Archive for the ‘botany’ Category

6 Selected Plants that Grow in my Yard

August 3, 2022

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, a non-native species related to the coffee plant.

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.

Buttonweed, also a non-native species related to the coffee plant.

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.

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 is very abundant in my yard.
Bumble bee on golden cottony aster bloom.

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 big colony of evening primrose grows in my yard next to the road.

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 on sight. Nevertheless, I can’t get rid of them.

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.

Selected Plants from Jekyll Island

June 15, 2022

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.

Seaside oxeye. This plant was blooming in abundance in the dry areas adjacent to salt marshes in mid-May on Jekyll Island.

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.

The dominant grass species growing in salt marshes along the southeastern Atlantic coast is Spartina patens. Note the dead trees. This spot is located just behind Driftwood Beach where saltwater intrusion is killing a maritime forest.

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.

Saw palmetto next to a tree killed by salt water intrusion.
Live oaks here are being killed by saltwater intrusion here.

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.

Lantana camara. This is a non-native species found on Jekyll Island.

The Eastern Asian-Eastern North American Floristic Disjunction

January 27, 2022

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.

Forests and woodlands in this part of Asia are very similar to those of eastern North America. Image from Harvard University.
North American pachysandra next to a patch of Asian pachysandra. Photo by Peter Del Tredici.
550 year old Japanese Oak located in Korea. Eastern Asia is dominated by forests of oak like much of eastern North America.
North American trumpet honeysuckle.
Japanese honeysuckle is probably more common now in America than trumpet honeysuckle. The latter is prettier.

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

A Biblical Fruit Orchard in Georgia?

December 31, 2021

I covered lots of ground when I used to work for the Augusta Chronicle circulation department, collecting, soliciting, delivering papers, and handling customer complaints. I often saw wildlife while driving during the wee hours of the morning, and I came across interesting plants people grew in their yards. I was surprised to find a fruiting pomegranate tree on 1 occasion. I now know pomegranate trees can grow locally, but I didn’t think of planting them in my yard until my wife’s friend brought some over from her brother’s fruit orchard. This inspired me to plant pomegranates from seeds. Online sources claim the seeds germinate easily and produce good quality fruit in just 3 years. So far, the seeds haven’t germinated, but I am considering planting an orchard consisting of all the fruits mentioned in the bible. I think it would be an interesting showcase. The bible mentions at least 230 species of plants, including 9 kinds of fruits and nuts.

The bible mentions pomegranate 23 times in the Old Testament and 3 times in the Koran. Pomegranates have been cultivated for 5000 years, and Spanish settlers brought them to southeastern North America about 500 years ago, and they are still found in people’s yards. I am aware of 1 experimental pomegranate orchard near Alma, Georgia. George Wade, the farmer who maintains this orchard, says he removes and replaces trees that don’t produce at least 50 pounds of pomegranates. Pomegranates are hardy and can survive temperatures as low as 12 degrees F. A bigger problem is the summer humidity that causes blemishes. The fruit is still good to eat, but farmers can’t sell blemished fruit at the market.

My proposed biblical fruit orchard is halfway begun because I have been growing grapes and figs for decades. Grapes are mentioned 72 times in the Old Testament, 6 times in the New Testament, and 12 times in the Koran–more than any other fruit. Grapes have been cultivated for thousands of years and are native to North America.

Figs are mentioned 37 times in the Old Testament, 13 times in the New Testament, and once in the Koran. Adam and Eve sewed fig leaves together when they discovered their nakedness. Figs are 1 of the oldest cultivated plants, and there is archaeological evidence of figs in a human household, dating to 11,400 years BP (during the late Pleistocene).

Olives are the 2nd most common fruit mentioned in the bible. They are mentioned 49 times in the Old Testament, 12 times in the New Testament, and 6 times in the Koran. Olives are grown, albeit on a small scale, in Georgia. Blueberry farms are abundant in Georgia, and the surplus fruit depresses prices. Blueberry farmers are switching to olives because the same machinery can be used to harvest both. Olives can survive temperatures as low as 17 degrees F. It has been many years since it has gotten that cold at my house. Olives have also been cultivated for thousands of years. Remarkably, people learned to make the toxic fruit edible by soaking the olives in salt water and fermenting them.

