Mason Heberling

Although often overlooked, herbarium specimens that were collected in cultivation have important uses. These plants were intentionally planted by humans rather than growing naturally in the wild.  These specimens were collected from farms, gardens, greenhouses, or even those planted in your yard or city parks.  These plant species are often economically important, providing benefits to humans in the form of food, medicine, fibers, or simply beauty.  The Carnegie Museum Herbarium has about 5,736 specimens that are known to be collected in cultivation, dating back to 1817!
 
This wheat (Triticum aestivum) specimen was collected on June 29, 1916 from a farm in Vallonia, Pennsylvania (Crawford County).  This specimen was collected well before the so-called “Green Revolution” of the 1930s-1960s when agriculture changed globally with new plant breeding technologies (high yielding crop varieties), increased pesticide use, and synthetic fertilizer production and use.  
 
Compare this particular wheat specimen (which barely fits on the herbarium sheet; note it is bent 3x to fit) to a much shorter one now on display in the We Are Nature: Living in the Anthropocene exhibit at the Carnegie Museum of Natural History. The specimen on display was collected nearly a 100 years later and is a dwarf variety.  This wheat cultivar was developed through plant breeding technologies in the mid-20th century to improve crop yields.  Semi-dwarf wheat was developed in Mexico in the 40s and 50s through plant breeding efforts led by Norman Borlaug, who later won the Nobel Peace Prize for his work that addressed world hunger through agricultural technologies.  The majority of the world's wheat crop is now a semi-dwarf variety.
 
Herbarium specimens collected in cultivation could provide important information on the types, traits, and genetics of crops grown over the past two centuries, a period of much change.  Are some disease-resistant genotypes or cultivars which no longer exist stored in herbaria? 
 
Another important, yet largely untapped, source of information in these specimens collected in cultivation is the non-native species planted intentionally for ornamental purposes.  Many of our non-native species which are now invasive and causing economic and ecological harm were first introduced intentionally for ornamental purposes. In many cases, information on some of the earliest introductions may be stored in herbaria.  These specimens are ripe for study.
 
Take oriental bittersweet (Celastrus orbiculatus) as an example.  Oriental bittersweet is a woody vine from East Asia, now a problematic invasive plant found throughout the Pittsburgh region and beyond.  It became particularly abundant in our region in the 1980s, now common to forests and roadside woods.  Interestingly, the oldest specimens collected in Allegheny County are not from the wild, but instead grown in cultivation in gardens.  Two specimens grown near Highland Park collected in 1916, followed by another specimen collected 34 years later (also in cultivation!).  It was not collected outside of a cultivated setting in the county until 1979.  And now, it is ubiquitous!  What insight can those first specimens collected in cultivation in 1916 tell us?  Were these the source of introduction? And more importantly, can they provide information on basic invasion processes to help us prevent future invasions by other species? 
 
Specimens collected in cultivation may be seen as “not natural” or otherwise less important than those collected in natural areas or found spontaneously growing without direct human intervention.  But it is clear that specimens collected from cultivation have an important role to play.  We must continue to record and archive cultivated species in natural history collections.  After all, human impact and the blurring of “nature” and “human-made” is the hallmark of the current era, the Anthropocene, so cultivated species document nature just the same way as “wild” occurring plants.

The French naturalist Michele Adanson is said to have called the baobab as “the most useful tree.” This particular specimen pictured above was collected on June 27, 2001 by E. Mboya and others in Tanzania.  The baobab is an incredible important tree to the people and wildlife of Africa.  The tree can live up to a thousand years old!  Baobab produces a hard fruit with white pulp that has long been a traditional food by native Africans, as well as a source for water, medicine, and shelter. For these reasons, it is also known as “the tree of life.”
 
The species (Adansonia digitata) was named by Linnaeus in honor of Michele Adanson, who studied specimens of this species in the 1700s.  The second part of the scientific name ("digitata") refers to the 5 finger-like leaflets that make up the compound leaf. Interestingly, the Carnegie Museum herbarium includes 20 specimens collected by Adanson himself, dating back to 1753.

The baobab (Adansonia digitata) is prominently featured in the Hall of African Wildlife at the Carnegie Museum.  The species biological and cultural presence in some  part of Africa is unmistakable.

Below:  Another baobab specimen collected in 1973 that shows the large, white flowers, which are primarily pollinated by bats. 

Herbarium specimens provide key insights into the Anthropocene.  In many cases, natural history collections are the only baseline we have to understand the widespread, complex effects of human activities on the earth systems over the past century.
 
This grass species shown here is of particular interest.  This specimen was collected in Cambridge, England on June 18, 1829.  This grass species (Alopecurus myosuroides), commonly known as “slender meadow foxtail” or “black-grass,” is a major weed in farm fields (especially wheat and barley), and can significantly reduce crop yields.
 
Unwanted plants (“weeds”) have been an ongoing fight for humans since the dawn of agriculture.  The  “Green Revolution” (1930s-1960s) was a point in human history when agricultural production increased at an enormous rate and at unprecedented scale, aided  by technological developments in crop breeding, pesticides, herbicides, and fertilizers.  It has been one time point suggested to mark the "official" start of the Anthropocene, a proposed geological era defined by human activities.
 
Herbicides are commonly used to control weeds to increase crop yields.  With the increase of herbicides, some plant species have evolved resistance to these herbicides. In a cool study in PLoS ONE in 2013, Délye et al. did a DNA analysis of herbarium specimens collected from 1788 to 1975 to show that some individuals of this grass species already possessed the gene mutations associated with herbicide resistance well before herbicides were widely used!  They show that the use of herbicides selected for these individuals, such that those individuals with herbicide resistance are now more abundant.
 
Who would have thought these specimens would be used this way?  There are so many known and yet to be known uses of herbaria.
 
The collector of this specimen back in 1829 certainly didn’t think it could be used to understand the evolution and effects of herbicide use over 175 years later!
 

​This should wake you up! This specimen of coffee (Coffea arabica) was collected on June 1847 in Jamaica by Jacob Wolle.  Coffea arabica, the source of Arabica beans, is the main species of coffee consumed by humans, and is cultivated worldwide.  The coffee “bean” is the seed – the hard pit inside the coffee fruit. 
 
Why does the Carnegie Museum have coffee specimens from Jamaica from the 1840s, you might ask?  Surprisingly, some of the oldest specimens in the Carnegie Museum herbarium were collected in Jamaica!  Jacob Wolle was the grandfather of William Holland, one of the first directors of the Carnegie Museum (from 1901-1922). Holland himself was born in Jamaica, where his father was a Moravian missionary. The CM herbarium has 2,514 specimens from Wolle’s collection, dating as far back as 1819!

The coffee specimen below, also from Jamaica, was collected by former Carnegie Museum director William Holland's father, Francis R. Holland in 1844.
 
This post was inspired by a group of artists from Vietnam whose art is inspired by coffee and coffee plantations.  They stopped by the herbarium earlier this year for inspiration.