes



Wednesday, June 10, 2015

Virginia ferns, part II: Dryopteris

Continuing the posts about our trip to Virginia with some photos of Dryopteris, the wood ferns! Most of these are of D. campyloptera, the mountain woodfern. It is an allopolyploid of D. expansa and D. intermedia, and has an interesting distribution, restricted to higher elevations and/or more northern latitudes in the eastern U.S.


D. campyloptera
Typical D. campyloptera habitat 
D. campyloptera
More foggy mountain-top habitat!
D. marginalis
D. marginalis
D. marginalis

Monday, June 8, 2015

Virginia ferns, part I: Asplenium

Last week there was a once-in-a-decade fern conference held at the Smithsonian Institution in Washington, D.C. Every ten years or so the fern community gets together to hold such a meeting, and people come from around the world to hear about what's new and exciting in fern biology. Next Generation Pteridology was the name of this meeting and it was a great success and a lot of fun. After the conference, I headed to the field with some old fern friends to do a bit of exploring in western Virginia. We were particularly interested in finding populations of Asplenium and Dryopteris species, and we were successful. I'll post the pictures of Dryopteris in part II, but here are three species of Aspleniums and a few other botanical highlights.

Asplenium platyneuron
Asplenium trichomanes
Two Aspleniums
Asplenium rhizophyllum, the walking fern
Athyrium filix-femina, lady fern
Pellaea glabra
Some gratuitous lichens! 


Monday, May 25, 2015

More Pine Rocklands

I've written before about a project on the endangered Pine Rocklands ecosystem of South Florida that I'm working on with my colleague Ben Baiser at UF and our master's student Lauren. We just went down to the Miami area for another field trip and it was great to see this habitat at another time of year - the previous trip had occurred in the fall. We managed to see a few more fern species that we had not seen on the last trip, as well as a few that are starting to become regulars.

Pleopeltis polypodioides
Vittaria lineata
Acrostichum danaeifolium
Acrostichum danaeifolium 
Anemia adiantifolia
Psilotum nudum
Psilotum nudum
Palm tree with Nephrolepis

Friday, February 27, 2015

Ferns in the news: weird sex


Botanists say this plant is the fern equivalent of a human-lemur love child.
Photo by Harry Roskam
It's always a good day when ferns make the news, so the last few weeks have been pretty great! Carl Rothfels and colleagues have determined that two ferns alive today, but whose ancestors diverged from one another around 60 million years ago, have hybridized to form a new (although sterile) species. The new species is a hybrid between two different genera, Cystopteris and Gymnocarpium, and its name is Cystocarpium roskamianum. Intergeneric hybrids are very rare, because it becomes more and more difficult to be interfertile the more diverged two organisms are from one another. We often consider species to be units that are distinct from one another reproductively (although this is frequently untrue, particularly in plants), and genera are implicitly assumed to be even more so. There are four other known intergeneric hybrids in ferns, including Dryostichum singulare, a hybrid between Dryopteris goldiana and Polystichum lonchitis, but none involve parental genera as anciently diverged as Cystocarpium's. The authors use the analogy that this would be like a human and a lemur mating and producing offspring – the genetic distances involved are similar!

The story has been covered by a number of news outlets. Links are below, and I'm pleased to add that I was contacted for a comment for the NPR piece, which I very happily gave. 

Friday, January 30, 2015

OTS Fern Course

I just got back from spending three weeks in Costa Rica, attending a special course on Tropical Ferns and Lycophytes from the Organization for Tropical Studies (OTS). This course was first offered in the 1960s, and not again until 2008. I went on the 2008 course as a student, and returned this time as a visiting faculty member. We spent a few days in San Jose and then a week each at two OTS field stations, Las Cruces in the southern part of the country, and La Selva north of San Jose in lowland rainforest.

Las Cruces is particularly fun for the bird life, and many beautiful species show up for the daily offering of bananas outside the dining hall:

Blue-crowned motmot
Male green honeycreeper
Silver-throated tanager
Speckled tanager
And now just a few of the dozens (possibly hundreds) of ferns we saw over the course of three weeks...
Tiny sporophytes of Asplenium holophlebium
Hymenophyllum 
Ophioglossum
Hymenophyllum sporangia with green spores apparent 

Two members of Gleicheniaceae, Sticherus (darker green) and Gleicheniella (lighter green)
Gleicheniella
An tree tipup with incredibly dense fern gametophytes