I already grow the most common fruit mentioned in the bible–grapes. My grape vines are over 30 years old.
I also already grow figs, but I am having trouble getting a productive bush re-established.
This is an experimental pomegranate orchard near Alma, Georgia. Photo from youtube,
This is an olive orchard in Glennville, Georgia just west of Savannah. Virgin olive oil processed in Georgia costs $35 for 500 ml.

Dates are the 3rd most mentioned fruit in the bible. They are mentioned 34 times in the Old Testament, 8 times in the New Testament, and 22 times in the Koran. This is the only biblical fruit I probably won’t have success with. They can’t survive temperatures below 32 degrees F, and they won’t produce fruit in humid climates. However, I may be able to substitute jujubes, also known as Chinese dates or red dates. Jujubes are not true dates. Real dates grow on palm trees in hot dry deserts. Jujubes are large shade trees able to survive in a wide range of climates. Jujubes are possibly referred to in the bible twice. Scholars think the parable of the trees in Judges refers to the jujube, and they think the crown of thorns Jesus was forced to wear was made from jujube branches. Jujubes taste like dried apples.

Almonds are mentioned 10 times in the Old Testament. My late grandparents successfully grew almonds in Winder, Georgia. However, I am sure I would have the same problems with almonds as I do with my peaches. Almonds and peaches are closely related, and I have trouble with plum curculio infestations and fungus rot on my peaches.

Apples may be mentioned 5 times in the Old Testament, but scholars aren’t sure of the Old Hebrew world tuppuah. It may refer to citron instead.

Reference:

Jannick, Jules

“Fruits of the Bible”

Horticultural Science 42 (7) August 2007

Yellow Autumn Wildflowers in my Neighborhood

October 10, 2020

My neighborhood is on the top of a fall line hill in a sandy soil zone. The sandy substrate originated during the Eocene (55 million – 33 million years ago) when this region was a sea shore. It is a narrow zone found across 6 states, and it borders the oak-hickory-pine forest to the north and the open pine savannah zone to the south. The original dominant trees in this zone were sand laurel oak and longleaf pine, but the latter has been replaced by loblolly pine which is faster growing and less dependent upon frequent fire. Before European settlement the region was subject to periodic grass fires that thermally pruned the open woodland. Today, fire suppression results in thick growths of oak saplings on vacant lots. The original environment likely consisted of widely spaced pine and oak with an abundance of herb and grass species growing in the sunny undergrowth. The name of my road is “Piney Grove,” indicating what this area looked like about 50 years ago when the road was first paved.

This time of year 3 common yellow flowers bloom in my neighborhood, and there were probably acres of them here before it was subdivided into lots and landscaped with non-native turf grasses. Cottony goldenaster (Chrysopsis gossypinus) is a tough plant well adapted for growing in hot sunny conditions with sandy soils. I assume the name is based on the appearance of the bud before the flower blooms–it resembles an unopened cotton ball. I could find just 1 scientific study of this plant, and it focuses on anatomical distinctions between this and similar species. I’ve noticed 1 species of bee, 1 species of butterfly, and a small hornet, pollinating this perennial. This species has probably occurred in this region for millions of years because it has had similar climate and soil for ages.

I have a natural patch of cottony goldenaster in my yard. I don’t have to spend money on flowers.

Common sulphur butterfly (Colias philodice) pollinating a cottony goldenaster flower. The fall brood of this butterfly is greenish-yellow and they look like a leaf. They feed upon clover during their larval stage.

I don’t know what species of bee this is. But it is also pollinating a cottony goldenaster.

Sticktights (Bidens sp.), also known as beggar-ticks, produce a zoochorus fruit. The fruit sticks to fur, feathers, and clothing, and the seeds are spread throughout the environment in this way. It’s impossible for a deer, fox, or human to walk through a field and not inadvertently collect many of these fruits. 150-200 species of sticktights exist.

Fruit of the sticktight. These fruits stay on the plant after it dies and this increases the chances for the seeds to be spread by passing animals.

There are even more species of hawkweeds (Hieraciums sp.). Botanists count over 10,0000 species of hawkweed. I think the species in my neighborhood is field hawkweed (H. aespotosum), but I am no botanical expert and I don’t even know of a source with all 10,000 species illustrated, described, and compared.

