Botanizing at Elephant Rocks State Park

Granite “elephants” at Elephant Rocks State Park.

After missing the past three weeks, I was finally able to rejoin the Webster Groves Nature Study Society Botany Group for their weekly Monday outing. It was a good outing for making my return, as the group visited one of Missouri’s most famous and unusual landmarks—Elephant Rocks State Park—on what turned out to be a sunny day with unseasonably balmy conditions. Located in Acadia Valley in the heart of the St. Francois Mountains, the park is named for its main feature—one of the mid-continent’s best examples of an unusual geological feature known as a “tor.” These piles of rounded, weathered granite boulders sitting atop a bedrock mass of the same rock resemble groups of elephants lumbering across the landscape. First shaped underground in 1.5-billion-year-old granite as vertical and horizontal fractures developed in the rock and percolating water softened and degraded the rock adjacent to the cracks, the “core stones” were eventually exposed as erosion removed the overlying layers and the disintegrated rock surround the fractures, exposing the giant boulders at the surface.

Granite boulder-strewn dry-mesic upland deciduous forest.

The group explored the area along the Braille Trail, which passes through dry-mesic upland deciduous forest as it circumnavigates the tor. Oaks and hickories—primarily Quercus alba (white oak), post oak (Q. stellata), blackjack oak (Q. marilandica), Carya ovata (shagbark hickory), and C. glabra (pignut hickory)—dominate the canopy, while the understory featured Viburnum rufidulum (rusty blackhaw), Cornus florida (flowering dogwood), Prunus serotina (black cherry). Unusually abundant also was Nyssa sylvatica (black or sour gum). This small tree reaches its northern limit of distribution near St. Louis, Missouri but is more common further south. Winter bud skills are necessary to recognize the species at this time of year, which can be recognized by their alternate arrangement with three reddish-brown scales and three bundle scars. The leaves of this tree turn a brilliant red in the fall, making them desirable for landscape planting.

Nyssa sylvatica (black gum) winter buds.

Like Nyssa sylvatica, Viburnum rufidulum (rusty blackhaw) is also most common south of the Missouri River. However, in contrast to the former, the winter buds of the latter are immediately recognizable by their dark rusty-colored “velvety” buds and opposite arrangement. The tree we saw at the beginning of today’s outing was also heavily laden with fruits, a dark blue-black pruinose drupe.

Viburnum rufidulum (rusty blackhaw) winter bud.
Viburnum rufidulum (rusty blackhaw) fruits.

As we examined the blackhaw tree, we noticed a robust vine entwining its trunk and ascending high into the canopy above. Heavily laden along its length was a crop of fruits that immediately identified the vine as Celastrus scandens (American bittersweet). This native species can be distinguished from the introduced C. orbiculatus (Oriental bittersweet) at this time of year by its terminal fruits with orange instead of yellow dehiscing valves.

Celastrus scandens (American bittersweet) vine climbing Viburnum rufidulum (rusty blackhaw).
Celastrus scandens (American bittersweet) fruits.

The “fruit” theme of the day continued as we veered off the path to look at a rather magnificent specimen of Quercus marilandica (blackjack oak) and saw yet another vine bearing fruit inside its canopy. The opposite leaf remnants had us quickly thinking of some type of honeysuckle (genus Lonicera), and we arrived at Lonicera sempervirens (trumpet honeysuckle) once we noticed the fused perfoliate leaf pairs directly behind the fruits. This native honeysuckle is a desirable species and not to be confused with any of the several invasive introduced species of honeysuckle that can now be found in Missouri.

Lonicera sempervirens (trumpet honeysuckle) fruits.

Another honeysuckle relative, Symphoricarpos orbiculatus (coralberry), was heavily laden with fruit in the shrub layer. Like Lonicera sempervirens, this species is also native to Missouri and should not be confused with the invasive introduced species—especially Lonicera mackii (bush honeysuckle), which it superficially resembles but can be immediately distinguished from during this time of year by its uniquely coral-colored fruits.

Symphoricarpos orbiculatus (coralberry) fruits.

As the Braille Trail wrapped around the eastern side of its loop, we passed by a pile of granite boulders—obvious rubble fragments from the quarrying days of the area’s earlier history due to their sharp, angular shapes. Drill holes could be seen in and around the margins of some of the fragments, providing more evidence of their provenance from rock splitting operations before their eventual abandonment, perhaps not being of sufficient quality to warrant further cutting and shaping into building blocks or paving stones before shipment to St. Louis. Lichens growing sparingly on the cut faces indicated that some amount of time had passed since the stone had been cut, but it was a mere fraction of time compared to the densely colonized original exposed surfaces.

