Collected on this day...
a weekly blog featuring specimens in the Carnegie Museum's herbarium.
each specimen has an important scientific and cultural story to tell.
each specimen has an important scientific and cultural story to tell.
Fa la la la la, la la la la
'Tis the season to be jolly.
Are you decking your halls with boughs of holly? This specimen of American holly (Ilex opaca) was collected by M.L. Bomhard in Mandeville, Louisiana by on December 8, 1928. The holly revered for its holiday cheer usually refers to a related European species, Ilex aquifolium. But there are native holly species in North America that are equally (if not more) cheerful. Like most other hollies, American holly is dioecious, meaning it has male and female flowers on separate plants. Only the female plants have the characteristic bright red berries we all know and love. American holly stands out as one of the few broadleaved evergreen trees native to the Eastern US (i.e., has green leaves during winter that are not needles). This species is near the northern edge of its range in Pennsylvania and is more common in southern states. It is listed in PA as a species of “special concern” due to its relative rarity.
Indiana, PA: Christmas Tree Capital of the World!
Around 25-30 million cut trees are sold each year in the United States for the holidays.
These Pennsylvania specimens shown above were collected sometime in December (exact day unknown): White Pine (Pinus strobus) in Kittanning in 1926 and Scots Pine (or “Scotch Pine”; Pinus sylvestris) from cultivation in Avalon in 1902. Both of these species are cultivated and used as decorative trees for the holidays. Many evergreen conifer species are cultivated in the US for decorative use during the holidays. Needle length, softness, retention, color, and even scent vary by species or variety. Similarly, branching patterns and branch strength differs. Plus, some species grow faster and easier than others, which means some species are cheaper.
Did you know that Pennsylvania is one of the top states for Christmas tree farms? In fact, southwestern PA’s very own Indiana County is known as the “Christmas Tree Capital of the World.” According to the Indiana County Christmas Tree Growers’ Association, the title arose in 1956, when an estimated 700,000 trees were cut that year in the county.
Believe it or not, there are no CM specimens from Indiana County collected in the month of December. This isn't all that surprising, as most specimens aren't collected in the winter.
Before farms began cultivating trees for that purpose in the early 20th century, people just went to the woods to cut down their tree for the holidays. Some of the earliest Christmas tree farms in the US started in Indiana County as early as 1918. Many farms in the region turned their fields into Christmas tree farms as it became profitable. By 1960, more than 1 million trees were harvested per year in Indiana County alone. The harvest in Pennsylvania has declined for several reasons, including increased popularity of artificial trees and consumer interest in Frasier fir trees (Abies fraseri; native to the Southern Appalachians and grows slower in PA than farms in North Carolina). However, Pennsylvania is still among the top five states in terms of both number of working Christmas tree farms and trees harvested. According to the National Christmas Tree Association, 31,577 acres in Pennsylvania are used as Christmas tree plantations. Many of the Christmas tree lots in southwestern PA get their trees from farms in Indiana county.
What you know as yams are most likely not really yams. In fact, your “classic” potatoes, sweet potatoes, and yams are all in different plant families. However, they all are widely cultivated for their nutritious starchy belowground plant structures called “tubers.” Tubers function as storage organs for the plants, providing energy for regrowth (the “eyes” or sprouting buds of your potatoes when they sit in your kitchen for too long). Potatoes and yams technically have modified belowground stems (“stem tubers”) while sweet potatoes have “root tubers.”
Yam is a common name for several vine species in the genus Dioscorea (plant family: Dioscoreaceae). They are monocots (related to grasses and lilies). Yams are widely cultivated worldwide, especially in West Africa, where 95% of the crop is harvested. Yams can be stored for very long periods of time, making them an important crop for seasons when food is in short supply. Yam tubers can be as large as five feet long!
Sweet potatoes refer to a vine species (Ipomoea batatas) in the morning glory family (Convolvulaceae). This species is likely what is on your Thanksgiving dinner table. In the United States and Canada, sweet potatoes are often (confusingly) referred to as “yams.” But sweet potatoes are not even closely related to yams. As such, the USDA requires any label with “yam” to also include “sweet potato.” So why are sweet potatoes sometimes confusingly called yams?! Well, this naming probably dates back to colonial times when slaves from Africa noted the similarities between some varieties of sweet potatoes to yams in Africa.
