Wednesday, March 18, 2009

Ozarkian Atrichum

Back in early February, I collected a moss that had to be in the genus Atrichum (Polytrichaceae). It was acrocarpous with lanceolate leaves possessing lamellae (gill-like flaps) along the costa (midrib) and had serrate teeth on the margins. But it was a species that I didn’t recognize. There are two species commonly encountered in the Midwest, A. altecristatum and A. angustatum. Both can be readily identified by field characters. This one didn’t match either. Then last Sunday, I collected another Atrichum that looked different. Needing answers I turned to the Flora of North America volume on acrocarpous mosses. In it, I learned that there are only five species of Atrichum in Missouri and that one of these species is restricted to bald cypress swamps in the Bootheel. At this point I thought to myself “if my summation is correct, I have collections of all four Atrichum known from the Ozarks (of Missouri, at least)”.

Having been intimidated by bryophyte keys many times before, this time I stood steadfast, mustered my patience, gritted my teeth and dove in head first. Three hours later, I emerged victorious; blooded but unbowed. And as with any successful quarrel with a difficult plant group, at the end I asked myself “could it really be that easy?”. Here’s the breakdown:

From left to right: A. crispulum, A. crispum, A. altecristatum, A. angustatum. Note their relative size.

As luck would have it, A. angustatum is not only the most common species in the Ozarks, it is also the easiest to identify. Here is what it looks like in the field.

Identifying A. angustatum comes down to two characters. First, the leaves will be significantly less than 1.0 mm wide. Second, the costa and associated lamellae (basically what would appear to be the midrib of the leaf macroscopically) will account for one quarter or more of the leaf width. Terminology aside, pretty easy stuff. Here is a closer shot of a leaf where you can see the proportionally wide costa.

While all four seem to be acidophiles, you will commonly find A. angustatum in the driest of acidic habitats; cherty acid uplands, margins of igneous glades and sandstone outcrops. Like many mosses, it grows in large colonies on exposed soil such as tip-up mounds, ditch margins and that special little litter free micro-habitat that exists around the perimeter of large tree trunks. For the most part, A. angustatum is the shortest Atrichum in the Ozarks (see line-up photo above).

The second most common species in the Ozarks is A. altecristatum (formerly known as A. undulatum; in part). It is also readily identified by macroscopic field characters. The first thing to notice is that the leaves are strongly undulate (wavy like a lasagna noodle).

Other species have this character, but it is definitely more pronounced in A. altecristatum. The second character is height. As you can see in the line-up photo at the beginning of this post, there is a progression in height. It is taller than A. angustatum, but significantly shorter than A. crispulum and A. crispum. The rule of thumb is that A. altecristatum is one to three centimeters tall and the two taller species are two to six centimeters tall. I know what you’re thinking, “there is that damn overlap that makes this stuff so difficult”. Fear not, most specimens fall toward the extremes. A third character is habitat. Atrichum altecristatum is the weediest of the four species and occurs on areas of bare soil in mesic to dry-mesic forests. While its occurrence in intact native landscapes is well documented, it clearly increases in abundance under certain levels of disturbance; chiefly woods that have been heavily grazed. Perhaps it is the soil compaction coupled with the increase in exposed soil, but an abundance of this species indicates abuse. This is important because the remaining two species demonstrate a high fidelity to intact natural communities. They also occur in wetter habitats.

Atrichum crispulum also has undulate leaves. In fact, even under a microscope they are nearly identical to those of A. altecristatum. However, plant height and habitat easily differentiate the two.

Here is A. crispulum that has been rehydrated on my porch. This particular specimen is close to five centimeters tall; nearly twice the height of the average A. altecristatum. Atrichum crispulum is a species of undisturbed plant communities and is found in moist to wet protected slopes and wet sandy ledges in shady ravines. It has just recently been recognized as occurring in Missouri and is state listed as SU. Any new locations would be good info for the Natural Heritage folks.

The last species to round out the Ozarkian Atrichum experience is A. crispum. It is also found in wet habitat with intact native integrity.

It differs from the previous three species in lacking undulate leaves. In height it resembles A. crispulum, but it is more sparsely foliose.

That’s it! Height, undulations and habitat are all you need to distinguish the Atrichum of the Ozarks. Don’t ask me why the keys are based on the length of single cells and other equally tedious characters. It goes to show that with some field experience, some collecting and the process of elimination, moss identification is not only possible, its kind of fun.