Granite rubble showing drill holes along margins.
Drill hole in granite bolder from quarrying.

Lichens were not the only forms of life taking advantage of new habitat created by past quarrying activities. Two species of ferns were found growing in protected crevices between the boulders, especially those where water was able to collect or seep from. The first was Asplenium platyneuron (ebony spleenwort), with only sterile fronds present but distinguished by the shiny dark rachis (stem) and stipe (stem base) and alternate, basally auriculate (lobed) pinnae (leaflets). The second was at first thought to be another species of Asplenium, possibly A. trichomanes (maidenhair spleenwort), but later determined to be Woodsia obtusa (common woodsia) by virtue of its all green rachis and stipe and much more highly dissected pinnae arranged very nearly opposite on the rachis. We later found the two species again growing close to each other right along the trail—completely unnoticed despite the group having passed them three times already (i.e., 25 person passes!).

Asplenium platyneuron (ebony spleenwort) sterile fronds.
Woodsia obtusa (common woodsia) sterile fronds.

A short spur took us to the Engine House ruin—originally built to repair train engines and cars; its granite skeleton still in good condition—before passing by the park’s main geological attraction: the central tor with its famous “elephants”! Standing atop the exposed granite and boulders, I try to let my mind go back half a billion years—an utterly incomprehensible span of time—when the boulders before me are still part of a giant submerged batholith underneath volcanic peaks soaring 15,000 above the Precambrian ocean lapping at their feet; life already a billion years old and dizzyingly diverse yet still confined to those salty waters.

Engine House ruin.
Exposed granite bedrock.
This formation—a stack or pile of rounded, weathered granite boulders sitting atop a bedrock mass of the same rock—is called a “tor.”
Vertical cracks in the bedrock erode into narrow gaps once exposed by erosion.

The landscape atop the tor seems sterile and barren, but like the rubble piles below it’s cracks and crevices abound with life. An especially fruticose stand of Vaccinium arboreum (farkleberry) found refuge in a protected area among some of the bigger boulders, their dark blue fruits continuing the “berry” theme of the day and providing an opportunity for the group to sample their flavor and compare to its cultivated blueberry cousins (I found their flavor to be quite pleasing, if somewhat subdued compared to what is my favorite fruit of all). Vaccinium arboreum is the largest of the three species in the genus occurring in Missouri, and the woody stems of larger plants make it quite unmistakable. Smaller plants, however, can be difficult to distinguish from the two other species, in which case the leaf venation can be used—that of V. arboreum being very open. This is another species that finds itself at the northwestern limit of its distribution in the craggy hills of the Ozark Highlands, where it shows a distinct preference for the dry acidic soils found in upland forests overlying igneous or sandstone bedrocks.

Vaccinium arboreum (farkleberry) fruits.
Vaccinium arboreum (farkleberry) leaf.

Despite this being a botany group outing, I rarely manage to go the entire time go by without finding and pointing out at least one interesting insect. Today, it was an adult Chilocorus stigma (twice-stabbed ladybird beetle) sitting on a Nyssa sylvatica trunk. This is a native ladybird, not to be confused with the introduced and now notorious Harmonia axyridis (Asian ladybird beetle), that lives primarily in forest habitats and is generally considered to be a beneficial species (although not sold for commercial use in orchards or on farms).

Chilocorus stigma (twice-stabbed ladybird beetle).

©️ Ted C. MacRae 2021

Eriopis connexa on soybean in Argentina

Eriopis connexa adult on soybean | Buenos Aires Province, Argentina

Congratulations to those of you who correctly guessed the identity of the “subject” in ID Challenge #16 as the ladybird beetle Eriopis connexa (family Coccinellidae). This is one of the most common ladybird beetles in Argentina, and during the past few weeks I have seen large numbers of these beetles in the soybean fields that I have been visiting. Coccinellids in Argentina are among the easier the groups to identify to species thanks to the excellent website Coccinellidae of Argentina. Identifying the “meal,” however, proved to be a little more difficult. Most people guessed aphids, a natural choice, but soybean aphids have not yet made it to the soybean fields of South America (thankfully!), so the victims of these predaceous beetles must be something else. There was a clue in the challenge photo that at least one person picked up on (but didn’t make the connection) in the form of small black globs stuck to the hairs of the plant on which the beetle was sitting. These are actually the fecal deposits of the bean thrips, Caliothrips phaseoli (order Thysanoptera, family Thripidae) (which I covered a year ago in A thrips is a thrips…), which for the past two seasons now has built up large populations on soybeans in Argentina. In fact, an adult bean thrips (yes, “thrips” is the correct singular form) can be seen in the above photo (which I did not notice while I was taking the photo). I’ve not yet witnessed these beetles actually feeding on a thrips, but the large numbers of thrips and beetles and near absence of any other suitable prey item makes the association almost a given.