And last - the “classic” potato, Solanum tuberosum. Potatoes belong to the nightshade family (Solanaceace), which also includes many other important crops like peppers, tomatoes, tomatillos, eggplant, tobacco, and more. Critical to the world’s food supply, potatoes are the fourth most farmed crop. Potatoes are only distantly related to sweet potatoes. They are also called “spuds,” which probably originated centuries ago from a term for a spade used to dig holes to plant potatoes. Having been cultivated for centuries, there are thousands of potato varieties worldwide. The cultivated species was domesticated from wild relative potato species in South America (Peru) 7,000 – 10,000 years ago. Important discoveries on the origin of potatoes were based on DNA from 200 year old herbarium specimens! Similarly, the origin of the Irish Potato Famine (caused by potato late blight from a fungal pathogen) was also discovered using fungal DNA extracted from 160+ year old herbarium specimens!
For more on cool new Irish potato famine research: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0168381
For more on origins of European potato: https://www.ncbi.nlm.nih.gov/pubmed/21632349
Specimen above: "Yam" species (Dioscorea schimperiana) collected in 1960 by A.C. Twomey in Kenya. Yams are an important food crop across Africa.
Specimen below: "Sweet potato" (Ipomoea batatas 'Georgia Jet') collected in 2001 by Bonnie and Joe Isaac in a garden in Pennsylvania.
Specimen below: Your "classic" potato (Solanum tuberosum) collected in 1982 from a farm in Peru. Research suggests Peru to be the site of early domestication over 7,000 years ago.
Now it's a common forest invader in Pennsylvania, but it wasn't always. Collected on November 17, 1949, this specimen was found by Bayard Long in Delaware. Native to East Asia, Japanese stiltgrass (Microstegium vimineum) was introduced by accident to Knoxville, Tennessee around 1919, used as packing material for porcelain dishes from China. It has since become a major invasive species, spreading across forests of Eastern North America. It is commonly found along trails, forest roads, and floodplains. It has been shown to be facilitated by deer overabundance. A recent study of unconventional gas well pads (such as “fracking”) in Pennsylvania by Penn State researchers found that recent hydraulic fracturing activities facilitates stiltgrass invasion (Barlow et al., 2017 Journal of Environmental Management). You can read more on that research here.
Japanese stiltgrass was introduced more recently compared to many other troublesome invaders. It only became common in western PA in the past few decades. In fact, to my surprise, there weren't even any specimens in the museum's herbarium from Allegheny County (Pittsburgh area)! (But there are now).
Specimen pictured below was collected in the native range (Japan, hence its namesake) in 1981.
Images below: Japanese stiltgrass invading a forest understory in Fox Chapel, near Pittsburgh, PA.
This isn’t your typical herbarium specimen of Sassafras (Sassafras albidum). On November 4, 1933, this piece of Sassafras wood was collected by Otto Jennings at Linn Run/Rock Run, about 5 miles south of Ligonier, PA. It is unclear what motivated this collection, since Jennings did not normally collect wood like this. Given its bulky size, it is stored with the fruit collection in the herbarium, separate from the typical pressed specimens.
Sassafras is a medium-sized deciduous tree, native across Eastern North America. It is easily recognized by its uniquely mitten shaped leaves. The leaves are very aromatic when crushed in your hand, like many other species in the Laurel family (Lauraceae). They also turn a beautiful red in fall.
Sassafras has long been used by humans for medicine and food, both by Native Americans and later Europeans. Ever wonder where the “root” in root beer comes from? Root beer was traditionally made from sassafras roots or bark. But, since 1960, sassafras is no longer used in commercially made root beers. The FDA has shown safrole (the aromatic oil in sassafras roots and bark) to cause liver damage and/or cancer in high doses to laboratory animals. Many commercial root beers nowadays use artificial flavors.
Above: Specimen showing leaf shapes of Sassafras, collected by Hanne F. von Fuehrer,. She was instrumental in preparing many of the plants in Botany Hall at the Carnegie Museum of Natural History. Her work was often based on museum specimens.
Below: Sassafras in Fall.
Collected on a spooky Halloween night in 1931 (well, it might have been during the day, but let’s just say night), this specimen was found by Curator of Botany Otto Jennings at Dixmont Hollow (near Emsworth), PA. Witch hazel (Hamamelis virginiana) is a small deciduous tree found in forests and stream banks across the eastern US. This awesome native plant is a notable for its fall flowering, with long ribbon-shaped bright yellow petals. It flowers as the plant drops its leaves for fall, leaving branches with no leaves, but plentiful flowers. Witch hazel is among the last plants in our region to flower in the fall. As its fruit dry, it ejects the seeds, making a snapping sound.
