Mason Heberling

Perhaps not the most beautiful specimen in the collection, but check out the prickly stem! Former Carnegie Museum curator Otto Jennings described this species as “an obnoxious weed of farmlands and waste places” (1953).  This leafless specimen of Carolina nightshade (Solanum carolinense) was collected on November 9, 1915 in “Pittsburgh district” by Frank R. Alker. Carolina nightshade (also called horse nettle, wild tomato, and many other names) is in the potato/tomoato family (Solanaceae).  It is commonly found in disturbed and anthropogenic (human-made) environments, such as those in cities. 
 
Horse nettle is native to the Southeastern US, and now widely distributed as a naturalized species across the world. Although native to parts of the US (probably including PA), it is considered a noxious weed in some states.
 
This specimen is available virtually online at http://midatlanticherbaria.org/portal/collections/individual/index.php?occid=12257516&clid=0

Botanical signs of fall are everywhere, to name a few --  colorful leaves, apples, squash, pumpkins, and the many wild and cultivated fall flowers. Among the most popular plant flowers in fall are those in the genus Chrysanthemum (in the sunflower family, Asteraceae), or best known as simply “mums.” They are native to Asia, but many horticultural varieties exist. Mums have been cultivated by humans for at least several thousand years, with evidence in Chinese writings dating back to 15th century BC.
 
This beautiful mum specimen was collected in “Fall” in 1914 by John Jones at Phipps Conservatory, Schenley Park, Pittsburgh.
 
High resolution image available here: http://midatlanticherbaria.org/portal/collections/individual/index.php?occid=11826736&clid=0

​Staghorn sumac (Rhus typhina) collected on October 19, 1929 near Penn Hills (Rosedale), PA by W.R. Van Dersal. This species is in the cashew family (Anacardiaceae), which is includes many painfully irritating species like poison ivy and poison sumac (although both of these species are not closely related, but in different genera).
 
For some reason, staghorn sumac is one of those species that I find iconic in Western PA.  Common along roadsides, farms, and old fields.  Its leaves are often brilliant red in the fall.  The fruit persist on branches through winter.
 
Sumac specimens in the Carnegie Museum herbarium are now imaged and online!  Searchable at midatlanticherbaria.org.
 
High resolution image of this specimen can be found here: http://midatlanticherbaria.org/portal/collections/individual/index.php?occid=12232607&clid=0
 

Fall allergies causing you grief?  
 
Ragweed is a plant many people are (all too) familiar with.  Or at least their bodies are.  Common ragweed (Ambrosia artemisiifolia) is actually native to North America, but has been introduced across the world.  In many cases, this plant (or other ragweed species) are to blame for seasonal pollen allergies known as “hay fever.”  In summer and early fall, ragweed plants produce copious numbers of pollen grains, which are dispersed in the wind.  Don’t blame those insect-pollinated plants with showy flowers for your allergy troubles.  Wind pollinated plants like ragweed are your culprit. 
 
This ragweed specimen was collected by Bonnie and Joe Isaac in Lawrence county, Pennsylvania on October 8, 1995.  Bonnie is the collection manager in the Section of Botany at the museum, an active plant collector and field botanist, and an expert on the plants of Pennsylvania.
 
Although ragweed is native in the US, historical records (pollen deposited in sediment cores) suggest that this species was far less common in North America before European colonization.  This is perhaps not too surprising considering the species thrives in disturbed habitats that came with European colonization and urbanization.  A study published in 2014 by Martin and colleagues in the journal Molecular Ecology extracted DNA from nearly 500 historic herbarium specimens dating back to the 1800s to measure the genetic makeup prior widespread changes to the landscape in the late 19th century. Combined with data from recent collections, they found shifts in the genetic makeup of ragweed populations as the species was expanding in the United States. 
 
Read the study abstract here: https://onlinelibrary.wiley.com/doi/abs/10.1111/mec.12675

​Corn is a staple crop known well by many across the world.  Corn is used in a variety of ways including human food (from corn on the cob to corn syrup), animal feed, ethanol production, and especially this time of year, fall decoration and corn mazes. Corn is an economically important crop worldwide, with over 81 acres expected to have been harvested in the US alone this year.  But where did this plant come from?
 
Corn, better known to many as maize (Zea mays), is a domesticated plant.  Yes, plants can be domesticated, just as your pets.  Corn was domesticated from a wild grass species known as teosinte in Mexico approximately 8,700 years ago.  Like many other food crops, corn was domesticated by humans through artificial selection – that is, through selective breeding for traits of interest over many generations, causing the evolution of a species.  In the case of corn, teosinte evolved through human intervention by selecting seed from plants with desirable traits (such as large cobs), planting those seeds, again selecting the “best” plants, and repeating over decades.  Eventually, teosinte evolved from a many branching grass with small seed cobs to what we recognize as corn today – tall, unbranched plants with large, tasty cobs. 
 
