Monday, December 12, 2011

Mark Catesby

Last month I knew nothing of Mark Catesby. Now the man is becoming a friend, and getting to know him is introducing me to a whole cast of characters from the age of discovery. We come together through his dried plant specimens.

Mark Catesby (1682-1749) lived in Charleston, South Carolina from 1722 to 1726. During these years he traveled around the state collecting plant specimens and making observations on the natural history of the area. He sent his specimens to Hans Sloane in London. Sloane bound them into two volumes, H.S. 212 and H.S. 232, and made them part of his herbarium collection. After Catesby returned to England in 1726 he got to work on his Natural History of Carolina, Florida and the Bahama Islands, which include his own watercolors of flora and fauna he observed.

A couple of weeks ago Patrick McMillan and I sat down to identify and list the plants contained in the volumes – a quick and first step. Or so we thought. The volumes are a trove of treasures and minor mysteries. We’ve been solving some of them and uncovering new ones. What are these plants? Where were they collected? What relationship do the herbarium specimens have to the watercolors? Who made all the notes on the pages?

Identifying the specimens is easy if you have Patrick McMillan on your team. He can identify many of them at sight. What he can’t identify instantly, we look up – through images on the Internet, descriptions and keys in Alan S. Weakley’s Flora of the Southern and Mid-Atlantic States (Working draft 15 May 2011), occasional emails to experts in particular taxa. The plants’ beautiful state of preservation certainly helps – Catesby did a wonderful job pressing them, and whatever he or Sloane treated them with has kept away the vermin. I double check scientific names and authorities and transcribe all the text on the page attached to the specimen – there may be a little or a lot. Patrick adds notes if the specimen is particularly interesting.

Here’s how we work: We set up our MacBooks side by side. I keep track of our data in Bento, which is ideal for this purpose. Each specimen gets its own record. Every type of text on the page gets its own field within the record. I keep Weakley’s Flora open on my desktop for quick reference. We go through the volumes folio by folio, opening each page in Preview. The digital photographs are clear enough that we can zoom in close enough to see tiny (if jaggy) details – even pubescence is visible. I also keep open the University of Wisconsin’s digital facsimile of Catesby’s Natural History to cross-check specimens that appear as watercolors. The USDA Plants Database is handy for scientific names and images. We fire off the occasional email, and work together to decipher Catesby’s handwriting.

I said identification is easy. This work takes hours. We sit there for three hours, six hours, drinking black coffee as the day slips by and dried plants and Latin imprint themselves in our brains so that we dream in binomials. After that work is done, I go back through the images and finish the transcriptions and clean-up on my own. Patrick spends evenings at home working ahead on identifications. H.S. 212 has 96 folios and 259 specimens. H.S. 232 has 139 folios and we’ve identified about 170 specimens; there are a number of Bahamian plants in this collection, and we haven’t worried about them for the moment.

Organizing the texts on the pages presents some challenges. Catesby was older than Carl Linnaeus (1707-1778), so his work predates binomial nomenclature. Sloane wrote notes on many of the folios in his distinctive handwriting, mostly references to works by John Ray. Sloane (or someone) pasted Catesby’s own descriptions of a few specimens on the pages. Someone else with copperplate handwriting who lived after Linnaeus wrote Latin binomials – many of them correct but many others never seen before or since – that are pasted on the pages next to a number of specimens. Someone wrote little notations in pencil directly on the pages – cryptic notes such as “ii.34.” Richard A. Howard identified some of the specimens in 1982, and his typed labels are pasted onto the pages.

Some folios are covered with these different texts. Others contain no text at all, only dried plants. Those are the pages where an expert taxonomist really comes in handy. But the pages full of labels are the really fun ones. In my next posting I’ll explain more of what is going on with those labels, and how we are deciphering them all.

— Amy Hackney Blackwell