GeorgiaBeforePeople

Sumac is a common shrub found throughout eastern North America where it thrives in old fields and roadsides because it prefers sunny locations. The red berries ripen in late September here in Augusta, Georgia, and I often make a pleasantly acid tea with them. Malic acid, the same substance that makes apples tart, is what gives sumac berries a sour taste. To make the tea, steep the berries in hot water for about an hour. Don’t refrigerate the tea, or the sour taste will become bitter. The berries are also used as a seasoning in Middle Eastern cuisine.

There are 29 species of sumac in North America, 1 in western Asia and Europe, 1 in Hawaii, and 4 in eastern Asia. This is evidence sumac originated in North America. Genetic evidence suggests sumac spread across the Bering land bridge to Eurasia 33 million years ago. Birds spread sumac seeds by consuming the fruit and depositing the still viable seeds in their droppings. I’ve witnessed cardinals and mockingbirds eating sumac berries. Sumac also spreads through their underground roots.

Staghorn sumac. It is easily distinguished from poison sumac.

Poison sumac (Toxicodendron vernix) looks nothing like true sumac. It is a species of poison ivy.

Sumac has been common in North America since the Eocene.

Poison sumac (Toxicodendron vernix) is not a true sumac but instead is a species of poison ivy. It is easy to distinguish between poison sumac and true edible sumac. True sumac produces seed clusters that stand up, like an erection. Poison sumac berries droop.

Sumac is a member of the cashew family (Anacardiacaea). Sumac’s closest relatives are poison ivy and pistachio. Sumac diverged from their closest relatives about 49 million years ago. Within the sumac genus (Rhus) there was a divergence between 2 subgroups (Lobelia and Rhus) about 33 million years ago. Some of the better known species of sumac include 3 leaf sumac (R. trilobata), staghorn sumac (R. typhina), and smooth sumac (R. glabra). Dwarf sumac (R. michauxii) is considered endangered and is only known from 1 site in Georgia, 1 site in North Carolina, and 1 site in Virginia. Most species grow from 3-33 feet high.

Genetic evidence suggests sumac has been a common plant since the Eocene. The open conditions that prevailed during Ice Ages likely favored the development of sumac patches then.

References:

Burke, J., and J.C. Hamrish

“Genetic Variation and Evidence of Hybridization in the Genus Rhus (Anacardiaceae)

Journal of Heredity 2002

Huang. L., et al

“Three complete Chloroplast genomes from the North American Rhus Species, Phylogenome of Anacardiaceae”

BMC Genome Data March 2025

Eastern cottonwood trees rapidly grow to an enormous size. They reach heights of over 100 feet tall with diameters over 9 feet thick. The U.S. national champion in Beatrice, Nebraska is 89 feet tall and has a canopy 108 feet wide. The largest cottonwood in the world was planted in New Zealand circa 1870 where it is not native, and it is 138 feet tall and has a canopy 34 meters wide. Normally, cottonwoods live for 70-100 years, but they can live for 400 years. The Balmville Tree in New York was 316 years old before it was felled.

Photo of the largest known cottonwood tree in North America.

This is the largest known cottonwood tree in Georgia.

A grove of cottonwood trees in Arkansas.

Leaves and seeds of cottonwood.

Cottonwood trees depend upon flooding rivers for their existence. Floods wash away competing vegetation, leaving bare soil where cottonwood seeds can germinate. They are a shade intolerant species as well, and repeated floods thin the surrounding vegetation. This dependency explains why cottonwoods are so common on western river bottomlands. They have less competition alongside rivers that snake through prairies. Wind carries cottonwood seeds and pollen great distances, and they readily colonize bottomlands following scouring floods. Cottonwood trees are also commonly found in the east, but they particularly thrived during Ice Ages when grasslands prevailed over woodlands. There isn’t much fossil evidence of cottonwood trees dating to the Pleistocene, and their pollen barely shows up on pollen graphs, but fossil cottonwood leaves have been found in the Rita Blanca site in Texas alongside leaves from oak and willow. Cottonwoods are in the same family as willows, another tree that prefers wetlands. The Rita Blanca site in Texas was formerly a lake during the early Pleistocene.

Big tooth aspen (P. grandidenta), a related species, occurs north of the Last Glacial Maximum boundary. This species colonized New England within the last 10,000 years. It must have occurred further south during Ice Ages. It co-occurs in some parts of its range with the closely related quaking aspen (P. tremuloides), but they don’t hybridize in the wild because they flower at different times. Plant breeders have managed to hybridize them in cultivation.

