HEBERLING LAB

Plants are an important part of the urban landscape – both those planted species and those that are wild. There are more to “weeds” than you might think.  From sidewalk cracks downtown to city parks, plants are important to the ecological, economic, and human health of our city.  Understanding what plants thrive (or not) and their roles in a healthy, functional ecosystem in cities and human dominated environments that define the Anthropocene. With a recent award from the National Science Foundation (starting this September and running for 3 years ), we will be digitizing all specimens in the Carnegie Museum’s herbarium from the Mid-Atlantic Region (PA, MD, NY, NJ, DE & Washington, DC).  That is a total of nearly 190,000 specimens!  We are partnering with an ongoing herbarium digitization initiative, the Mid-Atlantic Megalopolis Project, which includes 11 other institutions in an effort to document and understand the past, present, and future plants in urban environments.
 
This specimen of Bellis perennis, also called “lawn daisy,” was collected just outside the museum in front of the Carnegie Library by former botany curator Otto Jennings on May 26, 1909.  This member of the sunflower family (Asteraceae) is native to Europe but has since been transported across the world and has become naturalized in many areas, joining the urban flora.
 
This project will facilitate a better understanding of the often-overlooked biodiversity in the city and the plants that make up Pittsburgh, both today and 150+ years ago.
 
Expect more posts in the coming months that highlight the Plants of Pittsburgh!  

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It is that time of year in Southwestern Pennsylvania.
​Kennywood and Idlewild are open!
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Although they’ve changed ownership over the past 100+ years of operation, both amusement parks have similar origins and remain favorite recreation spots for many across western PA and beyond. 
 
Located in Ligonier, PA in the heart of the beautiful Laurel Highlands, Idlewild goes back to May 1, 1878 when land owner William Darlington gave rights to Judge Thomas Mellon to use the grounds for picnic and pleasure. Judge Mellon owned the Ligonier Valley Railroad, and Idlewild was started as picnic park to attract people to the Ligonier Valley Railroad.  Darlington gave Mellon the permission “Without compensation in the shape of rent for three years from the first of April 1878 provided no timber or other trees are to be cut or injured – the underbrush you may clear out if you wish to do so.”  The park was an immediate hit, with the “tops of the [train] coaches were covered with boys.”  You can still see the Idlewild train station in the park today.  You can also visit the Ligonier Valley Railroad Museum to learn more about the history of the region and the Ligonier Valley Railroad at the recently restored Darlington Station in nearby Darlington.
 
Collected in late May, 1923, the specimen below was found by in by E.H. McClelland at Idlewild Park, near Ligonier, PA. This herbarium sheet actually contains two different phlox species, Phlox stolonifera (creeping phlox) and Phlox divaricata (wild blue phlox). There are at least seven species of phlox native to Pennsylvania.  Phlox is a popular choice among wildflower gardeners.  Phlox can be easily confused with Dame’s rocket (Hesperis matronalis), a non-native plant in the mustard family common along many wooded streams and roadsides.  An easy way to tell the difference is by the flowers: wild phlox have 5 petals while Dame’s rocket has 4 petals.  Dame’s rocket is in the mustard family, whose flower petals characteristically form an “+” or cross (hence its former family name Cruciferae; family now called Brassicaceae).  Take the Idlewild train through the woods and see if you can spot these species now, 95 years later.
 

​Located in West Mifflin, PA near Pittsburgh, PA, Kennywood has strikingly similar origins.  It opened as a “trolley park” in May 1899 as an attraction at the end of the Monongahela Street Railway (also owned by the Mellon family). It was long known as a popular picnic spot, even before the park’s opening.
 
The specimen below of Trillium erectum was collected in May 1903 in Kennywood (4 years after the park opened!). This beautiful spring flowering forest understory plant is commonly known as “Wake robin,” “red trillium,” or even “stinking Benjamin” (the flowers have a bit of a wet dog scent).  Trillium is done flowering in southwestern PA now but can still be seen, but with withered or no petals. 

Today is the famous botanist Carl Linnaeus' birthday, born on May 23, 1707.  Linnaeus was hugely influential in taxonomy and nomenclature, having named and described many species.

This specimen of Fritilaria meleagris was collected in Linnaeus' home country of Sweden, in 1894, 187 years to the day after he was born.  Not surprisingly, this species was named by Linnaeus, and included in his classic publication, Species Plantarum​ (1753).  Many formal scientific names are followed by "L." denoting Linnaeus as the authority attributed to naming the species.

Deer don’t just eat your garden, they eat native wildflowers too. That in of itself is not a problem.  After all, white tailed deer (Odocoileus virginianus) are native to Pennsylvania.  Deer in PA were once hunted to local extinction, having to be reintroduced.  But deer are now well beyond historic densities.  There are many reasons for this, including land use change (deer do well in forest margins resulting from forest fragmentation), absence of major predators (like the mountain lion, which is now extinct in PA), abundant food sources (like your garden and farms), and hunting management practices.  Deer management is a controversial topic, both for ethical reasons and for competing interests (e.g., managing deer herds for trophy hunting vs. maintaining historic levels for forest management).  The high densities of deer in PA has many consequences ranging from public health (disease carriers esp. tick-borne diseases), car accidents that result in human injury (and higher in car insurance rates), as well as the many ecological consequences (declines in native wildflowers, changes in forest tree composition and forest regeneration, and facilitation of non-native, invasive plants, to name a few).
 