This specimen is of a species of teosinte (Zea mays subspecies parviglumis) that is thought to be the close relative of the domesticated crop we know today (Zea mays subspecies mays).  This specimen was collected near the site of domestication in Mexico on October 2, 1982 by Hugh Iltis, a botanist and geneticist at the University of Wisconsin-Madison who studied teosinte species and an influential conservationist.   Note the species name on the label “Zea mays L. subsp. parviglumis var. parviglumis Iltis and Doebley” – his name at the end denotes Iltis was one of the scientists who named the taxonomic variety new to science in 1980. It was also collected in the “type locality,” meaning from the same spot where the specimen used to describe the species was collected. 

​Many invasive species in our region were ironically first introduced intentionally.  The tree-of-heaven (Ailanthus altissima) is one such example, originally praised with enthusiasm as a lovely garden tree, fast growing, well behaved, resistant to pests and pollution – therefore an excellent urban street tree.  Tree-of-heaven was introduced first to Europe from northern China, then to North America in the 1780s to a garden in Philadelphia.  Decades later (and several additional introductions), it grew in popularity to become widely available and adopted for use in town and city plantings through the mid-1800s, including New York City.  By the 1900s, it was widely naturalized in both urban and rural areas across much of the United States.  It is now recognized by most states as an invasive species.  Tree-of-heaven was the namesake tree in Betty Smith’s 1943 classic novel, A Tree Grows in Brooklyn.
 
This specimen was collected by Sue Thompson and Lawrence LaSpoda on September 28, 1983 in Panther Hollow, not far from the Carnegie Museum in Pittsburgh.
 
Keep an eye out for this weedy tree, which is common throughout the city and along highways.  Its seeds are especially noticeably this time of year and persist on the tree into the winter.

​Herbarium specimens are both an art and a science.  This fact is no more apparent than in the collaborations between Andrey Avinoff and Otto Jennings, which culminated in the 1953 book Wildflowers of Western Pennsylvania and the Upper Ohio Basin.  Jennings was a longtime curator of botany, professor at University of Pittsburgh, and served many roles at the Carnegie Museum (including director from 1945-1949). Avinoff was a lepidopterist (studied butterflies) and artist, who was Director of the Carnegie Museum from 1926-1945. The book features a detailed, scientific manual describing plant species found in the region written by Jennings, along 200 watercolor paintings of a subset of these species by Avinoff.  Jennings would travel across Western PA in search of the perfect specimen to return to the museum for Avinoff to paint while still fresh and unwithered.  Avinoff is said to have dropped everything he was doing upon Jennings’ return, and stay through the night to paint the flowers from still life.  Avinoff estimated that it took him about 1,600 hours to paint them all.
 
Some of these specimens were then pressed and remain in the Carnegie Museum’s herbarium today.  We know of 50 specimens that were used by Avinoff for his paintings.   
 
This specimen of squarrose goldenrod (Solidago squarrosa) is one of those specimens.  It was collected by Otto Jennings on September 21, 1941 on a ledge along the river bluffs near Bell’s Landing, Clearfield County, Pennsylvania. 
 
Both of scientific and cultural value, this specimen has a rich history, much more than “just” dried plants on paper.  While we know the history behind this particular one, each specimen has an important scientific and cultural story to tell. 

Dr. Avinoff, referring to his wildflower paintings -- 
​“These were my guiding principles:
(1) accuracy in form and color;
(2) portrayal of the individuality of the plant as to the character, position, arrangement, and venation of the leaves and the texture of their surfaces;
(3) decorative arrangement, composition, and spacing;
(4) strictly water color technique—only transparent pigment and no opaque colors, no white paint anywhere, not a single stroke used in the high lights. The white is the paper and all light parts are lighter washes of the pigment—thoroughbred aquarelle has been observed throughout.”

​This digital specimen is now online!: http://midatlanticherbaria.org/portal/collections/individual/index.php?occid=11795987&clid=0

We've embarked on a three-year project to digitize nearly 190,000 plant specimens collected in the region, making images and other data publicly available online. This effort is part of the Mid-Atlantic Megalopolis Project (mamdigitization.org), a network of thirteen herbaria spanning the densely populated urban corridor from Washington, D.C. to New York City to achieve a greater understanding of our urban areas, including the unique industrial and environmental history of the greater Pittsburgh region. This project is made possible by the National Science Foundation under grant no. 1801022. 

You can get to see plants from all over the world without ever leaving the herbarium.   Herbaria are powerful resources that enable research that would otherwise not be possible, comparing plant species collected from across the world, at different times of year.
 
This specimen of Japanese knotweed (Fallopia japonica, formerly known as Polygonum cuspidatum) was collected in China on Sept 14, 1989 by Q.X. Wang and J.L. Sun.
 
Even if you’ve never been to East Asia, this species might be familiar to you.  Although native to China, Japan, and Korea, Japanese knotweed is now common across much of the temperate world, including the United States and Europe.  In Pittsburgh, Japanese knotweed (and related introduced knotweed species) form dense stands along rivers, streams and roadsides.
 
Specimens collected from both the native and introduced ranges can be compared to better understand plant invasions.  For example, do invasive species look the same in their home range?
 