Cottonwood trees are grown commercially for paper pulp. Their rapid rate of growth is an economic benefit. The wood is also used to make boxes.

The tradition of giving roses to mom on Mother’s Day is recent, but the Rosa genus is ancient. Fossil evidence of roses dates back to the Eocene over 33 million years ago. Genetic evidence suggests roses are closely related to strawberries (Fragaria sp.) and blackberries (Rubra sp.), and the 3 diverged about the same time. There are 360 species of roses, and they occur across Eurasia and North America. Cultivation of roses began in China during the 1700s. Today, there are thousands of varieties. The genetic study (referenced below) determined the modern cultivated rose is a hybrid between the Chinese rose (Rosa chinaensis), and various European species of roses. The former has the desirable characteristic of repeated blooming, while the latter grow more vigorously.

Many people mistakenly think roses they find at abandoned homes sites or in the woods are native. Most are probably cultivated roses that have persisted because they are long-lived. However, there are at least 2 species of wild roses that are native to southeastern North America. The Carolina rose (Rosa carolina) prefers dry prairie openings within eastern forests, and they thrive on dry sandy sites. The swamp rose (Rosa palustris) grows on wet ground in swamps and marshes and can tolerate more shade. The abundance of each during the Pleistocene likely varied during different climate fluctuations.

The swamp rose is a native species of rose. It can tolerate some shade and prefers moist conditions.

Rose hips are edible. They taste like apples.

Roses produce an edible fruit known as a hip. They supposedly have more Vitamin C than an orange. The hips I’ve eaten taste like apples. Birds also like to eat the hips, and wild roses, like so many other berry-producing species, depend on birds for dispersal, though some seed-eating birds eat and digest the seeds and don’t aid dispersal. Most cultivated roses don’t produce hips because they are bred to have tightly clustered flowers that prevent pollination.

Reference:

Raymond, O; et al.

“The Rose Genome Provides New Insights into the Cultivation of Modern Roses”

Native Genetics 50 2018

I’ve come across anecdotal evidence, suggesting hackberry trees were locally abundant during Ice Ages. Today, hackberry is a minor component of deciduous forests. I know of 3 sites dating to the Pleistocene where the remains of hackberry have been found. Plant remains dating to the Pleistocene are relatively rare, so the occurrence of this species might be significant and not just a coincidence. Hackberry seeds were found associated with the skeletons of a flat-headed peccary herd that was buried by a sandstorm in western Kentucky thousands of years ago. (See: https://markgelbart.wordpress.com/2013/03/10/when-sand-dunes-buried-herds-of-flat-headed-peccaries/ ) Hackberry along with oak were the most abundant plant remains and DNA dating to the Pleistocene found in Hall’s Cave located on the Edward’s Plateau in Texas. (See: https://markgelbart.wordpress.com/2020/06/29/new-study-of-the-seda-dna-in-halls-cave-texas/ ) Hackberry trees are still common near the cave entrance. And hackberry leaves were found in Kingston Saltpeter Cave in North Georgia, though it’s unclear if the leaves were actually in the layer with the Pleistocene animal remains.

I hypothesize there were 3 factors why hackberry thrived when other deciduous species declined in abundance during Ice Ages. Foresters note Georgia hackberry grows well on dry rocky sites. The Ice Ages were arid because much of earth’s water became locked in glacial ice, and dry environments prevailed in many locations. Perhaps hackberry was better able than other hardwood trees to endure the lower atmospheric CO2 levels that occurred during Ice Ages. Hackberry also may not have been a preferred food of the megafauna. So, when megafauna consumed other plants, they were eliminating competition for sunlight and growing space. Though this is just speculation and probably impossible to determine because evidence has eroded away, I envision groves of widely spaced oak and hackberry trees growing with bunch grass and bare soil between the trees in dry environments across the piedmont region of southeastern North America during Ice Ages. Pollen records suggest pine was more abundant than hardwoods during Ice Ages, but pine produces much more pollen than hackberry and may be overrepresented by comparison. Hackberry pollen rarely shows up in pollen records. However, there are very few (if any) local pollen records from this region dating to the Last Glacial Maximum, and pollen records are not always all inclusive.