But how do we really know the effects of deer overabundance?  Some impacts are quick, but many others result from chronic deer overabundance.  Long term deer exclosures provide one method to study the effects of deer on the landscape (monitoring fenced forest plots paired with unfenced plots).  These studies are important, but require maintenance and few date to more than a few decades.
 
A recent study introduced a method to measure the effects of deer overabundance using herbarium specimens in Quebec (Canada).  Marie-Pierre Beauvais and others paired historic herbarium specimens (dating back to 1848!) of the large flowered, white trillium (Trillium grandiflorum) with recent observations to find that plants in sites today (with deer) have significantly smaller leaves than those of herbarium specimens.

Read the abstract of the study here:  http://www.nrcresearchpress.com/doi/abs/10.1139/cjb-2016-0206#.WwLeZakh3OQ
 
This study shows the potential of herbaria as time capsules to understand the direct and indirect effects of human activities on our environment.  There is so much knowledge in these specimens waiting to provide insights into the Anthropocene.
 
The specimen of White trillium (Trillium grandiflorum) below (left) was collected on May 21, 1908 by Carnegie Museum of Natural History Botany curator Otto Jennings in Washington County, PA. 
 
Note the specimen on the left, collected in 2005.  I admit this particular comparison only shows two specimens at two time points (too small a sample size to be meaningful on its own) and is cherry picked, but I show these just to illustrate the immense potential to measure hypothesized changes in our plants as a result of human induced environmental changes.  I hope someday to follow up on the cool 2017 study by Beauvais and others using specimens to study changes in the flora western Pennsylvania as a result of historic and recent changes in our deer populations. 

Each specimen has a story. Some specimens are of particular scientific importance because of their biology and the data they provide (representing a unique, endemic, rare, or threatened species for example).  Other specimens are fascinating because of the story behind of the cultural story behind the specimen, whether it be the collector or the context in which it was collected.  And some specimens are of both of biological and cultural interest.  This recently stumbled upon specimen of olive (Olea europaea) is one of those specimens, in my opinion.
 
Olive trees are iconic plants that are native to the Mediterranean Basin but have been widely cultivated by humans for at least 7,000 years. Olive has many uses by humans, both for food (olive oil, olives, etc.) and for its use in rituals and symbolism (as an example, olive branch as a symbol for peace).  Olea europaea has a rich background in world religions, with references in ancient Greece, Rome, and mentioned in throughout the Bible and in Islamic holy texts, among others.
 
This specimen includes much more than the plant itself.  The label reads “BIBLE PALESTINE PLANTS” and even includes a bible reference, along with the other information that is conventionally on herbarium specimen labels: collected in Jerusalem, 3- 5 meters tall, noting “everywhere cultivated.”  Dated May (but no year).  The specimen includes a newspaper clipping (source unknown) about the species in the context of the Bible.  No collector is given, but it says “The American Colony, Jerusalem.”

​​What is the “American Colony?”  A quick google search shows that it is now a fancy hotel in Jerusalem.  But before that, it was the site of a Christian utopian society.  The colony was established in 1881 by Americans Anna and Horatio Spafford, who left Chicago after the Great Chicago Fire in 1871. A group of Swedish Christians also joined the group later.  The group did much community outreach and other activities until the 1950s. 
 
So where did this specimen come from?  Why was it collected?  When was it collected? By whom? All of these questions aren’t entirely clear.  Super intrigued, I dug up the accession records when this specimen was donated to the museum.

​The specimen was donated as a gift in 1921 by Lewis S. Hopkins of Kent, Ohio.  The accession records state “A set of ‘Bible Palestine Plants’ as put out by The American Colony, Jerusalem. 70 specimens.”  Lewis S. Hopkins (1872-1945), was a professor of botany at Kent State Normal School (now Kent State University).  He was also a member of the Botanical Society of Western Pennsylvania.  So, we still don’t know exactly when this specimen was collected (or by whom). Given the newspaper clipping and Bible verse with this specimen, I’m guessing it was used as an education tool. This specimen certainly has some history!
 
This species was also the focus of one of the coolest uses of herbarium species to date. In 1993, Beerling and Chaloner published a study where they measured the stomata (tiny pores on leaves for gas exchange) on Olea europaea leaves, using herbarium specimens dating from the PAST 3,000 YEARS!: 1991, 1978, 1818, pre-332 BC, and 1327BC.  The oldest specimen was not a herbarium specimen in the traditional sense, but leaf material from a funeral wreath from King Tutankhamun (“King Tut” of ancient Egypt fame), now archived at the Kew Gardens, London. Stomatal density (the number of pores per area) can provide key insights into past climates and plants responses to the environment. Plants respond to increased atmospheric carbon dioxide concentrations with fewer stomata. Knowing these responses in plant species alive today, this theory linking stomatal density and other leaf traits to the environment has been applied leaf fossils to reconstruct climates when the dinosaurs reigned. 
 
This jaw dropping study was published in the journal Annals of Botany in 1993.  

Many studies have since measured stomata using herbarium specimens and it remains an important use for herbarium specimens, providing critical insights into past, present, and future ecosystems.  BUT, using specimens dating back 3,000 years connected to Ancient Egypt, this study was no “ordinary” stomatal density study.
 
This classic study on stomatal densities using herbarium was the initial motivation for this Collected On This Day blog post...I just stumbled upon the unique American Colony story in the process!

Redbud is sure to catch your eye in the spring!  The picture above of redbud (Cercis canadensis)  in bloom was taken yesterday at Schenley Park.  Below illustrates how advanced leaf out was last spring (specimen on right), compared to 1915 (specimen on left: flowers, no leaves yet).