Crosby Arboretum
Louisiana Master Naturalist's Field Trip
Yesterday, Julie and I joined some other members of the Louisiana Master Naturalists of Greater New Orleans on a field trip to Crosby Arboretum. It was just a casual trip, the kind of walk where if you go 10 feet in half an hour, you’re just fine with that.
We stopped to identify1, research, discuss and document dozens and dozens of organisms, way too many for a blog post, so I’m just going to include some of the more interesting ones and some of the things I wanted to research after the trip.
The Crosby Arboretum is located at the site of an old strawberry farm in Picayune, Mississippi. After L.O. Crosby died in 1978, his family decided to develop the land that he loved into an interpretive center for native plants. With the help and collaboration of Louisiana State University and Mississippi State University, they ultimately dedicated sixty-four acres of exhibits educating on indigenous plant communities—a revolutionary approach to arboretum planning that balanced natural habitat and planned design to celebrate local native flora by preserving, enhancing, and even re-creating regional ecosystems.
Immediately after we started our walk, we stopped for our first plant: the golden club.
Julie’s standard questions during nature observations are a little different than mine. I use “I notice, I wonder, it reminds me of…”. Her questions are usually “What is it” and “Can I eat it?”
As with many plants foraged in nature, the answer is not a simple yes or no. The entirety of the golden club is poisonous, but with judicious harvesting, cleaning and cooking, it can be safely eaten2.
Speaking of eating, the blueberry flowers are in bloom, and we grow them at home for our own use—at least the ones we can harvest before the racoons can.
The yaupon holly berries are ripe and are an excellent food for many birds. Julie likes this plant3 not because of the berries (which are toxic to humans) but because of the leaves and stems, which contain caffeine. If society ever collapses and coffee is not available, these will be worth their weight in gold.
The scientific name for yaupon holly is Ilex vomitoria. I tend to remember that because of the berries, but the name actually comes from the plant’s use by Native Americans in ceremonial practices. The plant was traditionally used to make an infusion containing caffeine, which when consumed in large quantities, caused a cleansing effect, often leading to vomiting. Despite its scientific name, when brewed properly and consumed in moderation, the tea is perfectly safe.
The only other plant endemic to North American that contains caffeine is Ilex cassine, commonly known as dahoon holly or cassena.
Fire and Native Habitat
A Short Rant about Conservation
The arboretum uses prescribed burns to maintain native habitat. Many plants evolved to thrive in frequent, low-level fires long before humans arrived. If you don’t deliberately create controlled fires periodically, the result could be a harmful wildfire that harms the habitat rather than rejuvenating it.
As we built cities closer and closer to natural areas, fire suppression became the norm. Understory started growing taller and thicker, woody plants began encroaching into bogs, and the plants that depend on fire to germinate or compete began to decline. The lack of regular fires, along with the draining or filling of sensitive wetlands, has resulted in a 97.5% loss of pitcher plant habitat on the Gulf Coast. Crosby Arboretum is one of the few remaining places to see this threatened plant.
Longleaf pines, which once covered an estimated 90 million acres, now cover less than 3 percent of their original range, and are a preferred habitat to the endangered red-cockaded woodpecker. Without fire, loblolly4 pine, since it produces many fast growing seedlings, can quickly crowd out the slower growing longleaf. These two trees support different types of habitat density (the amount of understory) as well as wildlife and plant communities. The loss of longleaf pines would result in a cascading effect of a decrease in biodiversity, increased disastrous wildfire risk, impacts to soil and water health, and a decreased resilience to climate change.
Back to the Plants
These are mountain azalea (Rhododendron canescens), the most common native azalea in the southeast US. These smelled amazing.
We initially identified this fungus as witch’s butter (Tremella mesenterica), but some people on iNaturalist (who generally specialize in what they’re identifying and are a lot smarter than me) identified it as orange jelly spot (Dacrymyces chrysospermus).
After some research, I found that T. mesenterica usually grows on hardwoods, and this was a soft pine, where D. chrysospermus does grow. Further research found that another common name for orange jelly spot is orange witch’s butter, which thoroughly confused me and made me start all over. Fungi identification is hard, and scientific names are important.
Speaking of fungi (kind of)5, I found this Christmas lichen fascinating. These lichens are excellent indicators of air quality. Their vulnerability to pollution makes their disappearance an early warning sign of harmful environmental conditions. They very definitely favored the north side of these trees.
Here is a mayhaw flower. I have to admit, I’ve never seen the flower or the fruit, but I’ve seen the jelly for sale plenty of times at farmer’s markets.
A Bit o’ Fauna
This is a black swallowtail with malformed wings we found. We couldn’t decide if this was just post-emergent, physical damage or some sort of illness. My initial thought was OE (Ophryocystis elektroscirrha), since a friend of mine has recently been giving educational talks about this disease, but the others told me that OE only affects monarchs, queens and lesser wanderer butterflies. I probably need to go to one of Linda Auld’s talks.
Janna, our group leader for the day, posted an image of this butterfly in one of her groups on Facebook, and the general consensus was that this specimen may have over-wintered in its chrysalis, had just emerged, and that the wings were still wet/sticky and needed time to unfold completely. Julie wins the prize for the best guess.
This, I believe, is the cocoon of the polyphemus moth, the giant silk moth with two large, purplish eyespots on its two hindwings.
My one bird photo of the day, a yellow-bellied sapsucker. We heard plenty of birds but didn’t see very many. I guess most of our time we were looking down.
Did you ever notice a horizontal line of holes on a tree, about half an inch apart? Sometimes there are multiple lines of holes. These are called “sapwells” and are the result of a sapsucker feeding on the sweet sap of the tree and any insects it finds trapped in the sap. The tree should recover from minor damage, but excessive numbers of holes can allow entry of insects and decay fungi that can cause secondary damage to the tree. Stress from intensive feeding can lead to cambium girdling, decline in tree health, and eventual death of the tree.
6 Master Naturalists and 1 Almost There
We had a great day exploring Crosby Arboretum and found so many, many more things than I had room for here. We’ll definitely be back.
Misidentifications are possible, even likely. I’m not an expert on everything in nature, but I do try to research new things and try my best to correctly identify what I see.
I’m in no hurry to try this one.
She hasn’t actually tried it yet. We have no idea if it’s disgusting or not.
The word "loblolly" is a combination of "lob", referring to thick, heavy bubbling of cooking porridge, and "lolly", an old British dialect word for "broth, soup, or any other food boiled in a pot". In the southern United States, the word is used to mean "a mudhole; a mire," a sense derived from an allusion to the consistency of porridge. Hence, the pine is named as it is generally found in lowlands and swampy areas. Loblolly pines grow well in acidic clay soil, which is common throughout the South, thus are often found in large stands in rural places. I am just a fountain of useless knowledge.
Lichens are bizarre organisms and no two are alike. Lichens are a complex life form that is a symbiotic partnership of two separate organisms, a fungus and an alga. The dominant partner is the fungus, which gives the lichen the majority of its characteristics, from its thallus shape to its fruiting bodies.
Sounds like you had a fabulous day! Makes me eager to get back outside and explore my own territory, but the weather up here has not been favorable. Have to wait a little while longer.