Hackberry trees belong to the Celtis genus and were formerly thought to be in the same family as elm, but modern botanists recently decided the Celtis genus belongs in the Cannabis family. This means they are related to hemp and marijuana. There are 66 species in the Celtis genus worldwide, and they are found in the Northern Hemisphere, South America, and central Africa. 3 species live in eastern North America–common hackberry (Celtis occidentalis), Georgia hackberry also known as dwarf hackberry (C. tenuifolia), and sugarberry (C. laevigata). Common hackberry’s continuous range is just north of Georgia, but disjunct populations do occur in the state. Georgia hackberry is found in the piedmont region of southeastern North America, plus southern Missouri and parts of Appalachia, Louisiana, and Texas. Sugarberry is found throughout the southeast.

Range map for Georgia hackberry, also known as dwarf hackberry. It prefers dry rocky piedmont soils.

Range map for sugarberry.

Georgia hackberry. It is usually a medium sized tree.

Georgia hackberry leaves.

Hackberry fruit is edible. I’ve tasted the fruit of Georgia hackberry, and it’s bittersweet and mostly skin and seed. Sugarberry looks bigger and may have more flesh. American Indians pounded the fruit, seed and all, into pemmican–a mixture of berries, jerky, and meat fat. Many species of brush-footed butterflies feed upon hackberry leaves during their caterpillar stage. The fruit stays on the tree all winter and provides food for birds.

Hackberry emperor butterfly larva like to feed upon hackberry leaves. Other caterpillars in the brush-footed butterfly family also feed upon hackberry leaves.

Sugarberry fruit. I have never eaten sugarberries, but I have tasted Georgia hackberries. They are more skin and seed than fruit, and they taste bittersweet. These look fleshier. Native Americans pounded the fruit into pemmican.

I have a hard time finding oranges, particularly tangerines, that have any flavor. Tangerines, also known as Mandarin oranges, used to have delicious flavor and aroma, but modern farmers developed seedless varieties that are easy to peel and eat and have a long shelf life. They taste so bland; I regret purchasing them every time. “Little Cuties,” small seedless Mandarin oranges, are heavily marketed and found in all grocery stores, but they are usually a tasteless disappointment. Other modern Mandarin orange varieties are just as bland. My favorite variety of orange is the Temple orange. They are full of seeds but taste good. I haven’t been able to find them in several years. Not being able to get a good orange is just another annoyance I suppose I’ll have to learn to accept. Modern grapefruit varieties are an improvement, however. I remember when grapefruits needed added sugar, but it is not necessary to add sugar to the grapefruit varieties available today.

All citrus species originated in the Himalayan foothills during the late Miocene about 8 million years ago. They were first cultivated in China at least 1700 years ago and soon spread to India. Scientists aren’t sure how many species of citrus exist because men have been interbreeding them for so long. The Moors brought sour oranges (Citrus aurantium) to Spain and North Africa during the 8th century. Sweet oranges weren’t introduced to Europe until the 15th century. The Spanish brought oranges to Florida, and William Bartram saw large groves of wild oranges growing all over the territory by 1776. The Spanish also brought oranges to California. Today, the orange is the most widely grown fruit in the world. Leading producers of oranges include in order Brazil, China, India, the U.S., Mexico, and Spain.

Scientists recently mapped the genome of citrus fruits. The modern sweet orange is a hybrid between pummelo (C. maximus) hybrids and mandarin oranges (C. reticulata). Pummelos can be found in grocery stores and are similar to grapefruits but have thicker skins and more pith. Grapefruits are a back crossing of mandarin hybrids with pummelos. Mandarin oranges have been back crossed with pummelos several times. Lemons are a hybrid between sour oranges and citrons.

Reference:

Guohong, Albert; et. al.

“Genomics of the Origin and Evolution of Citrus”

Nature 554 Feb 2018

Walnuts first appear in the fossil record during the Eocene, 45 million years ago. Some scientists believe this is when walnut trees first began to diverge into different species, however, this belief is inconsistent with the results of a recent genetic study. Today, there are 21 species of walnuts, but the genetic evidence suggests they didn’t begin to diverge from a common ancestral species until about 1.5 million years ago. Some scientists believe 1 walnut species occurred from North America across the Bering Land Bridge through Eurasia before Ice Ages began. The genetic study (referenced below) determined species divergence began after Ice Age climate conditions isolated different populations of walnut trees. The authors of this study suggest the 15 known fossil species of walnuts, dating to before the Pleistocene, are actually just 1 species that lived in a multi-continent zone of equable forest. Another odd finding of this study determined there were no population declines in walnut populations during the Last Glacial Maximum when temperate forest zones were replaced in northern latitudes with boreal forest zones dominated by spruce. Also, plant diseases appear to be a greater or equal influence on walnut populations than climate.