Eriopis connexa larva on soybean | Buenos Aires Province, Argentina

Not only are the adult beetles numerous on the plants, but eggs and larvae as well. Larvae are every bit as brightly colored as the adults, with a color scheme that leaves little doubt regarding their association. In the case of this larva, I watched it roam back and forth across the soybean leaf, pausing momentarily and apparently eating something—thrips eggs I presume.

Congratulations to Mr. Phidippus and Dennis Haines, who tie for the Challenge win with 14 points each, while Gustavo and Dave tie for the final podium spot. Mr. Phidippus, however, easily takes the overall win in BitB Challenge Session #5 with a whopping total of 57 points. Mr. Phidippus—contact me for your loot! Dennis Haines and Tim Eisele take 2nd and 3rd overall honors, and full standings for BitB Challenge Session #5 are shown below.

Commentor IDC#14 SSC#10 IDC#15 Bonus SSC#11 Bonus IDC#16 Total
Mr. Phidippus 11 11 9   12   14 57
Dennis Haines 9 4 2   10 1 14 40
Tim Eisele 8 6 2   13   6 35
Roy 5 6 7   10     28
Mike Baker 7   9       10 26
Dorian Patkus     9   11 4   24
David Winter 3   9       10 22
Gustavo             12 12
HBG Dave             12 12
Marlin 12             12
FlaPack 10             10
Laurie Knight 2       8     10
Doug Yanega         9     9
Brady Richards       4   3   7
John Oliver   6           6
George Sims 2 2 2         6
Richard Waldrep   6         6
Arpad Hervanek 4             4
Roxane Magnus 4             4
dragonflywoman       4     4
Wayne K         4     4
itsybitsybeetle         4     4
fatcatfromvox 2             2
Emily Gooch 1             1
Sean Whipple     1         1
Jon Q             1 1

 

Copyright © Ted C. MacRae 2012

Bichos Argentinos #11 – Takes Two to Tango

Epilachna vigintioctopunctata (vaquita de las solanáceas) | Buenos Aires, Argentina

Another of the insects that I photographed at La Reserva Ecológica Costanera Sur, Buenos Aires, Argentina during my early March visit.  I found quite a few of these beetles feeding on the newly sprouting growth from cut stumps of a small, multi-stemmed tree.  At first I thought they were leaf beetles of the family Chrysomelidae because of the way they were actively feeding on the fresh, succulent growth; however, a closer look quickly revealed them to be members of the family Coccinellidae (ladybird beetles).  Their phytophagous, gregarious behavior immediately identified them as members of the subfamily Epilachninae, and in fact they bear a remarkable resemblance to Epilachna varivestis (Mexican bean beetle) and E. borealis (squash lady beetle) – the best known examples of this subfamily in North America.

Armed with confidence in at least a subfamilial placement, I looked for references on the group and quickly found a reasonably recent revision of the subfamily for the entire Western Hemisphere (Gordon 1975) – jackpot!  I reasoned an abundant species seen in the heart of the 3rd largest city in South America would likely show up on page one, but after several increasingly careful passes through the entire revision, it became clear that whatever species this was, it was not among the nearly 300 species (2/3 of them in the genus Epilachna) treated in that work. 

Now, the exuberant, young, not-very-sage entomologist that I was 30 years ago would have immediately gotten all excited that I had found a new species, but the older, battle-tested, more cautious entomologist that I am now instead started suspecting I was dealing with an introduced species.  After all, some of the insects and plants I’ve already featured from this man-made nature reserve are introduced.  I figured as abundant as the beetles were, the species had to be featured on some website, so I started with the obvious and Googled “Coccinellidae Argentina,” clicked on the very first result (appropriately titled Coccinellidae of Argentina), and found a seemingly authoritative site with links to the different subfamilies.  Clicking on Epilachninae and scanning the photos, there it was – Epilachna vigintioctopunctata (28-spotted ladybird beetle).  Native to India and southeastern Asia, this species is well known for its attacks on numerous solanaeous and cucurbitaceous crops (Richards 1983).  It made its first appearance in the Western Hemisphere in southern Brazil (Schroder et al. 1993) and in 1994 was observed on experimental eggplant plots at the School of Agronomy, University of Buenos Aires (Folcia et al. 1996).  Poetically, those initial specimens were sent to Robert Gordon at the U.S. National Museum (and author of the Western Hemisphere revision), who confirmed their identity.  It seems that Argentinians are not the only ones that like to tango!

