botanizing

Many Times Repeated

Leaf after leaf.  A series of opportunities.  I have been thinking about evolutionary opportunities.  Charles Darwin saw a source of evolutionary opportunity in bodies in which parts were “many times repeated.”  He wrote in the first edition of Origin of Species that:

“We have formerly seen that parts many times repeated are eminently liable to vary in number and structure; consequently it is quite probable that natural selection, during a long-continued course of modification, should have seized on a certain number of the primordially similar elements, many times repeated, and have adapted them to the most diverse purposes.”  (p. 418)

In the spiral stairs of leaves around the artichoke, we see an example of Darwin’s “parts many times repeated.”   These leaves of the artichoke, however, are all alike—little evolutionary opportunity has been taken on the artichoke’s leafy head.  In contrast, flowers demonstrate well the sense of Darwin’s idea.  Orchid flowers often have one petal, the lip, that is highly modified relative to the other petals.  We might even think about the transition in structure from petals to stamens, as in the photograph below of a nasturtium, as an example of modification among ‘parts many times repeated’ in flowers.

These evolutionary opportunities presented when parts are ‘many times repeated’ in the body of plants interest me.   How does evolution go from simple repetition of parts, as we see among the leaves of an artichoke, to the variation and specialization we find along the short length of a flower?

Hydrangea 2007

Hydrangea 2007, an international conference (http://www.hydrangea2007.be/en.php) devoted to hydrangeas for enthusiasts and gardeners, is approaching, and I’m speaking.   The conference, which will be held at the Ghent University Botanical Garden in Belgium, begins on 16 August.  And on Friday, I began work on my talk.  This involved perhaps an hour of pacing, and then I fixed tea, and then I made a trip to a vending machine for some chips.  With tea and chips, I settled into writing.

I typed my title—‘Becoming Hydrangea’—and went on to the senses that I want the audience to take from it. The first is an evolutionary sense—I want to convey the changes that occurred in Hydrangeaceae, the hydrangea family, to give rise to the plants that we recognize as hydrangeas. The hydrangea family includes several genera in addition to Hydrangea, and many of these would not be popularly recognized as cousins of Hydrangea.  The second sense of ‘becoming Hydrangea’ is taxonomic. Our studies to reconstruct the evolutionary history of the hydrangea family have shown that Hydrangea in an evolutionary sense is broader than what Hydrangea has been in recent taxonomies.  If we are to understand the diversity of hydrangeas, we need to change our taxonomy to reflect better our understanding of evolution in the Hydrangea lineage.

On Friday, I wrote those introductory ideas, explaining our knowledge of the evolutionary history of the family, how it is most closely related to Loasaceae, another family of research emphasis in my lab, and more deeply related to dogwoods, tupelo, and the dovetree.  I sketched notes on the timing of the evolutionary split between Loasaceae and the hydrangea family and described the geographic radiation that occurred within Hydrangeaceae.

After cleaning the bathroom, getting groceries, and starting a load of laundry, I went today to the writing table in the basement as the afternoon heat began to rise in my house.  There I wrote about the ecological and morphological changes that mark the lineage that would become Hydrangea and also began to write about the broadened sense that we need for the genus. 

Finally, the lineages of Hydrangea came up; I began to think about the important points that I would like to make about the diversity we find in Hydrangea.  And I began wonder where I’ve stored all of the images I’ve used over the last decade in talks about the evolution of hydrangeas.  This is a topic I haven’t addressed in detail for a few years, and I hesitate to think about the out-of-date storage devices on which all of my electronic files have been stored. 

Tomorrow morning, first thing, I must look for the cache of electronic images as well as the hoard of negatives and slides that I will need to make new images for the talk.

Composing

For the past several days I’ve been composing a research talk.  I’ll leave this weekend for a trip to Saskatoon for Plant Canada 2007, a meeting of various Canadian plant science organizations at which I’ve been invited to speak. 

On a cool day nearly two weeks ago, I started a fire in my fireplace and sat in my rocking chair with a yellow pad to sketch the arc of my talk.  Earlier in the spring I had submitted a title and abstract, which set the themes to address.  I outlined the set of data, how they would be ordered, and the basic conclusions, but other aspects of the talk’s arc occupied much of the thinking time in front of the fire.  History and ideas add significant depth to talks and can serve as the plot lines to propel the arc of the story.  It’s those elements that take quiet thought in the rocking chair as well as several cups of tea and trips into my library (even trips into my office).

From the sketch, I composed a rough script of the first third of the talk, a point where I was undecided about the best way to proceed.  That catch led me to begin making the visual presentation.  These talks are strongly visual and working on the Powerpoint slides can sometimes offer insights on how best to structure the information.

Another of the critical questions these talks raise is how to convey ideas with pictures. I’ve been asking myself idea by idea, bits of data by bits of data, slide by slide how to compose.  This is the consuming part of the process.  I worked steadily on slides for several days, thinking about their aesthetic appeal and focal points as well as the clarity of the ideas.  The slides need to hold audience attention, convey swiftly the ideas, and also give me a set of clues about what to say (because I won’t be using either script or notes).

I’ve scavenged slides from an old talk, but the ideas of the new talk are sufficiently different that most of the slides will be new for the Saskatoon talk.  Most slides will have one or more photographs; indeed, one slide has 13 photographs and a diagram.  My photographs of research materials have been captured largely on film, requiring me scan Kodachrome slides to acquire digital images to import into Powerpoint.  I’ve been scanning in the late afternoons after spending the day laying-out slides and writing text.  My mornings often have begun by cropping and adjusting the lighting of the digital images.  These images were then imported to fit around text and/or diagrams.  Many of these slides, which may be on the screen for no more than a minute, often take several hours to make.  This week there have been several ‘single slide days.’

I finished the slides of the Powerpoint presentation late on Thursday night and drafted the last few notes this morning.  I’ve printed the notes to use as I practice the talk to check how the information flows, to make sure the descriptions work, and to know precisely what points to make with each slide.  And I need to know that the talk will fit the time that I’ve been allotted. 

This evening I began to pack clothes, apples, oranges, and tea.  I’ve set my thermos on the counter to fill tomorrow morning with hot water.  My binoculars and bird book are with my camera.  First thing tomorrow morning, I’ll start driving north.

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The photograph is Mentzelia multiflora and is one of the images I'll use in my talk on evolutionary innovation in flowers.