Monday, March 2, 2009

Botany Road Trip: Spring 2008

Every spring I like to take a botanical road trip. Last spring my buddy Brad from Michigan came down and we took a southern tour. Due to a computer malfunction, I was unable to show my slides of the trip at the annual Botany Slide Show Extravaganza this winter. So, being compelled to salvage the usefulness of my slides from the trip, I put together the following.

The trip started right here in Dent County with a visit to Big Glade at Indian Trails State Forest.

Big Glade had received a solid burn earlier in the spring. The tender green tips of summer grasses and sedges were just breaking dormancy and lending a green buzz to the chert strewn dolomite shelves of this spectacular natural area. As it was early yet, few plants were flowering. Here are two fun ones:

Castilleja coccinea (yellow form) is one of my favorites. This hemiparasite is common on glades, but rarely abundant.

This is Silene caroliniana var. wherryi. In Missouri, it is only known from a cluster of counties in the central Ozarks. This variety also has disjunct populations in Ohio, West Virginia, Kentucky, Alabama and North Carolina. It differs from other varieties in lacking glandular pubescence within the inflorescence.

From Big Glade we headed south to a chunk of National Forest near Birch Tree. Our quarry….the state imperiled/globally vulnerable Ozark Wake Robin (Trillium pusillum var. ozarkanum).

We were surprised to find this beauty blooming in profusion along the road ditch. A thunderstorm was riding down our backs, so we didn’t stay long. That being said, there wasn’t much else to see here. The wind in our faces, we headed to Bona Glade for a glimpse at the federally threatened Geocarpon minimum.

Like POWs traversing a landmine field, we watched every step. We were growing more discouraged with every Geocarpon-less acre and a good hour went by before we found the treasure. We safely tip-toed around the populations of this little gem and got some decent photos. While Geocarpon was the main attraction, I was struck by the range of color and texture this extensive sandstone glade offers.

The reds and oranges of the rock mixed with the greens, grays and yellows of the mosses and lichens commingled with the deep blue of a crisp spring day.

Noticing that Lichen Glade (another sandstone glade) was nearby, we loaded up and headed out. I had wanted to visit this site for years in order to find and photo Selenia aurea. Eyes wide the second we left the parking area, we stared intently at the ground. Had we looked up, we would have seen the glade was practically carpeted with a yellow so rich it would make a number two pencil bow its lead in shame. It was a profusion of Selenia aurea.

The beauty of this yellow halo was only match by the purple haze aglow on the west facing slope of the glade.

This violet symphony beneath the bursting buds of widely spaced Post Oak trees was composed of thousands of Collinsia violacea blooms being back-lit by the setting sun.

Feeling warm from the glow of a day’s glade hopping, we drove into the night and camped at Roaring River State Park. Tip: when camping on cold spring nights, make sure you actually pack the tent and not the bag that looks like the tent but is actually a screen canopy for a picnic table.

Over morning coffee, I contemplated what was colder, last night’s windchill or the look in Brad’s eyes. I consoled myself with the belief that the vista from Chute Ridge Glade that morning bought some forgiveness.

If it didn’t, the small population of Trillium viridescens might have.

There is a section along Chute Ridge Glade dominated with an overstory of Quercus muehlenbergii and Fraxinus quadrangulata. The understory is dominated by high quality mesic woods species such as Echinacea purpurea, Elymus glaucus and Hydrastis canadensis. This Dry Mesic Limestone/Dolomite Woodland community seems to be suffering from overzealous clearing and burning. It is as though it is being interpreted as an overgrown portion of the glade rather than a community within the glade. I fear such homogenous micromanagement and a drive to achieve 100% black during prescribed fires might be doing more harm than good here. Then again, what do I know?

From here we jumped into the truck and headed for the border. Our first stop was to see the Ozark Spring Beauty well inside the Natural State that is Arkansas.

The few scattered populations of this species in the Ozarks were long thought to be disjuncts of the common eastern Carolina Spring Beauty (C. caroliniana). A recent monograph of the genus demonstrated, without doubt, that this is a distinct species. I believe it is an Ozark endemic. Subsequent searches of historic population locations in Missouri have come up empty.

Next we had a date with shale barrens in the Ouachita Mountains.

The white flowers in this photo are of Valerianella nuttallii. It is a shale obligate and a Ouachita endemic.