REFERENCES:

Folcia A. M., S. M. Rodriguéz and S. Russo. 1996. Aspectos morfológicos, biológicos y de preferencia de Epilachna vigintioctopunctata Fabr. (Coleoptera Coccinellidae). Boletin de Sanidad Vegetal Plagas 22:773–780.

Gordon, R. D. 1975. A revision of the Epilachninae of the Western Hemisphere (Coleoptera: Coccinellidae). U. S. Department of Agriculture, Technical Bulletin No. 1493, ii+409 pp.

Richards, A. M.  1983.  The Epilachna vigintioctopunctata complex (Coleoptera: Coccinellidae).  International Journal of Entomology 25(1):11–41.

Schroder, R. F. W., M. M. Athanas and C. Pavan. 1993. Henosepilachna vigintioctopuctata (Coleoptera-Coccinelidae), new record for Western Hemisphere, with a review of host plants. Entomological News 104(2):111–112.

Copyright © Ted C. MacRae 2011

Brazil Bugs #2

A few more photographs from this past week in Campinas, Brazil.  It rained during the afternoon but stopped by the time I arrived back at the hotel, allowing me to stroll the lavishly landscaped grounds during the mild evening hours.  There is a pink-flowered shrub forming a hedge row in back of the hotel that is highly attractive to many types of insects.  The identity of the shrub remains a mystery to me, and most of the insects I’m finding on it I can recognize only to family – I’m hoping the hotel staff will be able to name the former and that the readers of this blog might be able to provide IDs for the latter.

Calycopis sp. poss. origo (Lepidoptera: Lycaenidae). ID by Dave Hubble and Chris Grinter.

It took a bit of effort to find an unobstructed view of this hairstreak butterfly (family Lycaenidae) as it visited the flowers within the shrub.  Every time I tried to move foliage out of the way to get a good view, the butterfly became alarmed and flew to another part of the hedge row.  My antics drew the attention of a hotel worker, who was apparently interested enough in what I was doing to act as a spotter whenever the butterfly flew to help me relocate it.  Eventually I got a few shots that I was happy with, including the above.

A flesh fly (Diptera: Sarcophagidae).

I presume this to be a type of flesh fly (family Sarcophagidae) based on the stout bristles and color pattern that seems typical for the family.  I like the striking contrast in coloration between the fly and the flower.  There are a few fly bloggers who I’m hoping might be able to give a better identification.

A potter/mason wasp? (Hymenoptera: Vespidae).

This appears to me to be some kind of potter or mason wasp (family Vespidae, subfamily Eumeninae) – it was a bit smallish at only about 12mm in length.  I hope one of the knowledgeable wasp bloggers out there (ahem… Eric?) can at least confirm this level of identification and perhaps the tribe or genus as well. 

Azya orbigera (Coleoptera: Coccinellidae). ID by Tucker Lancaster.

Every ladybird beetle (family Coccinellidae) I’ve ever seen is some variation of black and red/orange/yellow and has a smooth, glabrous appearance.  This beetle is cobalt blue with a dense pubescence over the dorsal surface, but it still seems to me to be some type of ladybird beetle.  It was a tiny little thing, so I suppose it could be one of the multitude of small beetle families with which I am unfamiliar.

Quedas sp.? (Hemiptera: Cicadidae).

This cast cicada exuvium was not on the shrub, but on a nearby tree at about eye level.  I really wish I could have seen the cicada that emerged from it, because this is certainly the biggest cicada exuvium I have ever seen.  I was about to simply label it “family Cicadidae” but seem to recall that cicada higher classification is in a bit of flux these days.  At any rate, given its great size I wonder if it might represent one of the giant cicadas in the genus Quesada.

I still have many more insect photographs from the past week and will certainly increase that number over the next week as well.  Stay tuned!

Copyright © Ted C. MacRae 2011