Hawkweed.

Pleistocene Aspirin

December 27, 2019

The oldest human civilizations used plants high in salicylic acid to reduce pain and inflammation.  If the Sumerians were aware of these beneficial plant extracts 4500 years ago, it seems likely some individuals ancestral to them enjoyed this knowledge as far back as the Pleistocene.  I hypothesize this knowledge was lost and re-discovered countless times during the pre-history of man.  I’m sure people got sick and even died experimenting with the nutritional and mechanical benefits of various plants.

Salicylic acid is found in willow bark, meadowsweet ( Filipendula ulmaria ), myrtle, and numerous other plants.  Many different species of willow are found in the northern hemisphere, and they are common alongside streams and within wetlands.  Black willow ( Salix nigra ) is an abundant tree in eastern North America, but about 100 species of shrubs in the willow family occur across the continent.  They are all well adapted for living alongside streams.  Broken willow twigs floating down a stream can take root after becoming lodged in moist ground, giving them an additional mechanism for distribution.  Willow pollen is often found in sediment dating to the Pleistocene age, so it has long been found throughout the environment.  Ancient people made a tea from willow bark to relieve headaches and fever.  However, they couldn’t control the dosage, and pure salicylic acid irritates the stomach.

Black Willow Tree is the most significant willow species in the world. The black willow tree referred to as Salix nigra, swamp willow, or weeping willow; The tree found near wetlands in eastern parts of the United States; The average tree grows at the height of 50 to 65 feet tall.

Black willow tree.

Meadowsweet (Latin name Filipendula ulmaria). Medicinal plant in the natural environment of growth, Russia,Siberia Stock Photo - 67570243

Meadowsweet is also high in salicylic acid.

During the 18th century, the age of reason, chemists began experimental trials using salicylic acid.  In 1838 salicylic acid was first isolated from the extract of meadowsweet.  The first clinical trial of salicylic acid extracted from meadowsweet took place in 1876.  Felix Huffman, working for Bayer pharmaceutical company, invented modern day aspirin when he combined salicylic acid with an acetyl compound, creating acetylsalicylic acid. He had been treating his father’s arthritis with a sodium and salicylic acid compound that severely upset his dad’s stomach.  The aspirin was easier on his dad’s stomach.  Bayer started selling aspirin in 1899, and people no longer had to weigh whether getting rid of an headache was worth getting an upset stomach.  The drug was widely available by 1915, and when the world was at war with Germany, non-German companies started producing it.  There was no competition for aspirin until Tylenol went on sale in 1956, followed by ibuprofen in 1962.  Nevertheless, sales of aspirin remain strong, especially since doctors began prescribing a daily low dose of it for people with an high risk of an heart attack.

 

Pleistocene Watermelon (Citrullus lanatus)

August 3, 2019

During July and August I always have watermelon in my refrigerator.  After I run 3.3 miles in 95 degree F heat, nothing quenches my thirst better than a crisp cold slice of watermelon.  Primitive people living in the deserts of North Africa ~5000 years ago discovered the same usefulness of this species, but the story of the watermelon began long before that.

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Wild citron melons in South Africa.  They are a different species than the sweet watermelon we commonly know, but the type specimen (the first described by biologists during the 18th century) of Citrullus lanatus was mistakenly described from a specimen of this species, C. caffer.  Scientists didn’t discover this mistake until a DNA test of the museum specimen was conducted a few years ago.

A recent study of watermelon genetics estimated the citrullus genus (which includes all watermelons) first diverged from the rest of the Cucurbitidae family about 11 million years ago.  This family also includes bottle gourds, squash, and many other plants. There are 6 species of watermelon, and they originally occurred in Africa.  A single species of the 6 spread to India and Australia during pre-history, and man may or may not have been a factor in the distribution of this species.  The sweet watermelon (Citrullus lanatus) diverged from a sister species within this genus about 3 million years ago.  All members of the Citrullus genus are desert vines that survive arid conditions, but thrive and produce heavy yields following occasional downpours.  The abundant seeds are consumed by megafauna such as elephants and rhinos and spread across the landscape in their dung.  Today, elephants often destroy grain crops interplanted with cultivated watermelons when they seek out this delicacy.