The 21 species of walnuts all belong to the Juglans genus within the Juglandaceae family which also includes the hickories. The English walnut (Juglans regia) is the commercially grown walnut found in grocery stores. This species originated in Iran. Ice Ages caused the extirpation of walnut trees in most of Europe. Two species of walnuts are native to eastern North America–the black walnut (J. nigra) and the butternut (J. cinerea). The latter species is in serious decline due to a disease pathogen. Black walnut wood is prized by furniture makers, and the nuts are a little tastier than English walnuts. The shells are much harder to crack. I find it necessary to use a meat mallet on the hard floor…standard nutcrackers won’t work. Black walnuts are not grown commercially on a large scale, and most of the ones found in grocery stores are gathered from the wild. There are also different species of walnuts found in California, Texas, the West Indies, South America, China, and Japan.

Walnuts are an excellent source of nutrition. They are 14% carbohydrate, 15% protein, and 63% fat. The nuts are high in B vitamins, minerals, and the healthy kind of fat also found in salmon and other fatty fish.

Reference:

Bai, Wai-Ning; et. al.

“Demographically Idiosyncratic Responses to Climate change and Rapid Pleistocene Diversification of the Walnut Genu Juglans (Juglandaceae) Revealed by Whole Genome Sequences”

New Phytologist November 2017

I live on the beach, or rather it used to be a beach 33 million years ago. Now, this location is about 128 miles inland. Nevertheless, the soil is still sandy, and ecologists classify it as a piedmont sandhill. Plants able to grow in arid sandy conditions thrive here. The co-dominant trees are sand laurel oak and loblolly pine, though I think long leaf pine formerly prevailed. I believe this area was alternately part of the long leaf pine savanna region that before European colonization dominated the coastal plain. The name of the road I live on is “Piney Grove,” indicating its original appearance. It was likely subject to frequent light grass fires. The soil is particularly sandy compared to much of the coastal plain, however, and the local environment may have been quite unique. Cleared lots soon get covered in sand laurel oak saplings, persimmon, sumac, sassafras, prickly pear cactus, and low bush blueberry. Many interesting herbaceous plants grow here as well. I stopped using a lawn mower over 20 years ago and instead use a scythe to keep vegetation in check. I selectively cut my yard and allow interesting plants to form patches. Here are 6 interesting plants that find refuge in my yard.

Florida pusely (Richardia scabra) is native to South and Central America and Mexico and is also known as Mexican parsley, though it is related to coffee trees, not true clovers which are legumes. Most google results for this plant suggest how to get rid of it. Some people demand perfect lawns. I’d rather have the pusely. It produces pretty white flowers that attract bees and butterflies, and the foliage covers the ground. Reportedly, it is edible, but I wouldn’t try it because it is closely related to a species used to induce vomiting.

Next to a patch of Florida pusely is a patch of buttonweed (Hexasepalum teres), also known as poor joe. This species is also a native of South America and belongs in the coffee family. It has tiny blue flowers.

Trumpet vine (Campsis radicans) is a member of the Bignoniaceae family. Its flowers attract hummingbirds, but the rest of the plant is toxic to people and most animals. It is native to eastern North America and fairly abundant in my neighborhood.

Golden cottony aster (Chrysopsis gossypinus) grows on the edges of wooded areas and blooms from September to November. The flowers attract butterflies and bees, and it is so named because the flower buds resemble the buds on cotton plants before they bloom. It is a member of the aster family.

A long patch of evening primrose (Oenothern biennis) grows alongside the road on the front part of my yard amidst the Bahia grass. Every part of this plant is reportedly edible including the roots, leaves, and seeds. Evening primrose seed oil is thought to ease the symptoms of PMS, but pharmacological studies are so far inconclusive. Birds eat the seeds, and evening primrose is the host plant for 2 species of moth. Native-Americans used the plant as well. It blooms in June here, especially in the evening, hence the name. It is a member of the Onagraceae family and is found throughout North America.

I destroy sandspurs (Cenchrus sp.) as much as I can, but I can’t get rid of this tough plant. The hairs on this plant cause annoying itching when they come into contact with human skin, and the seeds are encased in burrs covered with sharp spines that attach themselves to animal fur or human socks and shoes. I’ve spent much time pulling dozens of them off my socks, getting them stuck in my fingers instead. They fall off in the carpet where my bare feet step on them too. The seeds of this plant are spread all over by animal transport. This genus is so successful they are native to 4 continents. Reportedly, the seeds are edible, but may be infected with the ergot fungus–the kind that causes LSD-like reactions.

