Costa Rica & Panama 2017
I started off this trip with Dave Barrington's Tropical Plant Systematics field course in Costa Rica, which has become a staple of the University of Vermont's Plant Biology Department, running every two years for the course of the last four decades. I've been involved in the course for the past three trips, and it is a blast. The trip focuses on the country's Pacific slope, and covers plants from the paramos of Cerro de la Muerte to the perpetually wet lowland forests of the Osa Peninsula. The course is primarily focused on flowering plants, but the fern diversity is too rich to ignore!
On this trip, I was finishing up my PhD work, and so used the opportunity to collect a lot of Phlegmariurus, the lycophyte genus that has been the focus of my dissertation. Though the genus is much more diverse in the northern Andes, there are a lot of interesting species here, and I have been able to spend enough time with them to notice some new things, including lots of potential hybridization, which has gone practically unreported in the genus to date. It seems that hybridization is much more common in the terrestrial species than in the epiphytic ones, probably because of the tendency of the former group to grow in mixed-species communities. Detecting hybrids in this group is challenging because it appears that interspecific hybrids undergo appropriate pairing during meiosis and produce normal-looking spores (their viability remains unknown). Further, it is hard to pick out hybrids in the genus because, well, the species tend to look pretty similar. On this trip, I collected three likely hybrids: Phlegmariurus talamancanus × Phlegmariurus attenuatus, Phlegmariurus hoffmannii × Phlegmariurus reflexus, and Phlegmariurus brevifolius × Phlegmariurus crassus. Sequence data backs up the hypothesized hybridization schemes I came up with in the field - more on that soon!
Unfortunately, while we were in the Osa Peninsula, I got quite sick with a flare-up of malaria that I contracted several years back. While I recuperated in San Jose, the rest of the course continued to Guanacaste Province and undoubtedly saw lots more great plants. Afterwards, I continued down the Caribbean coast and crossed into Panama. Though it was well-collected a century ago, much of Panama remains understudied with respect to fern and lycophyte diversity, and there are a lot of narrowly distributed species in both the far eastern and western portions of the country. On this trip, my plan was to scale Volcán Barú, Panama's tallest peak and home to a near-endemic species of Phlegmariurus. I had tried to summit two years prior with my friend Christian López, but we were unable to enter the park due to volcanic activity. This attempt also would prove ill-fated; the day before I was to start my hike, foggy weather settled in, and the park was closed again.
Instead, I re-traced the steps of famed early 20th century fern collectors Alice Cornman, Ellsworth Killip, and William Maxon, heading up a small trail along the Rio Caldera that skirts the northwest flank of Volcán Barú. I had visited the trail on my previous trip, but only made it a short distance. Better prepared this time, I was able to push much deeper into the forest and found some great fern and lycophytes. Maxon described several species based on material collected from 'Holcomb's trail' - the remnants of which I was hiking on - and I was able to find some of the taxa still there, including Eupodium pittieri and Phlegmariurus foliaceus, Based on E.P. Killip's writings in "Fern-hunting in Panama" (American Fern Journal 9(1), 1919) the trail continued tens of kilometers to the north, eventually crossing the Talamanca Mountains before petering out in the dense rainforest of the Atlantic lowlands. Maybe on the next trip.