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Wednesday, July 31, 2013

Even in Death, Scientists Make New Discoveries


It had been four long years since I'd last seen the little nightshade that haunted my dreams. Spurred on by local botanists in Australia's Northern Territory, I had first seen the plant in Litchfield National Park in 2009. I could tell upon encountering it that this was a species yet to be described by science -- so I took some leaf samples for DNA analysis with the expectation that I would someday soon be naming a new species.
But by the time that I returned to relocate this mysterious plant in 2013, it still didn't have a formal scientific name. As it turned out, the only way around the delay would be through timely collaborations with other botanists -- including a former mentor who had been dead for almost two years.
This particular new species was relatively easy to find... but not so easy to catch in flower. To name a new species you need to be able to describe what it looks like. And species descriptions for plants nearly always include details related to their flowers. In 2009 I had spent days tromping through the bush with two colleagues and a student... and not a flower was found. Without blooms there would be no name.
Returning to Litchfield National Park in May of 2013, I again found that the plant was not in flower -- but there was promise. In a recently burned swathe of eucalyptus woodland near a rock formation called "The Lost City," dozens of stems had formed flower buds. It was only a matter of time.
For four days I camped nearby with my Bucknell colleague Beth Capaldi Evans and senior biology major Gemma Dugan so that we could check on the plants each day. For four days we delayed our return to Darwin and the airport from which we would soon head back home. And for four days the buds didn't open. In an impressive feat of botanical chastity, not a bloom would budge. We left The Lost City with our heads held low.
The collective actions of the region's botanists would save us, however -- for when we visited the NT Herbarium on the way back in from the field, I found that quite a few new specimens of this plant had been collected in the last few years. And several of these dried, pressed specimens had flowers on them!
My spirit renewed, I dove into the folders of specimens. I examined small parts with my hand lens; I measured organs with my little metric ruler; I took notes as if in a fever of taxonomic proportions. This species was finally going to be uncovered... and I was going to be the one to do it. I was lightheaded with geekish joy.
But someone had beaten me to the punch.
There, nestled into one of the folders, was a full page of hand-written notes attached to a specimen I hadn't seen before. I immediately recognized the handwriting as that of David Symon, the greatest nightshade expert in Australia's history. As a Ph.D. student working on a small group of these species in the early 2000s, I had often received penned letters from David in which he shared ideas and encouraged my work. In 2004, when David was 84 years of age, we spent about two weeks together collecting in the Outback, with me thrilled to be apprenticed to the master.
David had discovered and named many of the species I was studying, so I was keen to learn whatever I could around the campfire each night. On one memorable evening I shared with him that my most favorite of the names he designated was Solanum oedipus, which I assumed was a nod to the reproductive biology of the species (where small "son" flowers can pollinate the single large "mother" flower in a given cluster) -- only to have him remind me, somewhat scoldingly, that oedipus means "swollen foot" and was obviously a description of the base of the floral stems. I apparently needed to get my mind out of the gutter -- no easy task for a plant reproductive biologist.
Later, I would head west with other botanists, intent on collecting rare nightshades on the Kimberley Plateau, while David headed first back to Darwin and then on to his home city of Adelaide.
What I know now is that David also made a stop at the NT Herbarium before he went home. Once there, he came across an unusual specimen collected near the Fitzmaurice River in 1994. Recognizing that this was likely something novel, David commenced with describing it as a new form. He likely stopped short of publishing the new species for the same reason I have until now: under the heading "female flowers" he wrote, "Not seen."
He then filed his notes with the specimen, where I would find them a decade later -- two years after his death in 2011.
Science is a cumulative endeavor. Everything we do is built upon and inspired by the men and women who came before us, leaving behind sets of hypotheses for us to test and ideas for us to challenge and revise or accept and carry forward. Sometimes they leave behind complete bodies of work that can only be admired for their comprehensiveness, and sometimes they leave threads of things we can only hope to sew into something more whole.
Today I am doing some sewing. I'm stitching David's outstanding notes to my own observations, some of them derived from the flowering specimens collected by other Australian colleagues. I'm also adding new threads based on my DNA work and images generated with a scanning electron microscope, thus weaving a modern textile that wasn't even possible when David first started working in the field.
In a few months David and I will publish our new species together. We'll name it after one of the botanists who collected the flowering material that allowed us to proceed.
Until then, however, I will continue to relish our unexpected collaboration. I may even delay the publication a little bit longer.

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