The oldest known remains of sweet watermelons were found at a 5,000 year old settlement in Libya.  Harry Paris believes desert people in North Africa began cultivating watermelons as a portable source of water, rather than as a food source, though the seeds are edible and nutritious.  The first watermelons were green-fleshed, watery, and bland or even bitter.  Early farmers selected for sweeter fruit, and the gene for red flesh is paired with an increased sugar content.  Soon ancient mariners started carrying watermelons on their ships as a source of potable water and spread them throughout the warmer parts of the world.  Christopher Columbus brought watermelons to North America in 1493, and the Indians planted them everywhere they would grow.  William Bartram enjoyed a feast of oranges and watermelons when he visited Florida in the fall of 1775.

There are over 1200 varieties of cultivated watermelon.  I’ve successfully grown 2–Georgia Rattlesnake and Florida Black Diamond.  I used to pull out all the stops using fertilizer and special mulching tarp and was able to grow 35 pounders.  This year I bought a cheap $1.50 pack of Congo watermelon seeds and put minimal effort into the project and was justifiably rewarded with zero melons.

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Georgia Rattlesnake.  I successfully grew 35 pounders years ago.

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Black Diamond.  I successfully grew these 1 year too.

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My late grandfather grew Crimson Sweet watermelons.

Among the more interesting varieties of watermelon are the Carolina Cross and the Christmas King.  The Carolina Cross was bred for its prodigious size and holds the record for biggest watermelon ever grown at 351 pounds.  This could be served at baseball games and fairs.  The Christmas King is less sweet than most watermelons but if kept in a cold place will still be edible in late December.  How is that for an extended season?

Most watermelons sold in supermarkets today are seedless–a recent development.  Farmers began growing seedless watermelons during the 1990’s.  To make a seedless watermelon farmers chemically induce a change in the chromosome number in 1 of the parents.  When they backcross the 2 melons with different chromosome numbers it results in a seedless (or sterile) offspring in the same way crossing a horse with a donkey results in a sterile mule.  Modern seedless watermelons are of consistent quality and are just as sweet, crisp, and aromatic as the old time varieties.

Watermelons are mostly sugar water, but they do contain Vitamin C, a type of beta-carotene known as lycopene, and potassium.

The muskmelon (Cucomis melo) is not closely related to the watermelon but shares a common history.  It also was originally cultivated in the North African desert as a portable source of water.  Later, famers over many generations improved the quality of the fruit by selecting the sweeter individuals for seed.  Most people call muskmelons “cantaloupe.”  However, cantaloupe specifically refers to just 1 variety of muskmelon first cultivated in Western France.

References:

Chomicki, G.; and S. Renner

“Watermelon Origins Solved with Molecular Phylogenetics including Linnean Material: another example of Museomics”

New Phytologist Trust October 2014

Paris, Harry

“Origin of the Dessert Watermelon, Citrullus lanatus

Acta Horticulture March 2017

Pleistocene Mimosas

July 6, 2019

A remnant of the local original landscape grows on a 4′ by 4′ area of my front yard near the road.  It is known as sensitive briar (Mimosa microphilia), and it attracts numerous bees and other pollinators.  Sensitive briar resembles its close relative, sunshine mimosa (M. strigillosa), but differs in that its vine is covered with thorns.  These mimosas, native to southeastern North America, prefer to grow in prairies, ravines, savannahs, and open woods; and they do well on sandy or rocky soils.  I live in a sandhill area located on the fall line between the piedmont and the coastal plain.  The sandy soils originated during the Eocene when this region was a coast line and the fall line was a sandy beach.  Today, the co-dominant trees are loblolly pine and sand laurel oak.  Before humans repressed fires, it seems likely this area was dominated by longleaf pine with some sand laurel oak.  Longleaf pine is slow-growing and dependent upon fire for germination, and it has largely been replaced in my neighborhood by faster growing, less fire-dependent loblolly pine.  Also in the absence of fire, sand laurel oak forms dense stands on vacant lots when formerly they would be thermally pruned and grow farther apart.  I hypothesize the original environment was open woodland or even savannah, dominated by the aforementioned trees and with a great variety of flowers and grasses growing in the open spaces between the trees.  Other species in my neighborhood that might be remnants of this original environment include yellow cottony aster, a type of small daisy, prickly pear, ground cherry, blackberry, lowbush blueberry, false foxglove, and passion flower.

