Mason Heberling

Exactly 100 years ago, this specimen of pale jewelweed (Impatiens pallida) was collected by Otto Jennings - just across the street from the Carnegie Museum in a moist, narrow ravine in Pittsburgh's Schenley Park.  This specimen isn't just "any old" pale jewelweed.  Most pale jewelweed has bright lemon yellow flowers, but not always.  This specimen is a cream-colored form, formally described by Jennings in 1920 as Impatiens pallida forma speciosa. This particular specimen was referenced in his description of the cream-colored form, thereby making this specimen a holotype (that is, THE reference specimen for the taxon).  

To me, the difference in color is there, but subtle.  I'm not sure if the form is still "officially" recognized by most botanists or if much research has been done on flower color variation in the species.  But I am now keeping an eye out for it!

Photo by Greg Funka taken on August 27, 2019 in the type locality (Schenley Park)...100 years after Otto Jennings collected this specimen.

​Note the difference in color compared to photo below.

Collected on February 2, 1899, this specimen was found by Cyrus Pringle in lava fields near Cuernavaca, Mexico.  Pringle is a well-known American botanist and prolific plant collector, with over 500,000 specimens distributed in herbaria across the world!  To give this enormous number some context, his collections alone are nearly the size of the entire Carnegie Museum herbarium.  The herbarium at the University of Vermont is named after him.  The Carnegie Museum herbarium includes 5,378 specimens he collected.  During his life (1838-1911), Pringle discovered approximately 1,200 new species. 
 
In addition to the Northeastern US, many of Pringle’s specimens are from Mexico.  In 1885, Pringle was funded by Harvard to document the flora of Mexico.
 
This particular specimen is a type specimen of Agave hispida, meaning this particular specimen was used in the naming and description of this species as new to science.  There are many different categories of type specimens. More specifically, this specimen is considered an isoneotype: “iso-“ because it is a duplicate of the “neotype” (collected from the same plant).  The “neotype” is “neo-” (or new) because it was designated as the type after the original publication that first described the species.  The neotype of this species (pictured below) is in the United States National Herbarium (Smithsonian).

This isn’t your typical herbarium specimen (or is it?). It is a “type” specimen collected by A.H. Curtiss on December 15, 1903 on the Isle of Pines, Cuba.  A “type” specimen is a specimen that was used to formally describe the species as new to science.  Therefore, type specimens have very special scientific and cultural significance.  This species was named Acisanthera glandulifera in 1917 by Carnegie Museum curator of botany, Otto Jennings.  Jennings and others went on expeditions to Cuba in the early 1900s, and many specimens are now preserved at the Carnegie Museum. 
 
Type specimens serve as a verifiable record for future researchers to compare and verify a given species’ identity. There are many different categories of types.  In particular, this specimen is a “holotype,” meaning it is the sole designated specimen that describes the species. Current rules set forth by the botanical research community are that the species description much be published in a peer reviewed journal and must designate one single specimen as the holotype.  Because individuals can vary in their feature, other specimens can be referred to in the species description as well.  These specimens would be known as syntypes.  Similarly, a specimen which was said to be made from the same exact individual as the holotype is known as the isotype.  It is common practice for botanists to send duplicates of the holotype (aka "isotypes") to other museums to be a part of their collection. 
 
Taxonomy (the science of classifying organisms) is an ever-changing science, subject to revision as more research is done, especially at the molecular (DNA) level. What was once thought to be one species might actually be several, and what was thought to be several species might actually be one.  In addition to a species being recognized as new, some species simply change their names as a result of new evidence suggesting it should be being placed in a different genus (thereby changing its binomial scientific name).  It might seem unnecessary to go to the trouble to name species or have botanists argue over what is a species and what isn’t.  But taxonomy is very important for both our basic understanding of the tree of life, but also for biodiversity conservation.  If we don’t know what species are out there, we won’t be able to effectively conserve the world’s biodiversity.  After all, it is tough to protect a species you didn’t know it exists.
 
Another major reason for changes in species names is more due to nomenclature rules and dealing with synonyms.  A species may be independently described multiple times and many species have a complex nomenclatural history (that is, they have been called multiple scientific names by different people). Assigning one accepted scientific name to a species helps to ensure that scientists working on the same species are indeed referring to it as the same species.
 
You’ll notice many herbarium specimen labels have additional labels (annotation labels) to update the specimen’s identity as new information becomes known.  An annotation label can be seen in this specimen pictured here (specimen was first labelled as a different species name).  In fact, a recently published treatment of this genus (Guimaraes et al. 2017, Brittonia) suggests this species name should be Acisanthera erecta.
 
Although this specimen isn’t your average specimen, can you say it is a “typical” specimen? [insert laugh here]

Above/below: The original 1917 publication by Jennings describing this species.

Below: Many type specimens are now available online (CM’s specimens are currently available on https://plants.jstor.org/ ).   Pictured here are duplicate specimens of the holotype (isotypes) in other herbaria.  Below is one specimen from the New York Botanical Garden (NY) and another from the United States National Herbarium at the Smithsonian (US).   I was able to find these duplicate specimens in a matter of minutes --thanks to recent digitization efforts!

This specimen was collected near Compton's Mills (near Salisbury, PA in Somerset Co.) in 1952.  It is a type specimen, meaning it was specifically cited in the publication that formally described this species as new to science.  There was quite a bit of confusion regarding naming rules and ambiguities in the original publication, so this location is not technically the type locality. BUT it is certainly a botanically valuable specimen and site. It is a syntype... aka not THE specimen (holotype), but a specimen specifically mentioned in original publication. 

This week, we revisited Compton's Mills, on the same calendar day as this specimen was collected. Along with Bonnie Isaac and others at the museum, we are revisiting sites that we have historic collections and recollecting specimens.  We plan to compare old and new specimens to compare flowering phenology (e.g., is a species that was in full bloom on May 24 1952, now in fruit on the same calendar day 65 years later?), as well as other aspects of plant population and community changes at a particular site.  More soon on this project!