After lacking the previous three weeks, I used to be lastly in a position to rejoin the Webster Groves Nature Examine Society Botany Group for his or her weekly Monday outing. It was a great outing for making my return, because the group visited one in all Missouri’s most well-known and weird landmarks—Elephant Rocks State Park—on what turned out to be a sunny day with unseasonably balmy situations. Situated in Acadia Valley within the coronary heart of the St. Francois Mountains, the park is called for its important characteristic—one of many mid-continent’s finest examples of an uncommon geological characteristic often known as a “tor.” These piles of rounded, weathered granite boulders sitting atop a bedrock mass of the identical rock resemble teams of elephants lumbering throughout the panorama. First formed underground in 1.5-billion-year-old granite as vertical and horizontal fractures developed within the rock and percolating water softened and degraded the rock adjoining to the cracks, the “core stones” had been ultimately uncovered as erosion eliminated the overlying layers and the disintegrated rock encompass the fractures, exposing the large boulders on the floor.
The group explored the realm alongside the Braille Path, which passes by means of dry-mesic upland deciduous forest because it circumnavigates the tor. Oaks and hickories—primarily Quercus alba (white oak), publish oak (Q. stellata), blackjack oak (Q. marilandica), Carya ovata (shagbark hickory), and C. glabra (pignut hickory)—dominate the cover, whereas the understory featured Viburnum rufidulum (rusty blackhaw), Cornus florida (flowering dogwood), Prunus serotina (black cherry). Unusually plentiful additionally was Nyssa sylvatica (black or bitter gum). This small tree reaches its northern restrict of distribution close to St. Louis, Missouri however is extra widespread additional south. Winter bud abilities are vital to acknowledge the species presently of yr, which will be acknowledged by their alternate association with three reddish-brown scales and three bundle scars. The leaves of this tree flip a superb purple within the fall, making them fascinating for panorama planting.
Like Nyssa sylvatica, Viburnum rufidulum (rusty blackhaw) can also be commonest south of the Missouri River. Nonetheless, in distinction to the previous, the winter buds of the latter are instantly recognizable by their darkish rusty-colored “velvety” buds and reverse association. The tree we noticed in the beginning of at present’s outing was additionally closely laden with fruits, a darkish blue-black pruinose drupe.
As we examined the blackhaw tree, we seen a sturdy vine entwining its trunk and ascending excessive into the cover above. Closely laden alongside its size was a crop of fruits that instantly recognized the vine as Celastrus scandens (American bittersweet). This native species will be distinguished from the launched C. orbiculatus (Oriental bittersweet) presently of yr by its terminal fruits with orange as a substitute of yellow dehiscing valves.
The “fruit” theme of the day continued as we veered off the trail to have a look at a fairly magnificent specimen of Quercus marilandica (blackjack oak) and noticed one more vine bearing fruit inside its cover. The alternative leaf remnants had us rapidly pondering of some kind of honeysuckle (genus Lonicera), and we arrived at Lonicera sempervirens (trumpet honeysuckle) as soon as we seen the fused perfoliate leaf pairs instantly behind the fruits. This native honeysuckle is a fascinating species and to not be confused with any of the a number of invasive launched species of honeysuckle that may now be present in Missouri.
One other honeysuckle relative, Symphoricarpos orbiculatus (coralberry), was closely laden with fruit within the shrub layer. Like Lonicera sempervirens, this species can also be native to Missouri and shouldn’t be confused with the invasive launched species—particularly Lonicera mackii (bush honeysuckle), which it superficially resembles however will be instantly distinguished from throughout this time of yr by its uniquely coral-colored fruits.
Because the Braille Path wrapped across the jap aspect of its loop, we handed by a pile of granite boulders—apparent rubble fragments from the quarrying days of the realm’s earlier historical past because of their sharp, angular shapes. Drill holes could possibly be seen in and across the margins of a few of the fragments, offering extra proof of their provenance from rock splitting operations earlier than their eventual abandonment, maybe not being of ample high quality to warrant additional chopping and shaping into constructing blocks or paving stones earlier than cargo to St. Louis. Lichens rising sparingly on the minimize faces indicated that some period of time had handed because the stone had been minimize, but it surely was a mere fraction of time in comparison with the densely colonized unique uncovered surfaces.
Lichens weren’t the one types of life benefiting from new habitat created by previous quarrying actions. Two species of ferns had been discovered rising in protected crevices between the boulders, particularly these the place water was in a position to acquire or seep from. The primary was Asplenium platyneuron (ebony spleenwort), with solely sterile fronds current however distinguished by the shiny darkish rachis (stem) and stipe (stem base) and alternate, basally auriculate (lobed) pinnae (leaflets). The second was at first regarded as one other species of Asplenium, presumably A. trichomanes (maidenhair spleenwort), however later decided to be Woodsia obtusa (widespread woodsia) by advantage of its all inexperienced rachis and stipe and far more extremely dissected pinnae organized very almost reverse on the rachis. We later discovered the 2 species once more rising shut to one another proper alongside the path—fully unnoticed regardless of the group having handed them 3 times already (i.e., 25 individual passes!).
A brief spur took us to the Engine Home wreck—initially constructed to restore prepare engines and vehicles; its granite skeleton nonetheless in good situation—earlier than passing by the park’s important geological attraction: the central tor with its well-known “elephants”! Standing atop the uncovered granite and boulders, I attempt to let my thoughts return half a billion years—an totally incomprehensible span of time—when the boulders earlier than me are nonetheless a part of a large submerged batholith beneath volcanic peaks hovering 15,000 above the Precambrian ocean lapping at their ft; life already a billion years previous and dizzyingly numerous but nonetheless confined to these salty waters.
The panorama atop the tor appears sterile and barren, however just like the rubble piles under it’s cracks and crevices abound with life. An particularly fruticose stand of Vaccinium arboreum (farkleberry) discovered refuge in a protected space amongst a few of the greater boulders, their darkish blue fruits persevering with the “berry” theme of the day and offering a possibility for the group to pattern their taste and examine to its cultivated blueberry cousins (I discovered their taste to be fairly pleasing, if considerably subdued in contrast to what’s my favourite fruit of all). Vaccinium arboreum is the most important of the three species within the genus occurring in Missouri, and the woody stems of bigger vegetation make it fairly unmistakable. Smaller vegetation, nonetheless, will be tough to tell apart from the 2 different species, wherein case the leaf venation can be utilized—that of V. arboreum being very open. That is one other species that finds itself on the northwestern restrict of its distribution within the craggy hills of the Ozark Highlands, the place it exhibits a definite choice for the dry acidic soils present in upland forests overlying igneous or sandstone bedrocks.
Regardless of this being a botany group outing, I not often handle to go the complete time go by with out discovering and mentioning no less than one attention-grabbing insect. Immediately, it was an grownup Chilocorus stigma (twice-stabbed ladybird beetle) sitting on a Nyssa sylvatica trunk. This can be a native ladybird, to not be confused with the launched and now infamous Harmonia axyridis (Asian ladybird beetle), that lives primarily in forest habitats and is mostly thought of to be a useful species (though not offered for industrial use in orchards or on farms).
©️ Ted C. MacRae 2021