Barred Owl (Strix varia)

Let's take a moment to celebrate the continued success of the Arboretum as a functional local ecology; we've got another photo of a barred owl (Strix varia)! Is it the same owl that was recently photographed by Professor Amy Hammond? If it's not, we've got at least two resident strigids. If it is, we've got one that is rather comfortable with us. We're winning either way.

The photos below were submitted by Centenary student Hilary Pillaro. 

The owl is pictured in the center of the frame, fairly close to the ground. It is perched above a sprinkler that was operating the previous night. The arboretum's inhabitants (robins, rodents, bugs, squirrels, toads, etc...) have begun congregating around the sprinklers due to a month of hot & dry weather.

Barred Owl (Strix varia) photographed by Hilary Pillaro

August 24, 2026

Keeping looking up! 

Feral Honey Bees (Apis mellifera)

The Eurasian Honey Bee (Apis mellifera) has been present in North America for around four centuries. This interesting bug has been living alongside human settlements for thousands of years, semi-domesticated and feral. Our blog post concerns the latter variety, although where they came from and exactly what they are will remain a mystery. Apis mellifera has between two to three dozen subspecies, some of which have been repeatedly introduced to our area. Once they've gone feral and potentially hybridized with other honey bees, only a genetic test would be able to settle exactly what they are.

 

They've made their home in the middle of the arboretum, in a damaged trunk of a loblolly pine (Pinus taeda). If anyone happens to be looking up, they will only notice a dark spot along the trunk. This honey bee home is nondescript, totally flying under the radar.

A closer inspection, with good lighting, will reveal the frenzy of eusocial activity.

These bees aren't bothering anyone, and their hive is protected by being fifteen or twenty feet above ground. It's unlikely that they'll cause a problem and they will definitely be aiding local pollination. 

Look Up!

How many folks walk around with an upward gaze? Straight ahead with a slight downward tilt seems like the best way to avoid tripping and stay safe. Walking paths are expected to be free of twigs and branches, so much of the time we can get away with looking downward (at our phones) while walking. But this week in the arboretum, we received a nice reminder to look up. 

This barred owl (Strix varia) was spotted in the middle of the arboretum. First seen perched on the railing of the long white wooden bridge that runs between the Student Union Building and Mickle Hall. Presumably it was hunting a critter scurrying around in the drainage channel. Upon being approached, the barred owl flew upward into this nearby pecan tree. Professor Amy Hammond snapped this photo.

 

Keeping our eyes to the ground (or to the phone) results in us failing to appreciate the intrigues occuring directly above us. How many birds of prey did you pass under today? Barred owls aren't seen every day in the arboretum, but neither are they uncommon. Who-who knows how common they are? Let's look up more often and try to get another owl photo.

French Mulberry (Callicarpa americana)

 

Toward the end of spring, we noted that the French mulberry flowers are without pizzazz (read here). The flowers are small and hidden and they simply do not dazzle.

The fruits, however, are wonderfully bright. Their sharp coloration is much appreciated in the August landscape. Some fruits are ripening now, while other shrubs are on a different timer, ripening through the month of August and into September. 

 

This shrub near the southwest corner of Mickle is covered in ripe fruits, but other shrubs in the arboretum have yet to begin the process.

Fruits are edible straight from the shrub, but they do taste better when used to make jelly. Yum!

Cypress Rust or Cypress Galls?

As students are currently flooding back onto campus and things are once again shifting into active term, your arboretum curator has taken the opportunity to remove branches and limbs from walking spaces. Living limbs, dead ones, branches covered in leaves, bare ones, and even the soft needles of cypress trees are being pruned away from the "head spaces" across the arboretum. While performing this seasonal maintenance near the Student Union Building, we noticed some rust-like growths in the pruned branches. Having struggled against cedar-apple rust (Gymnosporangium juniperii) for more than a decade, we are well-accustomed to unsightly rusts. But the simultaneous presence of white and purple growths on nearby branchlets made us do a double-take. 

