This giant clam is part of the Section of Mollusks’ hidden collection. You can get a special behind-the-scenes tour of the section most second Saturdays of the month at Carnegie Museum of Natural History!
Hidden Collection
Collected on this Day in 1993
Collected on June 23, 1993, this specimen was found by Fred Utech near the Loyalhanna Creek in Salem Township, Pennsylvania.
Do not let the common name affect your opinion of this plant! Butterfly weed (Aclepias tuberosa) is a beautiful plant, and the pollinators love the bright orange flowers. Native to eastern North America, it can be found in dry, full sun conditions. It is a great plant to add to your garden!
Like other milkweeds (butterfly weed is in the milkweed genus), butterfly weed flower clusters mature into seed pods, which eventual dry up to release airborne seeds in the late summer. The long, silk-like hairs (called pappi) have been used by Native Americans to make textiles.
Despite its looks, butterfly weed is poisonous to ingest. Like other milkweeds, this plant contains defensive chemicals called cardiac glycosides, which are poisonous to humans, livestock, and pets. Milkweeds vary in their toxicity depending on species and age of plant. Symptoms can include weakness, difficulty breathing, kidney damage, cardiac distress, pupil dilation, loss of muscle control, and respiratory paralysis.
Botanists at Carnegie Museum of Natural History share pieces of the herbarium’s historical hidden collection on the dates they were discovered or collected. Check back for more!
Mammals from the museum’s hidden collection
What do all of these scaly mammals from the museum’s hidden collection have in common? They don’t have teeth!
(Well… all except that tiger skull in the back. It has some big chompers!)
Collected on this Day in 1925
Collected on June 16, 1925, this specimen was found near Potter County, Pennsylvania by H.W. Graham.
Poison ivy (Toxicodendron radicans) is a species with which you might be very familiar! Poison ivy is a native woody vine found in wooded areas across the eastern United States. The species can take various forms and habits, growing as a vine along the ground, up a tree, or as a small shrub.
Poison ivy is famous for a chemical it produces, urushiol, which upon contact can cause a severe skin rash in humans. The rash, which can last up to several weeks, can also lead to an infection due to intense scratching that breaks the skin. Serious health effects can stem from ingesting urushiol or can cause other allergic reactions in eyes and throat when inhaling smoke from burned plants. If you come into contact with poison ivy, the best way to prevent an allergic reaction is washing with water and soap (or other detergent to wash off oils) as soon as possible. Some people are more sensitive to poison ivy than others or become more sensitive after repeated exposure.
Poison ivy is in the cashew plant family (Anacardiaceae), which includes several other species that produce skin irritants. In addition to poison ivy, poison oak, and poison sumac, the family also includes mangos and cashews. Interestingly, the shell of the cashew nut contains chemicals that can cause similar allergic skin reactions as poison ivy.
You might have heard “Leaves of three, let it be,” but what does that mean exactly? How do you know if it is poison ivy, poison oak, or poison sumac? Many plants might at first glance resemble poison ivy, but they can be easily distinguished. Poison ivy is common in woods, forest edges, roadsides, and weedy areas throughout Pennsylvania and has aerial, hairy-looking rootlets on stems of vines. Poison sumac (Toxicodendron vernix) is also native to Pennsylvania, but it is less common and only found in swamps and other persistently wet habitats. Poison sumac (Toxicodendron vernix) has leaves made up of many more leaflets than poison ivy. Lastly, poison oak (Toxicodendron diversilobum) is sometimes confused with poison ivy, but it is unlikely you encountered this species in Pennsylvania—it is only native to the western United States.
Botanists at Carnegie Museum of Natural History share pieces of the herbarium’s historical hidden collection on the dates they were discovered or collected. Check back for more!
Collected on this Day in 1923
Collected in late May, 1923, this specimen was found by E.H. McClelland at Idlewild Park, near Ligonier, Pennsylvania. 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 that is common along many wooded streams and roadsides. An easy way to tell the difference is by the flowers—wild phlox has five petals while Dame’s rocket has four petals. Dame’s rocket is in the mustard family, whose flower petals characteristically form a cross (hence its former family name Cruciferae).
Botanists at Carnegie
Museum of Natural History share pieces of the herbarium’s historical hidden
collection on the dates they were discovered or collected. Check back for more!
Collected today in 1952 & 2002
Both of these specimens were collected on May 17 in Pittsburgh’s Highland Park—but 50 years apart. John Bright collected the specimen on top in 1952. Fifty years later to the day, collection manager Bonnie Isaac unknowingly recollected the same species in the same location! If you look closely, you will notice the 1952 specimen did not yet produce seed by mid-May, while the 2002 specimen has already started developing the characteristic maple-like seeds. Due to increasing spring temperatures in recent decades, many plants tend to flower earlier, as shown through herbarium specimens.
Botanists at the museum are studying the impacts of human-caused environmental changes over the past century by following in the footsteps of past collectors. They are revisiting field sites on the same day to compare modern day plants to specimens collected over 100 years ago.
Sycamore maple (Acer pseudoplatanus) has been intentionally introduced across temperate regions, including the United States and New Zealand. It has since become invasive, meaning it actively spreads across the landscape and can cause ecological damage. It is less common than other invasive maples (such as Norway maple) in this region, but it is invasive in several sites in the Pittsburgh area.
Botanists at Carnegie Museum of Natural History share pieces of the herbarium’s historical hidden collection on the dates they were discovered or collected. Check back for more!