I encountered some interesting plants during my recent visit of Jekyll Island. Seaside oxeye (Borrichia frutescens) was a first for me, and I needed online help identifying it. This species grows in abundance on dry areas surrounding salt marshes, and it was in bloom on the island during mid-May, a little earlier than at other parts of the Atlantic coast. It belongs to the Aster family and can live for 5 years, spreading vegetatively and via seeds. The flowers attract butterflies. Leafhoppers and aphids feed upon the plant. Gall midges and gall wasps also attack the plant as part of their lifecycles. Birds eat the seeds. Seaside oxeye is reportedly an edible plant for humans and can be eaten cooked or raw, but it doesn’t have good flavor.

Saltwater cordgrass (Spartina patens) is the dominant grass found in salt marshes along the North America south Atlantic coast. It is a keystone plant crucial to the health of this vital ecosystem. This plant helps maintain water quality and shelters many species of animals including diamondback terrapins, clapper rails, raccoons, otters, and fiddler crabs. Periwinkles graze on the grass to help keep it in check.

Saw palmetto (Serenoa repens) is the source of much quackery. Snake oil salesmen falsely claim extracts made from palmetto berries cure prostate problems. There is no scientific evidence for their phony claims. The palmetto berries are an edible fruit eaten by raccoons, bears, and Indians. Early European explorers were not impressed with the taste, however, and it was considered a desperation source of food. I’ve seen raccoon scat filled with palmetto berries. Saw palmetto is a scrub palm tree, and Indians used the palm fronds for fiber and roof thatching.

Common lantana (Lantana camara) was another first sighting for me. This species is native to Central and South America but has invaded warmer regions of North America, especially along the Atlantic coast. It is a member of the Verbena family, and its foliage is toxic to livestock. Lantana fruit, in particular the unripe berries, are highly toxic for humans, but birds relish them and spread the seeds in their droppings. This species is fire tolerant but shade intolerant and requires open landscapes to survive. The flowers come in 5 color varieties and attract butterflies and nectar feeding jumping spiders from the Salticidae family.

Botanists recognized the great similarity between the forests and woodlands of eastern Asia and those of eastern North America as early as the first decades of the 19th century. Asa Gray, a renowned botanist of that century, was the first scientist to quantify the similarity. He listed 538 plant species found in both regions. Later scientists realized these species were not the same, though they were similar and closely related. Based on paleontological evidence, scientists determined most of these similar species diverged during the late Miocene, following the uplifting of the Rocky Mountains. Throughout most of the Miocene, a warm temperate forest zone existed from eastern North America across the Bering land bridge and extending into Asia and Western Europe. The uplift of the Rocky Mountains and the Himalayas disrupted the widespread equable climate that supported this warm temperate zone of forest. Species that preferred temperate forests became restricted to areas of eastern Asia and eastern North America. After becoming isolated from common parent species that ranged across this Miocene forest, American species diverged from Asian species. A study of plant DNA from 22 similar species found in both regions supports the paleontological evidence. Most closely related species diverged between 10 million years ago to 5 million years ago. The oldest divergence took place 12 million years ago, and the youngest took place 3 million years ago.

Eastern North America has more plant species related to those of Eastern Asia than to those of Western North America, and Eastern Asia has more species related to those of Eastern North America than to those of Western Europe, despite the wider geographical separation. Both regions are richer in species than Western Europe and Western North America. Ice Age glaciations drove more species into extinction in those 2 regions. Eastern Asia has 33% more plant species than eastern North America. This suggests more abundant refugia from Ice Age glaciations, and it also points to Asia as the region where most genera and families originated.

Closely related species on both continents include many species of oaks, walnut, chestnut, buckeye, arrowwood viburnum, elder, magnolia, clematis, catalpa, honeysuckle, white pine, and cedar. Scientists have also found the same pattern of similarity with fungi, spiders, millipedes, and fish.

Reference:

Tiffney, B.

“Perspectives on the Origin of the Floristic Similarity between Eastern Asia and Eastern North America”

Journal of the Arnold Arboretum 66 1985

Xiang, Q., D. Soltis, P. Soltis, D. Crawford

“Timing the Eastern Asian-Eastern North American Floristic Disjunction: Molecular Clock Corroborates Paleontological Estimates”

Molecular Phylogenetic Evolution 325 (2) 2000