At A.C. Moore Herbarium: Ecology

Diphasiastrum digitatum collected by Ronald Chicone, Jr. at Saluda Shoals Park, SC on Novemeber 5, 2000. A.C. Moore Herbarium, University of South Carolina, Columbia

The human brain has a problem with complexity; it can easily be overloaded, which is why simplification and classification are so important in human learning.  This helps to explain why a herbarium sheet usually displays a specimen, or maybe specimens, of a single species.  The plant is spread out so as many observable characteristics as possible are clearly displayed, and since only one species is involved, it makes the sheet easy to put into a single category, a particular species folder.  The same convention of solitude is found in botanical illustration even from the few early illustrations extant on papyrus (Griebeler, 2022).  However, to state the obvious, plants don’t grow this way.  A reminder of this is apparent on an unusual specimen from the A.C. Moore Herbarium (USCH) at the University of South Carolina, Columbia, the institution that is the subject of this series of posts.

The sheet in question is labeled and filed as Diphasiastrum digitatum (USCH0073424) formerly Lycopodium digitatum, a fern ally (see above).  What makes it so eye-catching is that distributed over the sheet are several leaves: one each of maple, oak, and elm.  These are listed on the label as among the species present in this hardwood forest habitat.  Such references are common on labels, but including specimens of the associated species is not.  The leaves are unlabeled, nor are leaves of all the trees mentioned on the label included.  Still, it’s a sheet that catches the eye, and also serves as a reminder that no plant is ever really alone on a sheet.

This Diphasiastrum was collected in 2000 by Ron Chicone, Jr.  A search of the USCH database turned many other specimens collected by him, though none as species-diverse as the Diphasiatrum.  A search of SERNEC, the database for the SouthEast Regional Network of Expertise and Collections, revealed many more of his specimens.  LinkedIn provided the information that Ronald Chicone, Jr. graduated from Coastal Carolina University and since then has held several positions, including one as herbarium staff at the University of South Florida.  He is now a land management specialist for the Brevard County Environmentally Endangered Lands Program in Florida.  So Chicone has spent his career looking at plants in ecological contexts, just as this specimen suggests. 

This fits well into Mason Heberling’s (2022) argument that plant collections have been underused by ecologists for many kinds of studies, including of seasonal and geographical variations in plant traits.  Now botanists are also looking at the roots of herbarium specimens to identify a species’ fungal partners and have successfully extracted DNA from many of them (Heberling & Burke, 2019).  Also, the soil on roots can harbor algae, yet another organism in a vascular plant’s ecosystem—and a reason to leave a little soil on a specimen’s roots (Parker, Schanen & Renner, 1976), though this is considered by some to be haphazard specimen preparation.

Also being investigated is insect damage to specimens’ leaves using a grid system to calculate the extent of eaten areas (Meineke et al., 2019), and it’s not uncommon to find dead insects on a specimen.  Years ago, D.R. Whitehead (1976) wrote an article entitled, “Collecting Beetles in Exotic Places: The Herbarium,” in which he argued that a plant collection was a good place to look for new beetle species.  There is also research on new species of tiny snails first found on plant specimens (Miquel & Bungartz, 2017).  At USCH, researchers have recently begun microscopic examination of invertebrates lurking on algae specimens.  So herbaria can be sources of many kinds of biodiversity beyond the plant world and can contribute to ecological studies on multispecies interactions, including those involving plant pathogens.  

Despite this, I don’t see Chicone’s approach as becoming common, though it does suggest the surprises that can be found in any herbarium.  He was just out of college when he made this collection, so he was relatively new to the world of botany and perhaps therefore less concerned with its traditions and constraints.  Yet, he was hardly a neophyte because the collection number for this specimen is 236.  He probably didn’t mount it, but he must have tucked those leaves into the newspaper in which he pressed the plant.  This means that someone at USCH thought enough of the inclusion to mount the leaves, rather than tossing them out as irrelevant.  So the mounter was also party to this innovation/anomaly.

I am hardly recommending that adding in associated species become standard herbarium practice, though it might be nice if specimens were crossed-reference with those collected at the same time and place.  What I do think is important about this sheet is its role as a reminder that there are many unspoken do’s and don’ts that botanists absorb while working in an herbarium, and it is good to be aware of these.  They are constraints that make botany more organized, and also perhaps more canalized. 

Note: I am very grateful to John Nelson and Herrick Brown for their very helpful commentaries and corrections on this series of posts.

References

Griebeler, A. (2022). Production and design of early illustrated herbals. Word & Image, 38(2), 104–122. https://doi.org/10.1080/02666286.2021.1951518

Heberling, J. M. (2022). Herbaria as big data sources of plant traits. International Journal of Plant Sciences, 183(2), 87–118. https://doi.org/10.1086/717623

Heberling, J. M., & Burke, D. J. (2019). Utilizing herbarium specimens to quantify historical mycorrhizal communities. Applications in Plant Sciences, 7(4), 1–11. https://doi.org/10.1002/aps3.1223

Meineke, E. K., Classen, A. T., Sanders, N. J., & Davies, T. J. (2019). Herbarium specimens reveal increasing herbivory over the past century. Journal of Ecology, 107(1), 105–117. https://doi.org/10.1111/1365-2745.13057

Miquel, S. E., & Bungartz, F. (2017). Snails found among herbarium specimens of Galapagos lichens and bryophytes, with the description of Scolodonta rinae (Gastropoda: Scolodontidae), a new species of carnivorous micro-mollusk. International Journal of Malacology, 173–186. https://doi.org/10.1127/arch.moll/146/173-186

Whitehead, D. R. (1976). Collecting beetles in exotic places: The herbarium. The Coleopterists Bulletin, 30(3), 249–250.