 

What is going on with these cypress leaves? The unexpected amount of color variation gave us pause and attracted our attention.

 

These aren't rust at all! They're galls! Galls are growths created by tiny flies called cypress gall midges (Taxodiomyia sp.). These little critters are obligate parasites of the cypress, and the adult flies are terribly small. If you carefully dissected the large green-yellow gall on the right of the above photo, you could find tiny larvae crawling around in there, exerting chemical/enzymatic control over the tree. How odd!

Here we can see the life-cycle progress of gall-formation. They begin as white, budding, geometric-like structures seen on the left, which ripen into a frosty purple, pictured center. The galls then continue to mutate into more bulbous rusty lumps, like the one pictured on the right. These eventually fall from the tree and overwinter on the ground, finally releasing new midges during the following summer.

Beginning stage of gall development

Further development

Toward the end of gall development

 

See our previous post on this baldcypress from September 2019, which ends with a mention of this issue! Much water has passed under the bridge of life since then, but some things, including the Cecidomyiidae family of gall midges, never change.

 

 

External Link

NC State Extension Fact Sheet on Cypress Gall Midge 

Montezuma Bald Cypress (Taxodium mucronatum)

The genus Taxodium has three living members. First and greatest is T. distichum, our famous bald cypress, which is found up and down the Mississippi embayment, the Gulf Coast, and the Atlantic seaboard from Delaware to Miami. Less well-known is T. ascendens, the pond cypress, which has a similar but much reduced range. Finally there is T. mucronatum, the Montezuma bald cypress, whose native range is mostly within Mexico and Central America, although a few of the Texas counties on the Rio Grande are counted as well.

Consequently, the Montezuma bald cypress isn't native to Louisiana or the southeastern United States. But having all three Taxodium species in the arboretum allows any visitor to see for themselves the dissimilarities that exist within this one genus.

There are two Montezuma bald cypresses in the arboretum collection. Way back in the '80s, Professor Leuck purchased their predecessors from Woodlanders Nursery (Aiken, SC), and he planted them in his yard on Albany Avenue in Shreveport. In 1994, Professor Leuck collected and rooted two cuttings from the Albany Avenue property, and in the fall of 1995, he planted the new trees on the periphery of the arboretum, near the lower level entrance to the Student Union Building.

The Montezuma bald cypresses are tucked in between the two staircases, flanking the doorway. Today, this is the entrance to the Post Office. Thirty years ago in 1995, it was the entrance to the campus bookstore. These trees have witnessed a great deal of change.

 

On the left side of the doorway, we see the southern-most tree. Its trunk is noticeably thicker.

 

On the right side of the doorway, we see the northern-most tree. Its trunk has a smaller diameter. Given that these trees are growing far north of their native zone, maybe its microclimate exposure to colder weather makes this the slower-growing specimen.

The staircase provides a neat vantage point, and it also allows us to see the leaves up close. Over the years, the lower limbs of the cypresses were removed so that pedestrians could easily move about without ducking all of those branches.

The soft, feather-like needles are arranged either in an alternate or spiralling pattern. The needles are mostly evergreen under good conditions, lasting until spring when they drop to make way for new growth.

Here we see approximately 40 pairs of needles on one branchlet. Unfortunately the number of needles varies quite a bit and isn't particularly diagnostic between species. The small blunted tips of each needle gave rise to the binomial species name; mucronatum refers to an abruptly angled point.

The southernmost tree has the thicker trunk, potentially because it has access to more sunlight. Its trunk has fewer lower limbs.

The trunk with the smaller diameter has more lower limbs. 

An additional photo, showing the relative heights of the two trees, would be useful here. Perhaps the thinner-trunked tree is taller. And we forgot something else! In the future we need to add photos of these trees' cypress knees... just kidding! They don't have any. This is typical of Taxodium mucronatum, and the absence of knees on a cypress should set off alarm bells that one isn't dealing with the typical bald cypress.

