Dryopteris ludoviciana

One of the most exciting parts of my trip to the Carolinas was finding Dryopteris ludoviciana, the Southern Shield Fern. Dryopteris is the genus I work on, and there are 13 species in North America; D. ludoviciana was the last one I hadn't yet seen in the field, so it was a total thrill to find it! We had information from some old herbarium vouchers (circa 1939) that it could be found with one of its hybrid offspring, D. celsa, in a swampy area next to a creek in northeastern South Carolina. After hacking through the woods and underbrush for an hour, we finally stumbled across both of the ferns growing happily together at the base of a cypress tree. 

This is the open-water part of this lovely swamp:

Here are several of the ferns growing together:

D. ludoviciana is one of the putative parents of D. celsa, which is a hybrid; the other parent is D. goldiana. They all look vaguely similar, but the first two (which we found here) in particular share a lot of features. Side by side, however, they're clearly different. In the image below, D. celsa is on the left and D. ludoviciana is on the right. D. celsa has larger pinnae overall, and there isn't much difference between the sterile pinnae (towards the bottom of the frond) and the fertile pinnae (the two or three topmost in the picture). D. ludoviciana has smaller pinnae overall, compared to D. celsa, but there's also a definite difference between the sterile and fertile pinnae. D. ludoviciana's upper, fertile pinnae are contracted and very reduced (see photo just above, right). 

South Carolina Coastal Plain

For my first outing of this field season, I spent a week exploring the Carolinas and part of Georgia with native fern expert Tom Goforth of Crowdog Native Ferns & Gardens. We had a fantastic time, and spent two particularly interesting days exploring the Coastal Plain of South Carolina. One of the most beautiful places we visited was the Lynchburg Savanna Heritage Preserve. 

This wet longleaf pine savanna was stunning, populated with numerous wildflowers and several species of ferns. It was interesting throughout my week in the south to find several species of ferns that were growing in several, very different environments around the area. At this savanna there were Woodwardia virginica (Virginia Chain Fern), Osmunda regalis (Royal Fern), and the ubiquitous Pteridium aqulinum (Bracken), all of which I've seen growing in dark, shady environments as well as out in the open, as they were here.

The ferns were very cool here, but even I have to admit that the real show-stoppers were the wildflowers (click to see larger pictures):

First ferns

Greetings! A week ago I went on my first field trip of the season, to a natural area called Abraham's Woods in south-central Wisconsin. The forest floor was covered with spring ephemerals, like the Dicentra cucullaria visible in the image above. In addition to the flowering plants, we found fiddleheads of various fern species that were just emerging. Very exciting to find the first ferns of the season!

This is lady fern, Athyrium filix-femina.

There is a part of Abraham's Woods that is very close to the edge of the glaciation zone in southern Wisconsin, and on the leeward side of a hill/moraine is some very thick, dark, mesic soil. This is a perfect spot for Dryopteris goldiana, which makes the giant fiddleheads pictured above, with my fingers for scale. 

 

And some ferns were even unfurling, like this Cystopteris fragilis.

Evergreen Ferns

Now that the snow has melted and one can venture outside again, a feature of the late fall/early spring forest landscape you might notice is a surprising amount of green. This is due in part to evergreen ferns. These are a select set of species that drop their fronds to the ground in late fall, but keep them attached to the base of the plant, where they remain green through the winter months. There's actually a nifty mechanism by which this occurs: there is a joint right at the base of the frond that weakens at the appropriate time, so that the frond falls where it's been standing.

There are various hypotheses in the fern community about why these species do this. The consensus seems to be that having green, living fronds may allow them to jump-start photosynthesis in the spring when the snow melts and sunlight becomes available. Based on the ferns in the forest at my parents' house (where the above photos were taken), that seems like a reasonable theory. There are several species in the North American fern flora that do this, including Polystichum acrostichoides (middle photo, above; its common name, Christmas fern, reflects the fact that is a dark green color through late December) and Dryopteris intermedia (lower photo, above).

I should mention that these ferns aren't truly evergreen, in the sense that conifers are. Conifers hold their leaves through multiple growing seasons (although they do replace them eventually, usually once every 3-5 years). These ferns keep their fronds only until the next spring; when the fiddleheads start to emerge they will begin to senesce and disappear into the leaf litter.

Interrupted Fern

The snow is starting to melt in Wisconsin, so I'm looking forward to the arrival of spring and a return to regular blog posting. I saw this posted on a friend's Facebook profile the other day and wanted to share it: an amusing comic about Interrupted Fern (a.k.a. Osmunda claytoniana). Of course, it really gets its name from the fertile pinnae that "interrupt" the sterile green pinnae along the rachis (see below). But the comic (drawn by Rosemary Mosco of birdandmoon) is a good interpretation, too. 

Darwin and Botany

2009 is a big year for evolutionary biology. In a few weeks, on February 12, we will celebrate Charles Darwin's 200th birthday, and later this year marks the 150th anniversary of publication of the Origin of Species (such a smart man, I'm sure he planned it that way!). In honor of this fascinating scientist and person, I thought I would provide the best links for reading Darwin online, and mention the intersection of botany with his thinking and works.

First off, let me comment that it's not going too far to say I love Darwin; he is a fascinating person, both as a scientist and a man. His writings are an incredible treat to read, accessible and full of tremendous insight into the natural world. The first book of his that I read was the Voyage of the Beagle, and if you haven't read it, I recommend you race out immediately and buy a copy. It is an easy, fantastic, exciting, thought-provoking read. If you aren't inclined to buy, you'll enjoy the first of these links:

• The Complete Works of Charles Darwin online  This treasure-trove is exactly what it claims to be: all of Darwin's writings. All of them. That means all of his major books, including the Origin, plus his numerous papers, many of which are botanical, and page-by-page images of his many notebooks and diaries.
• The Darwin Correspondence Project   The DCP's goal is to publish all of the letters Darwin sent and received and that are extant (i.e. weren't lost or thrown out). The Correspondence is voluminous; Darwin had close to 2000 correspondents and wrote up to 500 letters a year in the years following 1859. This site has most of the letters that have been transcribed, as well as letter sets on various subjects, and guides to reading the letters of different people. It is fascinating to read his correspondence with critics and with his supporters as he fleshed out his theories.

I cannot say enough about the delight you will get from reading Darwin. He was a joyful observer of the natural world, and his enthusiasm is clear in his writings. Also clear are his modesty and desire to be understood by his reader. 

I admit that I (like most scientists) haven't read many of Darwin's less-famous papers and books, but a good many of them are on botanical subjects. Darwin suffered from illness and infirmity for most of his later life, and he took refuge in his experiments and wanderings at Down House, which he vastly preferred to the scientific fray in London. He relied on correspondence with his botanical friends for a huge amount of information in the Origin, particularly about biogeography and the immutability of species, and in his later years he increasingly turned to botanical experimentation and direct observation himself. He published books on the following botanical subjects: orchid fertilization, climbing plants, insectivorous plants, cross and self fertilization, flower forms, and plant movement, as well as dozens of papers on everything from variegated leaves to whether sea water kills seeds. All of these are available at the Complete Works of Darwin website listed above, and it is great fun to explore his writings and see the world through his eyes!

Top 100 Botany Blogs

Happy February! Online college blog has assembled a list of what they consider to be the top 100 botany and plant-related blogs: Top 100 Botany Blogs. I'm very pleased and honored that No Seeds was included! We're down at #91, in the Plant Specific section. Go check out some of the others, all are wonderful and fascinating!