Sensitive briar growing in my front yard by the road.

The mimosa genus includes about 400 species of herbs, shrubs and trees within the legume family.  The most commonly noticed mimosa in southeastern North America is Albizia julibrisson,  a native from Asia and the Middle East.  It was introduced to Charleston, South Carolina in 1783 and has spread like crazy all across the region.  They are found in open areas alongside roads and are now considered an invasive species.  I think they are more beneficial than detrimental.  Their flowers feed the bees and butterflies, and their roots, like those of all legumes, help fix nitrogen in the soil.  They are probably more beneficial than many of the native plants they outcompete.  They produce numerous bean pods that readily germinate in road side ditches.

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Mimosa trees are widespread and common in disturbed areas of the southeastern United States.

The mimosa genus is very old with a world wide distribution.  They likely originated before the continents drifted apart.  During the Pleistocene sensitive briar flourished in the open spaces that resulted from rapid climate change and megafauna foraging.  However, there is no pollen or fossil evidence of this species from that age.  Nevertheless, I’m sure they were common in some areas and just perchance left little evidence of their previous existence.

Plants in the mimosa genus are capable of rapid movement.  Sensitive briar closes its leaves when being touched.  Scientists think this response helps protect them from foraging herbivores, but they are vulnerable to at least 1 predator–the mimosa webworm (Homodaula anisocentra).  The larva of this species wraps mimosa leaves inside a protective webbing which prevents the leaves from closing completely.  They then feed upon the leaves before their transformation into their adult stage.

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Mimosa webworm.

Pleistocene Mulberries (Morus sp.)

April 28, 2019

Ordering fruit trees from a catalogue or internet site is a dodgy endeavor.  The trees are overpriced with an added cost of shipping, and in my experience I’ve learned the trees produce poor quality fruit, if they even survive long enough to bear.  I’ve had much better luck transplanting trees from local nurseries.  I have 26 year old grape vines and blueberry bushes almost as old that I purchased from local nurseries, and I’d still probably have a great fig tree, if plumbers didn’t have to dig a new drain field for my septic tank.  Peach trees I’ve grown from seed are much stronger and produce much better fruit than any I ever purchased through the mail.  A mulberry tree growing by the side of my house is an example of mail order disappointment.  The tree is thriving and flowers every spring but it produces no fruit.  This puzzled me until I finally figured out why.  The tree died back the first year I bought it, but it regrew from the stump.  Nurseries sell mulberry trees with male and female branches.  (Male flowers produce no fruit.)  Unfortunately, the part that grew back on my tree is all male.

Male flower on my mulberry tree.  Female flowers have a more round shape.  All the flowers on my mulberry are male, much to my disappointment.  Click to enlarge the photo.

Mulberries belong to an ancient family that has existed since at least the mid-Cretaceous, and dinosaurs likely dispersed the seeds of the fruit from this family in their feces.  The Moraceae family includes mulberries, figs, Osage orange, jack fruit, and bread fruit.  The species of native mulberry common and widespread in eastern North America is Morus rubra.  The range map of this species shows some affinity in its northern limit with the ghost boundary of the Laurentide Glacier.  (See https://markgelbart.wordpress.com/2017/03/30/the-ghost-boundary-of-the-last-glacial-maximum-ice-margin/ ) However, like many other species of trees M. rubra successfully recolonized some territory that became deglaciated following the last Ice Age.  It’s likely red mulberry grew in mixed forests all the way to the glacial boundary during Ice Ages but became much more common during warmer wetter interstadials and interglacials.  Mulberry trees prefer early to mid successional woodlands where they can get plenty of sunlight.  Hence, they are a pioneer species dispersed in bird droppings.  Disturbed plant communities caused by rapid climate change and megafauna foraging were common during the Pleistocene and so were mulberries, though their pollen is rarely detected in core samples.

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Range map of the red mulberry.  It has been widely transplanted outside its range.  Avian dispersal helped this species recolonize deglaciated regions following the end of the last Ice Age.