 

 Useful external links

US Forest Service page on T. mucronatum 

USDA Plant Database profile on T. mucronatum 

Post Oak (Quercus stellata)

 

Storm winds shook the trees of the arboretum last week, rustling branches and scattering loose twigs onto the ground. Although messy, this provides us with ample opportunity to study and compare a broad sample of leaves. Our big old mature trees tend to drop only their lower branches, leaving their fresh summer-time foliage out of reach. One such specimen is the aged post oak (Quercus stellata) standing near the Student Union Building. Its gnarly branches are way up high, but this week some of those upper story leaves were knocked out of the canopy.

From the ground, there were a lot of nice leaves to sort through. We see variations in size and shape, but the general shape description runs the same: roughly cross-shaped with five lobes. Although, does anyone else get the feeling that these leaves are reaching out for hugs?

This photo aptly captures one prominent quality of the leaf surface: shininess! With the leaves laying flat on the pavement, sunlight bounces off the leaf surface.

Standing the leaf up against the wet bricks takes away some of the shine.

Irregular leaves make tree identification difficult. But, if you already know that it's a post oak, you can appreciate the irregularity, and say, "Hey, that's an interesting shape! Cool."

An irregular, but still more-or-less recognizable, post oak leaf

Laurel Cherry (Prunus caroliniana)

 

Prunus is a famous, useful, and diverse genus. When you're "kind of a big deal," you typically have more problems come your way.

Here we see sap leaking from regularly-spaced wounds on the trunk of this laurel cherry (Prunus caroliniana).

This is likely the early stages of a condition arborists call "gummosis." The French botanist Auguste Trécul (1818-1896) was first to note, circa 1860, that a condition resulting in a superabundance of sap around a pathological zone could result from a variety of maladies. That name refers to the liquefaction of a tree's inner wood material and its leaking from wounds in the tree. This gummosis, or Gummibildung and even Gummifluss, as the Germans call it, can help protect a tree by isolating infected wood between hardened, protective plates. As it is really more of a physiological response than a disease itself, there is no singular cause of gummosis; it can result from insect damage, climatological stress, or infection by bacteria and fungi. 

Here we can see an old wound and the gummosis above it.

Back in June, this tree was placed on the docket for removal, primarily because of its significant lean. You can read that post here. The gummosis is not the reason for removal, but it did speed up the process. Enquiring minds want to know―what does the inner bark look like given the external gumminess? Is there a bug infestation or is it rotting? So the Faustian spirit urges, "Cut it down! Let's find out!"

 We are fortunate to have a volunteer ready to take its place. We'll stake that one and try to avoid the leaning tower of laurel.

In order to avoid destroying the smaller laurel cherry at the base, we first took out all the branches. Cutting most of the way through allowed us to extract the plant material slowly.

Here the tree has been separated into trunk and branches for easier disposal.

Here we can see the damage at the base of the trunk, which probably gave rise to the gummosis. Our working theory is that this damage was isolated and more-or-less healed by the tree. Later attacks by bugs or sapsuckers, in a vertical line from this damage, resulted in the tree leaking sap due to its proximity to the old wound.

The trunk ought to be round—and a crescent-shaped portion is clearly missing. What we don't see here is a lot of rotten material, a bug infestation, fungal infection, or other bad signs. The tree was, at least right now, apparently healthy despite the manifestation of gummosis. Nevertheless, we stand by the decision we made to cut it down, in large part due to the uncorrectable lean. In an unexpected turn, this newly cut lumber produced an aroma which corresponded precisely to a cherry soda.

All cleaned up and immediately replaced by the volunteer, who will reap great rewards in sunlight, nutrients, and water.

