Despite the relatively long drive from St. Louis, a healthy group of 15 showed up for this past Monday’s WGNSS Botany Group outing at Hughes Mountain Natural Area; participation no doubt helped out by a spectacular forecast (sunny with highs in the 70s) and near-peak fall colors. Hughes Mountain is situated in the northern portion of the St. Francois Mountains. At its summit is Devil’s Honeycomb—a barren expanse of uniquely fractured Precambrian rhyolite formed by the gradual cooling of magma inside a volcano that was then exposed over 1.5 billion years of erosion. Devil’s Honeycomb is one of Missouri’s geologic wonders, and it’s rocks are among the oldest exposed rocks in all of North America.
Rocks are not the only items of interest here; the igneous substrate results in acidic conditions that affect the flora in equally interesting ways. This is most pronounced in the igneous “glades” (more properly called xeric igneous prairies) where the soils are too thin and conditions too dry to support the growth of trees, offering refugia for grasses and other herbaceous plants more typical of the western grasslands to persist. Surrounding the glades are dry and dry-mesic upland deciduous forests of oak and hickory featuring a rich shrub layer and open woodland-adapted herbaceous plants.
Beginning on the trail from the parking lot, John Oliver pointed out a stand of tall, now leafless sumacs which nearly everybody (including this author) assumed to be Rhus glabra (smooth sumac) due to their size. In fact, despite their size, they proved to be R. copallinum (winged sumac), with the ID confirmed by a few persisting leaves and their distinctive axial “wings.” John pointed out that an easy winter ID tip for this species is the fruiting structures, which nod distinctively after first frost (those of R. glabra do not).
Ascending the trail through the dry-mesic forest towards the first set of glades, we noted the brilliant colors of small Acer rubrum (red maple) saplings in the understory. When their leaves finally drop, they will be more difficult to distinguish from A. saccharum; however, their rounded rather than elongated buds will still allow differentiation.
Several of the oaks were examined, with most thinking they were largely Quercus shumardii (Shumard’s oak) and Q. velutina (black oak)—both similar to each other but the latter bearing larger, grayer, pubescent, quadrangular terminal buds. Approaching the glades, Q. marilandica (blackjack oak), Carya texana (black hickory), and Ulmus alata (winged elm) became more abundant, all three much preferring the drier conditions found around the glade margins. An interesting feature of the latter (in addition to the distinctive, corky ridges on the twigs), is the leaves, which are smaller than those of most other elms but tend to grow larger towards the terminus of the twig. They also tend to be much less asymmetrical at their base than other elms.
Very little was left in bloom, but the remnants of recent bloomers were still evident. Solidago petiolaris (downy goldenrod) and Symphyotrichum anomalum (many-rayed aster) were common along the trail and still recognizable, their showy flowers gone and replaced by developing seeds. Hieracium sp. prob. gronovii (beaked hawkweed) was found nestled among mosses perched on a rhyolite shelf, the flowers gone but the leaves still green and distinctively hairy. Hypericum gentianoides (pineweed) was found on the glades proper, most with their stems and leaves turning red but the occasional plant still green enough to allow crushing its stems and enjoying its orange-like fragrance. Bucking the trend, however, was a small patch of Solidago nemoralis (old-field goldenrod), it’s yellow flowers fresh and bright in defiance of the calendar’s call to senescence. A small jumping spider in the genus Phidippus took advantage of the lingering greenery, hiding among the leaves in hopes of finding equally persistent prey.
The benefits of management efforts by the Missouri Department of Conservation in the area’s forests were more evident than ever. Between the first set of glades and the main glades surrounding the summit, a rich shrub layer dominated by Rhus aromatica (fragrant sumac) stretched endlessly under an open woodland of oak and hickory, the latter turning the canopy bright yellow in vivid contrast to the orange and red shrub layer beneath. Such open woodlands were once common in pre-settlement Missouri but are now rare due to the elimination of fire in the landscape and its mediating impacts.
Entering the main glades, the group made their way up towards the summit and Devil’s Honeycomb, while Ted and Sharon stayed back to take a closer look at and photograph a robust colony of Cladonia cristellata (British soldiers) growing under Juniperus virginiana (eastern red-cedar). Lichens, of course, are unique in the world of vegetation in that they are a composite organism—a fusion between a fungus and another organism (usually a green alga or cyanobacterium) capable of producing food via photosynthesis. None of these groups of organisms are considered plants in the modern sense, and, in fact, fungi are more closely related to animals than they are to plants. Nevertheless, the convergence in appearance, habitat, and ecology of lichens with plants puts their study much more in the realm of botany than zoology.
The group arrived at the summit just in time to enjoy spectacular vistas under crystal blue skies with wisps of clouds and the balmiest temperatures one could possibly hope for in early November.
©️ Ted C. MacRae 2021