Birds love mulberries, and avian dispersal explains how mulberries recolonized deglaciated regions when so many other species did not.  A study of 1 backyard mulberry tree in Arkansas counted 32 species of birds feeding on the fruit.  Cedar waxwings and robins made up 77% of the individual birds visiting the tree.  Other birds feeding on the fruit from this tree included mockingbirds, finches, catbirds, eastern kingbirds, and warblers. The fruit appeals to bird species that normally prefer insects.

Mulberries were especially common around Indian villages during Colonial times and earlier.  William Bartram mentioned M. rubra  at least 20 times in his Travels. Mulberries ripen over a 3 week period during late May and early June and were an important earl summer fruit for the Indians.  They can be dried and dried mulberries are a staple in Afghanistan.  European settlers brought white mulberries (M. alba) to North America, hoping to start a silk industry.  For 4 thousand years the Chinese have been raising the silk worm moth (Bombyx mora), a species no longer found in the wild.  The silk worm moth larva feed upon mulberry leaves and produce silk for their cocoon.  The silk industry collapsed in North America long ago and now they grow wild, often hybridizing with native mulberries.

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Silkworm moth larva feeding on mulberry leaves.

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Red mulberry fruit.  Despite the name, they aren’t ripe until they turn black.

Mulberries are very sweet and nutritious.  They are high in Vitamin C and iron and also a good source of potassium, Vitamin K, Vitamin E, and fiber.  They are rich in cholesterol-reducing and cancer-fighting anti-oxidants.  They make good desserts as well, but they do have 1 drawback.  The stem grows well into the fruit and is difficult to remove.

Reference:

Jackson, J; and R. Kanin

“Avian Frugivory in a Fruiting Mulberry Tree (Morus rubra) in Arkansas”

Journal of Arkansas Academy of Science 2016

Piedmont Plant Species Bartram First Encountered at the Augusta Shoals

July 22, 2018

I’ve read all or parts of Bartram’s Travels hundreds of times, but whenever I re-read it I always find something new that fascinates me.  William Bartram journeyed from Savannah, Georgia to Augusta during 1773, and in his book he describes the flora of the maritime forests, lower coastal plain, and upper coastal plain.  The descriptions are so packed with information I didn’t notice until recently a small paragraph about some piedmont plant species he first encountered alongside the shoals of Augusta.  He refers to this spot as a cataracts.  Several important Indian trails converged here because the shoals afforded a shallow crossing.  Augusta developed as an Indian trading village because of these shoals.  Bartram describes Augusta as a small village that reaches all the way to the “cataracts,” and it was surrounded by “gay lawns and green meadows.”  Augusta is on the edge of the hill country, and species that prefer higher elevations begin to occur here.  Bartram arrived in May when all of these species were in full bloom.  He listed Rhododendron ferruginumPhiladelphus inodorus, Malva, and Pancratium fluitans.   I haven’t visited the shoals in a while, but I don’t recall seeing any of these species next to the shoals.  They’ve been eliminated from the immediate vicinity, though the first 3 are commonly planted as ornamentals in people’s yards.  Bartram wrote Pancratium fluitans inhabited every rocky islet on the shoals.  (The common name of this species is rocky shoals spider lily.  It’s modern scientific name has been changed to Hymenocallis coronaria.)  Unfortunately, today there are just 50 populations of this species left because reservoirs inundate their favored habitat.  The natural beauty of rocky shoals has diminished since Bartam saw them.

Scenes around Augusta, Georgia - Savannah River shoals - Stock Image

Augusta shoals.  The lock was built 100 years after Bartram saw it.

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Rhododendron ferrugineum is a common ornamental plant in Augusta.  It grew wild near the Augusta shoals.

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Scentless mockorange is also commonly planted as an ornamental but wild populations grew near the shoals.

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Common mallow is a non native species that was already widespread in Augusta by 1773.  This is probably the Malva species Bartram mentions.  There is a native species of mallow–Carolina mallow (Modiola caroliniana), however Bartram described the mallow he saw as blue, and this is the wrong color for Carolina mallow.

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Rocky Shoals spider lily.  Only 50 populations of this species still exist.  Most have been wiped out by reservoir creation.  In Bartram’s day they inhabited every rocky islet on the Augusta shoals.