A Bacterial Gummosis of Cherries (1911) by F. L. Griffin

Gummosis of Prunus & Citrus (1911) by Ormond Butler

Solomon's Seal (Polygonatum biflorum)

The arrestingly-named Solomon's seal (Polygonatum biflorum) is a handsome herbaceous plant. Its obscure common name is well-paired with its genus name, Polygonatum (which comes from the Greek gonatos)  and means "many-kneed." Do plants have knees? What does all this mean? We won't dwell on the unanswerable. There are a few dozen species in the genus, but most find their home in East Asia, far from Caddo Parish, Louisiana. 

As far as names go, we have a problem; our current signage turns out to be inaccurate. The arboretum catalogue shows two collection dates for hairy Solomon's seal (Polygonatum pubescens), both dating from the '90s. In 1991, Professor Ed Leuck collected a few plants from within Shreveport's city limits, on Line Avenue. A healthy patch still grows under the origianl red buckeye plants. In 1996 Jack Price of Blanchard donated six pots. Those plants have thrived on the southwest side of the long wooden bridge that runs from the Student Union Building to Mickle Hall. This patch continues to grow out into the lawn. Plants were collected from the grassy area and then transplanted to other areas of the arboretum, resulting in two additional patches of Solomon's seal. So, there are four total patches of Solomon's seal, and the original two patches are marked with green signs that read 'Solomon seal (Polygonatum pubescens)'. 

This is a relatively new patch of Solomon's seal. In 2023, we relocated a couple of plants to this spot, alongside a young black cherry (Prunus serotina). The black cherry has since grown tall, shading the Solomon seal.

The fruits were noticed several weeks ago. 

Leaves alternate and have noticeable ridges or veins.

As the bell-like flowers of Solomon's seal descended daintily and prettily from the stalks, so now do the berries.

These fruits greatly resemble blueberries, although they are much more firm. Be careful! NC State Extension claims, "The berries, if eaten, are poisonous."

Dark blue round fruits measure less than ½ inch across.

 

Squeezing the large fruit opens the bright green interior, revealing numerous seeds. Seven seeds came from one fruit. Another yielded four seeds.

 

Looking at the current classification information for Polygonatum in the United States shows P. pubescens and P. biflorum are the two major species east of the Mississippi. However, a distribution map clearly shows that P. pubescens is not found in the Deep South; its homelands begin in the mountainous, cooler climates of Kentucky and Tennessee. Since the distribution map for P. biflorum makes much more sense in covering the entire eastern half of the USA, we needed to take a closer look at the plants currently growing in the arboretum.  

Descriptions for both species state the fruits are similar. Descriptions differ for flowers, leaf size and shape, and the presence of hairs. Since flowers aren't available in late summer, all four patches of Solomon's seal were studied for leaf size and shape and the presence of hairs. 

This egg-shaped leaf suggests P. biflorum.

These narrower, lanceolate-shaped leaves suggest P. pubescens. 

These leaves are from two different patches. Do we have two different species or different light-conditions? The top leaf was found in full-shade. The bottom leaf was found in partial shade.

 

 

Within the arboretum's collection, leaf size and shape suggest that we have two different species of Solomon's seal. However, the common names dwell on the presence of leaf hairs, and although the leaves varied in size and shape, no hairs were seen on any stems or leaves. All surfaces felt and looked smooth. 

This is the underside of the leaf. We see spots, but nothing fuzzy. 

The underside is smooth. Leaves and stems from all four patches were examined, and nothing resembling hairs was detected. 

Based on species distribution and the total absence of hairs, we shall change the arboretum catalogue to note that we have Polygonatum biflorum, rather than Polygonatum pubescens. And, in the spring, we must study the flowers to see if they can give us any other clue as to the correct species label.

 

 

For more information about this species, please consult the following online sources:

USDA Plant Database Info for Smooth Solomon's Seal

USDA Plant Database Info for Hairy Solomon's Seal

Flora of North America Species comparison for these two plants 

Plants of Louisiana

NC State Extension