HEBERLING LAB

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.

A couple of creepers: plant doppelgängers
 
Did you know that many plant species have doppelgängers?  Check out these two species, both collected at the same site on August 22, 1965 by David Berkheimer in Everett Borough (Bedford county), Pennsylvania. 
 
With its distinctive hand-like leaves, Virginia creeper (Parthenocissus quinquefolia) is fairly well known, or at least looks familiar by many.  It is a woody vine in the grape plant family (Vitaceae), common to forests, forest edges, and urban areas in across eastern North America.  It is one of those ubiquitous but overlooked plants. The species is just about everywhere, climbing high up trees. But upon closer look, there are two similar looking species in Pennsylvania. Although less commonly recognized (though not all that uncommon to find!), thicket creeper (Parthenocissus inserta) looks very similar.  (note: there is some confusion, with some botanists calling this species as P. vitacea, but either way, there are definitely two species here).
 
So what’s the difference?  There are two easy ways to tell the difference.  First, the species have differences in their tendrils (the structures that wrap around branches, attaching the vine to the tree it is climbing).  Virginia creeper has clear adhesive, swollen disks where the tendrils attach to the tree.  In contrast, thicket creeper does not have these. (But to confuse you, they rarely do).  Second, the flowering/fruiting structures are different. Thicket creeper has branching inflorescences (stem structures with flowers/fruits), often in two main axes, with noticeably larger berries than Virginia creeper. Virginia creeper has an inflorescence that branches, often in zig-zag, random looking pattern, but most importantly – with a clear central axis.
 
Below: (left) no adhesive disks on tendrils for thicket creeper; (right) adhesive disks connecting  tendrils to host tree. Not to be confused with "hairy" poison ivy vines.

A couple years ago, I was confident I could pick Virginia creeper out of a line up.  But I must admit, I didn’t even know until last year there was another species that looked like Virginia creeper. It was a mind-blowing moment, and pretty much dropped everything to go exploring for the two species. I’m always curious every time I see these vines to figure out which species it is.  It turns out, thicket creeper is more common than I thought around Pittsburgh, especially along the rivers.
 
Keep an eye out for these species this fall, when they have developed fruits to easily tell them apart.  And on top of that, they have some of the most bright red, beautiful foliage of any plant in our area!
 
Check out these specimens (and more!) here:
http://midatlanticherbaria.org/portal/collections/list.php?db=328&catnum=CM064196%3B+CM064039&othercatnum=1
http://midatlanticherbaria.org/portal/collections/list.php?db=328&catnum=CM064491%3BCM064471&othercatnum=1

Thanks for your impatiens! A day late post.

Two specimens of jewelweed, Impatiens, collected on this day (well, yesterday) by Carnegie Museum curator Leroy Henry in 1944 in Ben Avon Heights, near Pittsburgh.  There are two species of jewelweed commonly found in Pennsylvania and in relatively wet, partly shady habitats across eastern North America. They can form dense stands along wet roadside ditches at edge of woods and in floodplain forests.  Henry collected both species in the same location, as they commonly grow together.
 
What’s the difference between these two specimens?  Though less obvious in specimen form, the most noticeable difference is flower color.  Common jewelweed (Impatiens capensis), also called spotted or orange jewelweed, has orang flowers. In contrast, the flowers of yellow jewelweed (Impatiens pallida), also called pale jewelweed, are...well, yellow.  Flower os both species have distinctive nectar spurs that jut out of the back of the flower. It is entertaining to watch bumblebees go from flower to flower in a stand of jewelweed.
 
Jewelweeds are herbaceous, annual plants with juicy stems that can range in size, from short to very tall.  A widespread story is that jewelweed can treat skin irritations, and in particular, helps prevent poison ivy rash by rubbing jewelweed on skin after contact with poison ivy.  I don’t know of this being supported with data.
 
Jewelweed is also often called “touch-me-not” because the developed seed pods eject seeds out when touched. It can be a fun activity for kids (and adults).
 
Jewelweed flowers open mid-summer and the plants continue to flower until killed by autumn frost.
 
Jewelweed produces two types of flowers – the obvious ones with nectar spurs that are visited by bees and also, tiny inconspicuous flowers that do not open.  These small flowers are self-pollinating (cleistogamous).
 
Deer often eat jewelweed. A recent study found that some populations of the species that have historically received a lot of deer browsing have evolved greater tolerance to herbivory. https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.12344
 
I’m always amazed how sensitive jewelweed leaves are to the sun. When exposed to direct sun, their leaves get very droopy.  But they seem to quickly bounce back.
 
Impatiens commonly planted in gardens are related (in the same genus) but are not the same species.
 
Check out these specimens (and more!) here:
http://midatlanticherbaria.org/portal/collections/list.php?db=328&catnum=CM064196%3B+CM064039&othercatnum=1

​30 years ago today!:
A milestone for Botany at the Carnegie Museum
 
On August 7, 1989, Bonnie Isaac started at the Carnegie Museum. She was initially hired at the museum to work on a project to database the plant collection, making it searchable and therefore more useable to understand the occurrence and distribution of plants across Pennsylvania (and beyond). Since then, a lot has happened. Thirty years later, Bonnie is now Collection Manager in the Section of Botany and Co-chair of Collections.
 
It is no exaggeration to say Bonnie’s influence on the Section of Botany has been monumental.  And continues to be.

As one of the top plant collectors over the Carnegie Museum’s 120+ year history, she has actively contributed to the growth of the herbarium, collecting several tens of thousands of specimens from across Pennsylvania and North America. These specimens now reside in herbaria across the world and have are actively used by research across the world to make exciting discoveries.
 
Bonnie played a pivotal role in the digitization of the Carnegie Museum herbarium, one of the first of its size to have all specimens in the entire collection with label data entered into a database and publicly available online. A huge accomplishment that took over a decade of her career to complete, the collection database has increased the research value and led to an massive increase in specimen use. The digitization of the herbarium continues today through a project facilitated by Bonnie and funded by the National Science Foundation to make high resolution digital images and georeferencing (assign latitude/longitude to plot on a map) to all specimens collected in the region.
 
Although she’s humble about it, Bonnie is an incredible field botanist and leading expert on the plants of Pennsylvania, especially those rare and threatened species of conservation concern. An expert in natural history collections management and methods, Bonnie has a specialized diploma on herbarium techniques from Royal Botanic Garden, Kew, England. She has a master’s degree from Youngstown State University, where she studied the ecology and distribution of a rare species.
 
Bonnie’s science and botanical knowledge impacts conservation decisions. Since 2001, she has served as a member of the Vascular Plant Technical Committee of the Pennsylvania Biological Survey, serving at various times over the past decades as president and recording secretary, which advised the state in determining the status of endangered and threatened plant species. She is currently working on a project funded by the Pennsylvania Department of Conservation and Natural Resources through the Wild Resources Conservation Program, revisiting many historic sites of 10 threatened species across the state to assess their current rarity status.
 
Beyond the walls of the museum, Bonnie has a huge impact on botanical research in Pennsylvania and fosters a public appreciation for the role of plants in our lives and ecosystem health.  She is a founding member of the “Pennsylvania Botany Symposium,” a group of committed volunteers who provide education and networking opportunities for professionals, amateurs, and students of botany, including a biennial symposium that gathers Pennsylvania botanists of all levels. Bonnie is also very active in the Botanical Society of Western Pennsylvania, one of the oldest botanical organizations in the country.  She  has served as President of the organization since 2005.
 
And if that is enough – she is friendly, too!
 
Happy work-iversary, Bonnie!