Why the name “witch hazel?” Several explanations have been given. One is derivation from an old English word meaning “bendable.” More fitting for Halloween, another unverified claim is the plant was thought to be linked to witchcraft, both for its mysterious noises (snapping sounds during seed ejection) and supposed use in magic wands.
Image below: Another witch hazel specimen, collected November 16, 1884 in back of Allegheny Cemetery. (also pretty spooky)
There’s a deeper evolutionary history behind jack-o-lanterns and pumpkin spice lattes than you might think. Recent research from Penn State indicates the plant lineage might have went extinct had it not been for humans. Species in the genus Cucurbita (including pumpkins, gourds, squashes) were domesticated by humans in eastern North America about 10,000 years ago. That is, they were cultivated in gardens, likely first selected for the use of their durable rinds (anthropological evidence for gourds used as containers for drinking) and later as a food source. Most Cucurbita species went extinct around this time, coinciding with the extinction of large mammals that these species relied upon to spread their seeds. Their fruits were unpalatable to the smaller herbivores that did not go extinct. Ironically, it is human hunters, paired with climate change, that led to the extinction of large herbivores in North America. Modern day pumpkins have adapted to the Anthropocene.
Collected near Freedom (Beaver county, PA), this pumpkin specimen (Cucurbita pepo) was collected from Dun’s Farm in 1884 by John A. Shafer, who became the first Curator of Botany at the Carnegie Museum of Natural History a decade later.
Over 90 years old and still beautiful color! This red maple specimen was collected on October 23, 1926 by Otto Jennings during a field trip of the Botanical Society of Western PA to Chestnut Ridge in the beautiful Laurel Highlands of Pennsylvania. Red maple (Acer rubrum) is one of the most common trees in eastern North America. You can find it from southern Canada down to Florida and Minnesota down to eastern Texas. And it is renowned for its beautiful scarlet red foliage in autumn. Happy fall!
Red maple doing its beautiful fall thing. Ohiopyle State Park, September 30, 2017.
Kudzu is one of the more well-known weeds, at least by name, sometimes known as “the vine that ate the South.” Collected on October 13, 1997, this specimen was found by Sue Thompson and Bonnie Isaac near the I-376 Squirrel Hill tunnel, Pittsburgh. Kudzu (Pueraria lobata) was introduced to the US as an ornamental in 1876 at the Centennial International Exhibition in Philadelphia. The vine was initially prized in the South to provide shade. The vine was later promoted for use in erosion control. Although listed as a noxious weed in PA, it is more invasive in southern states. There, it has been estimated to spread at a rate of 2,500 acres per year (some say up to 150,000 acres per year, although this estimate has been questioned). Infestations of this plant undoubtedly causes ecological and economic damage.
Below is another specimen of kudzu, collected in its native range in Japan in 2002. Although plants are collected in both native and invasive ranges, few studies have compared specimens of the invasive species across continents.
Nancy Hanks Lincoln (mother of Abraham Lincoln) died on Oct. 5, 1818 from “milk sickness.” Milk sickness is caused by poisoning after drinking milk from cows that have eaten the plant white snakeroot (Ageratina altissima). Also known as “puking fever” or simply “the trembles,” early European-American settlers in the Midwest initially thought milk sickness was an infectious disease. It was soon realized that the unidentified illnesses were caused by drinking milk from cows that ate white snakeroot, which contains the chemical tremetol, a toxin which causes weakness, pain, vomiting, abdominal pain, and can lead to coma and death. The cattle of these early settlers often wandered into the forest to graze, seeking additional forage outside limited pastures. However, milk sickness is very uncommon today due to modern farming practices and cows rarely have access to eat this plant.
White snakeroot is a fall blooming, shade-tolerant species found in forests across the Eastern US, and commonly found throughout southwestern PA. This specimen pictured was collected in 1998 in southwestern Indiana, about 90 miles north of the Little Pigeon Creek Community, where Abraham Lincoln’s family lived.
white snakeroot at Trillium Trail, Fox Chapel Borough, PA (Allegheny Co.); Sept. 19, 2016