Although Collected On This Day posts tend to be biased towards specimens collected in Pennsylvania, the Carnegie Museum herbarium includes specimens from many countries across the world.  In fact, about 1/3 of the 530,000+ specimens are from outside the United States. 
 
How do these species from far away regions end up at the Carnegie Museum?  Many are from expeditions from botanists affiliated with the museum – much in the same way locally collected specimens become part of the collection.  But many others are obtained through exchange with other herbaria.  Many plant collectors often collect duplicate specimens to send to several herbaria.  Most herbaria have exchange programs, where specimens (usually duplicates) are exchanged between institutions.  This practice functions to build the collection to include new species and specimens.  But it also has an important function to safeguard the future of the data.  In the case of damage (such as pest outbreaks or even fire, in the recent devastating case at the Museu Nacional in Brazil), having specimens spread across several institutions helps ensure the future of specimens.
 
Note the label on this specimen shows this specimen was at one time associated with the herbarium of the Shanghai Museum of Natural History. 

​47 of the 96 specimens of Japanese knotweed in the Carnegie Museum’s herbarium were collected outside of the United States.

​It is now a common plant in forests across Pennsylvania, but it wasn’t always.  This specimen of Japanese stiltgrass (Microstegium vimineum) was collected on September 7, 2017 by Mason Heberling (me!) at Trillium Trail, Fox Chapel, PA.  Native to East Asia, Japanese stiltgrass is an annual grass that is said to have first been introduced accidentally 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).  Japanese stiltgrass is especially common in common disturbed moist forests, where available light in the understory is higher.  Therefore, it often carpets the forest floor in disturbed forests.  High densities of deer have also been shown to facilitate stiltgrass invasions.  In fact, much of this research was done at Trillium Trail by Susan Kalisz (then at University of Pittsburgh, now at University of Tennessee Knoxville).  Read more here: https://kaliszlab.weebly.com/uploads/2/5/1/2/25120034/knightsmithdaviskalisz-na_j2009.pdf   They used fences to exclude deer and found that stiltgrass was not present in fenced plots, but abundant when deer were allowed access. The Kalisz lab actively remains at Trillium Trail.
 
Although collected only two years ago, I was surprised to find that this specimen was the oldest Japanese stiltgrass specimen collected in Allegheny county!  There is a chance it had been collected earlier and exists in another herbarium. It was said to be uncommon (possibly absent) at Trillium Trail until 2002. 
 
What will our forests look like in another 10 years?  Herbarium specimens are important, verifiable sources to document our changing flora.  And ultimately, help conserve our flora.

Once you learn to recognize this grass, you are likely to see it everywhere in forests and forest edges in Western Pennsylvania. It is especially obvious in the Fall, when it flowers and has reached its peak growth. Note the faint white line along the center of the leaf blades.

​Microstegium vimineum carpeting the forest floor outside deer fences at Trillium Trail.  

Wildflower specimens collected at Compton's Mills in 1952.
Welcomed signs of late summer and fall pictured below (left to right): common boneset (Eupatorium perfoliatum), tall ironweed (Vernonia altissima), wreath goldenrod (Solidago caesia). 

​These specimens (and more) were collected on September 6, 1952 near Compton’s Mills (near Salisbury, PA, Somerset County) by Leroy Henry and Werner Buker. Henry was a long time Curator of Botany at the museum (1937-1973), and Buker was a math teacher at Perry High School, who was also a very active botanist at the museum.  Collectively, they collected nearly 50,000 specimens in the Carnegie Museum herbarium!
 
These specimens are part of a larger project ongoing in the Section of Botany at the Carnegie Museum.  Starting last year, we are revisiting historic sites across Western Pennsylvania, where former botanists have collected.  We are revisiting these sites in order to record and monitor biological change in the Anthropocene.  Are the same species present? (local extinction or persistence) Are new species present? (newly introduced invasive species)
 
We are also recollecting specimens from these historic sites to compare specimens collected decades to a century ago, to those collected today. For example, how are species affected by climate change? Are species flowering earlier? How are plant communities affected by invasive species and introduced pests? These are just a few of the many questions that can be answered.
 
With generous permission of the current landowner, we are able to recollect specimens at Compton’s Mills. Compton’s Mills is a site of a family-run historic grist/flour mill built in 1872 on the foundation of an even earlier mill. We have done some recollections at this site last spring, including specimens of the endemic Appalachian violet (Viola appalachiensis).  Compton’s Mills of also of special importance, as specimens collected from this site were used by Leroy Henry to formally describe the species new to science (known as “type” specimens.  Read about our recollection in Spring 2017 here: https://www.masonheberling.com/collected-on-this-day/collected-and-recollected-on-this-day).
 
This year we are revisiting in the late summer/early fall.
 
With data from Compton's Mills, in addition to repeatedly revisiting other sites across Western Pennsylvania, we will be able to document and understand a century of past, present, and future impacts of humans on the landscape-- a hallmark of the Anthropocene.

​Some of our first recollections were featured in the We Are Nature exhibition.  Although this exhibition recently ended, specimens from this project will remain on display in the Hall of Botany.