Here is a close-up. We witnessed many other fabulous plants in the shale barrens, but it was too windy for decent photographs. This is the very site for the newly discovered species Sabatia arkansana that was all the rage a few years ago. I would strongly recommend a visit to these treasures. They were very unique in both vegetative structure and composition.

A short hike into the forests of the Ouachita Mountains led us to the next prize; Cypripedium kentuckiense.

This plant pretty much made the trip for Brad and me. Noted Arkansas nature photographer Craig Fraiser, led us to the population that consisted of a few hundred stems. Kentucky Ladyslipper was split out of the Yellow Ladyslipper complex in the mid-1980’s and described as a new species. It differs in having a pale yellow slipper with a much larger opening. The habitat and habit are both dramatically different as well. Living plants barely resemble Yellow Ladyslippper, but pressed plants can lose the characters that differentiate the two species (especially habit and habitat). This is a great example of how field knowledge is crucial to taxonomy; a fact that is increasingly ignored as organismal biology is abandoned by universities throughout the nation.

High on great plant finds, we ventured further south. Morning found us in Texarkana, Texas. Our destination was extreme southwest Arkansas, but we were so close to Texas it would have been rude not to stop by for a few minutes. Once we were back in Arkansas, we stopped at Miller County Sandhills. The site touts 21 state listed plant species. As the name implies the area is dominated by deep sandy soils and corresponding xerophytic species. This is the first time that Brad and I really noticed a major shift in the vegetation. We could certainly taste the southern influence and we recognized very few species, which to a field botanist can be quite exhilarating but also very frustrating. Two members of the Euphorbiaceae proved to be the most interesting and strange plants at the site.

This is Cnidoscolus texanus. It took us hours to identify this thing, because its large funnelform flowers were unlike any Euphorb we had ever seen. The milky sap and a wild guess finally got us an identification.

Compared to this photo of Stillingia sylvatica in full bloom you really get a feel for the range of morphological variation in this crazy family.

On our third day we crossed into Louisiana. We had three goals for the Pelican State; 1) find Penstemon murrayanus, 2) eat a meat pie in Natchitoches and 3) get our feet wet in Cooter’s Bog.

Here is Penstemon murrayanus. It is my favorite photograph from the trip. This species is ranked S1 in Louisiana and S2 in Arkansas and Oklahoma. Evidently it is also rare in Texas. We found it growing along some weedy railroad tracks surrounded by extensive ORV trails. It seems to have an interesting autecology, but darn if I can find anything about it. Online there is an abundance of sites referring to its use as a hummingbird plant. This plus the brilliant red of the flowers has made it a favorite of the well intentioned but rather myopic “native” plant trade.

That night we feasted on meat pies in the gorgeous and historic town of Natchitoches. Don’t try to pronounce it. You have to be born there to pull it off.

The next morning, and an hour or two south of Natchitoches we found Cooter’s Bog.

Cooter’s Bog is neither Cooter’s nor a bog. This preserve, as part of the Kisatchie National Forest, belongs to the tax paying American public. It isn’t a bog if you define a bog as ombrotrophic (wet from direct precipitation and surface run-off) and a fen as minerotrophic (wet from groundwater discharge). Rainwater from the surrounding Long Leaf Pine stands percolates through deep sandy soils until it hits a clay layer. Where shallow valleys have eroded down to the clay layer, water, following the path of least resistance, emits from the ground. Even though it is acidic, it is a fen. In these nutrient deficient soils you find common carnivorous bog genera like Pinguicula (Butterworts), Drosera (Sundews), Utricularia (Bladderworts) and Sarracenia (Pitcher Plants). We saw and relished in examples of each, as well as many other fascinating taxa.

Here is a fine example of Sarracenia alata pitchers and flowers. Clumps of this amazing plant were scattered throughout Cooter’s Bog. This species rounded out a trip we took several years ago to Florida where we saw five other species. I have now seen six of the roughly 11 species in North America.

While we would have stayed for days or pushed on into Texas, the pull of real life and its burdens dragged us homeward, leaving us with only a taste of deeply southern flora. The end of a road trip always evokes a hint of melancholy in me. Like the song “The Last Fandango” or the end of “The Breakfast Club”; a satisfaction that is measured most by the degree to which you don’t want it to end. We vowed to return someday. I’ll let you know when we do.