Two days ago, the WGNSS Botany Group met in the Visitor Center parking lot on a not-as-cold and not-as-cloudy day compared to previous days with the plan to walk the Natural Wonders Trail—a relatively easy 1.3-mile loop that features mesic forest on north-facing slopes, dry forest and glades on the south-facing slopes, and a spring-fed creek that meanders through the riparian corridor below. The upland portions of the trail pass through Meramec Mosaic Natural Area, boasting an amazing diversity of natural communities and associated flora all in relatively close proximity.
We walked clockwise around the loop, which took us up and out of the riparian forest onto the north-facing slopes. Lindera benzoin (spicebush) was abundant in the understory at the lower elevations, with male and female plants both being immediately recognizable—the former sporting noticeably swollen buds that will produce the male flowers in spring, and the latter still bearing many of their now-faded berries, their earlier bright red color lost to a dull purple-black. Two members of the Betulaceae were also seen commonly in the understory—Ostrya virginiana (hop hornbeam), with its hop-like fruit clusters and almost always adorned with rich-brown marcescent leaves, and Corylus americana (hazelnut) sporting distinctive hanging male catkins.
We had scarcely reached the upper slopes when we began noticing a diversity of green foliage—not from the numerous trees and shrubs, but rather from a variety of ferns, hangers-on from earlier times that continue to find niches within the woody-dominate community that now dominate the landscape. The first example seen was a single Sceptridium dissectum (cutleaf grape-fern), its leaf now in reddish-bronze winter dress. Shortly afterwards we began to see prominent outcrops of dolomite as we neared the north-facing bluffs, their surfaces thickly covered with mosses and providing a perfect situation for Asplenium rhizophyllum (American walking fern). The long, tapering leaves of this species root at their tips and give rise to new plantlets—an asexual method of reproduction that allows a single plant to quickly colonize an entire rock surface.
The bluff faces themselves provided the greatest diversity of ferns. An unusual species observed in abundance was Cystopteris bulbifera (bulblet fern, bulblet bladderfern, or bulblet fragile fern). Unlike many ferns, the fronds of this species turn completely brown during the winter (although a few small green plantlets of what may be this species were observed growing among them). It’s most notable feature, however, is the small “bulblets” that form on the underside of its leaves, providing the plant a most unusual method of asexual reproduction.
Two Pellaea spp. (cliffbrake) we’re found as well growing from crevices on the bluff face: P. atropurpurea (purple-stem cliffbrake or purple cliffbrake) and the more uncommonly encountered P. glabella (smooth cliffbrake). In some cases the plants were growing very near each other, allowing the group an opportunity to compare and contrast. Pellaea atropurpurea is distinctive in both habit and appearance, with fertile leaflets narrowly elongate—sporangia arranged along the curled under margin and the sterile leaflets broader and “T-shaped” at the base. In addition to its dimorphic leaves, the distinctly pubescent, purplish-brown rachis separates it from P. glabella. The latter species can be found scattered throughout the Ozarks and a few northern counties and is less likely to be seen growing in soil as opposed to exposed rock.
Two more species of Asplenium were found as we continued to examine the moss-covered rock exposures, one being the commonly encountered A. platyneuron (ebony spleenwort or brownstem spleenwort)—distinctive by its purple-brown rachis and “offset” pinnae with asymmetrical basal lobes, and an as-yet-undetermined species provisionally assigned to this genus. We would see additional examples of A. platyneuron away from the rock faces growing in the soil—their fertile fronds tending to grow more erect than the sterile fronds. This same habit was seen in the eighth and final fern of the day, the very common Polystichum acrostichoides (Christmas fern) which we encountered regularly in more mesic areas of the forest floor.
Despite the botanical focus of the walk, we are all naturalists at heart and quick to notice anything that piques our natural history curiosity, regardless of what kingdom of life it pertains to, and when John called out, “Okay Ted, here’s a quiz for you,” I suspected my entomological skills would be put to the test. What he’d found were three strange-looking structures hanging from a small Ostrya sapling that would have, to anybody less-observant, been passed off as some plant fruiting structure. Of course, we knew that Ostrya fruits bore no resemblance to these structures, and when we noticed they were connected to each other and had apparently been “tied” to the twig by some sort of insect, we then guessed they may have been the fruiting structures of an as yet unidentified herbaceous plant or vine. That idea was quickly dispelled, however, when cutting into one of the structures revealed it was filled with bright yellow spheres that I can only surmise to be lepidopteran eggs, with the structures themselves and their attachments to the twig consisting of the silk that many caterpillars use to construct cocoons in which to pupate. Could these be the eggs of an usual type of bagworm moth, the females of which are typically wingless and larvicida and remain in their cocoon after emergence, where they mate, lay eggs, and die? The structures and their egg-like contents, at this point, remain a mystery, but I did collect them and am attempting to hatch the “eggs” (if that is what they are) in an effort to gain further clues about their identity.
Turning back to the east the forest changed dramatically. The tall canopy of mesic-loving hardwoods such as Quercus alba (white oak) and Acer saccharum (sugar maple) gave way to a shorter, more open canopy of trees preferring dry to xeric conditions such as Q. muhlenbergii (chinquapin oak), Rhamnus caroliniana (Carolina buckthorn), and Sideroxylon lanuginosum (wooly buckthorn or gum bumelia). Entomologist that I am, I couldn’t resist the chance to check the ground around the bases of the trunks of each of the latter, hoping to see evidence of larval activity by the spectacular and highly host-specific Plinthocoelium suaveolens (bumelia borer), but no such evidence was seen. At one point, the dry oak woodland yielded to a bona fide dolomite glade (more properly called “xeric dolomite prairie”), with evidence of mechanical removal of woody plants and prescribed burns serving as testament to dedicated management practices intended to restore and preserve the original character of the glade by park management.
The final stretch led back down into the valley, where a disturbing amount of Lonicera japonica (Japanese honeysuckle) was observed on the forest floor and growing up the smaller trees. A grove of Pinus echinata (shortleaf pine), apparently planted some time ago, looked oddly out of place given the dolomitic substrate in the area but did provide an opportunity for dramatic up views. After regrouping in the parking lot (and remarking on what a “fern-tastic” walk it had been), a number of participants caravanned to Clark Street Cade and Bakery in nearby Sullivan for a welcome resumption of the traditional post-walk lunch.
©️ Ted C. MacRae 2022