More from The Signature of All Things

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This post may contain plot details and quotes from The Signature of All

In the midst of the drama and intrigue that plays out in this book are some great mossy points for discussion. 

At one point Alma mentions that mosses have no internal skeleton to support themselves growing tall, thus they are relatively short. Additionally they cannot transport water within their bodies. Bryophytes are typically called non-vascular because that lack the conducting tissues of xylem and phloem. These tissues transport water and sugars to and from the roots and leaves. 

This is a distinction that I would often point out between bryophytes and other plants. More recently I have come to question and debate this point. Some mosses do have cells that move water and sugars internally from one part or their body to another, called hydroids and leptoids. They are similar to the cells of xylem and phloem of vascular plants. Some of them are dead at maturity and/or have modified end walls with perforations, allowing for faster transport. What these cells lack is the compound lignin in their cell walls. Lignin both strengthens the cell walls and makes them impermeable to water. Creating stronger and less leaky transport tubes. Lignin is what gives wood its strength and enables trees to grow tall. Mosses have some of the chemical precursors to lignin (Ligrone et al. 2008), but they did not evolve this compound. So I get that lignin is important, but some bryophytes do have conducting cells that move water and sugars around in their bodies. I wouldn't call them vascular, but they are not lacking internal water transport either. 

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Alma describes mosses as being defined by what they lack. No flowers, no seed, no fruits, no roots, and no internal skeleton. Mosses also do not engage in sex. All these points are true except for the last one. Mosses do in fact produce offspring by sexual reproduction. They have eggs and swimming sperm that fuse to form the sporophyte offspring. My guess is that this inaccuracy was intentional. 

The alternation of generation in plants was elucidated in 1851 by Wilhelm Hofmeister (Kaplan and Cooke, 1996). Though Alma is described as having corresponded with researchers around the world, she may not have read Hofmeister's work. He was based in Germany and his 1851 work was printed by his family's publishing company. I am not sure how widely the work would have circulated at that time. Thus at this time the reproduction of mosses was a "mystery to the naked human eye". This aspect lead to their being known by the evocative name Cryptogamae, which means hidden marriage. 

So Alma's statement that mosses do not engage in sex was an accurate statement for that time in our scientific knowledge of plants. Kudos to the author and her bryological guru for their attention to detail. I think it is good when we acknowledge that science is not a static bank of knowledge. We are constantly discovering and expanding our understanding of the world around us. Looking back at the history of where science has been helps us to appreciate how far we have come

This is part of a series of posts about the bryology in The Signature of All. 
Click here for all the posts in the series. 

References

Kaplan, D. and T. Cooke. 1996. The genius of Wilhelm Hofmeister: The origin of causal-analytical research in plant development. American Journal of Botany 83: 1647-1660.

Ligrone, R., A. Carafa, J. G. Duckett, K. S. Renzaglia, K. Ruel. 2008. Immunocytochemical detection of lignin-related epitopes in cell walls in bryophytes and the charalean alga Nitella. Plant Systematics and Evolution 270: 257-272.

Hofmeister, W. 1851. Vergleichende Untersuchungen der Keimung, Entfaltung und Fruchtbildung hoherer Kryptogamen (Moose, Farne, Equisetaceen, Rhizokarpeen and Lykopodiaceen). und der Samenbildung der Coniferen. {Translated Title: Comparative studies of the germination, development  and fruiting of higher cryptogams (mosses, ferns, Equisetaceae, Rhizocarp and Lycopodiaceae). and seed formation of conifers.} F. Hofmeister, Leipzig.

Addressing the Gender Issue

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This post may contain plot details and quotes from The Signature of All Things. 

It may seem unsurprising that a female bryologist in the early 1800's would disguise her gender on her initial publications. At the time women were not welcomed into scientific circles. Thus Alma's first publications were authored A. Whittaker. Later in the book, with age and time she publishes under her full name, Alma Whittaker. 

"No initials were appended to the name - no evidence of degrees, no membership in distinguished gentlemanly scientific organizations. Nor was she even a "Mrs.," with the dignity that such a title affords a lady. By now, quite obviously, everyone knew she was a woman. It mattered little." 

The reason she says it mattered little is that the world of bryophytes is not a competitive domain and thus she had been allowed to enter with little resistance. This is not just a casual statement. It is supported by the data (Special Report on Women as Academic Authors, 1665-2010 - Chronicle of Higher Education). From 1665-1970 only 8.4% of Ecology and Evolution articles were published by women, whereas in the field of Bryology almost twice as many female authors published (16.3%). Unfortunately disparities in publication rates between the sexes still remain (see the report's data from 1991-2010). 

Why do these disparities still exist? Could it be that our innate biases against women in the sciences negatively impacts women's publication rates? It has been shown that both male and female scientists are significantly biased against female applicants for research positions (Moss-Racusin et al. 2012). This article is behind a paywall. If you do not have access and are interested in reading the full study drop me an email. I could see this spilling over into the realm of scientific publication. It is often easy to tell whether someone is male or female by their first name, opening the door to inherent biases, which could influence both editors and reviewers. 

Inspired by the research of Moss-Racusin and others, professors in the Ecology and Evolutionary Biology Department at the University of Connecticut are carrying out a gender-blind faculty search. Both applicants and reviewers are requested to use initials or refer to the person applying as 'the candidate'. In an earlier experiment, they attempted to redact all gender-identifying information from applications, but one committee member was able to guess the applicant's gender by the difference in space he vs. she takes up in a sentence (Jones and Urban 2013). They outline and give detailed examples to guide the removal of gender-identifying content. 

Even with these detailed guidelines, there is seemingly no way to address the potential issue that recommendation letter writers typically use different words when describing men vs. women (Madera et al. 2009) [HT to M.T-T. for bringing this point up at lunch]. An example might be using action words such as "independent" and "confident" to describe a man and communal words such as "nurturing" and "helpful" to describe a woman. Hopefully letter writers that are writing for a gender-neutral application will be more aware of gender-biases and thus some of these language differences will disappear. I wonder if they could use this gender-blind search to study that? They could address the question: Do recommendation letter writers use less gender-biased language when they are writing for a gender-neutral job search, compared to a job search where gender-neutrality was not explicitly mentioned in the job advertisement? I would be really interested to know if a gender-neutral job search could also influence recommendation letter language. 

Overall I think that this gender-blind faculty search is a progressive undertaking that will help raise awareness about gender-biases that still exist in the sciences and I am really interested to hear how the process goes. I feel positive that the steps they are taking will decrease bias. What I still wonder is whether this type of job search will result in an increase in the number of female faculty hired? Unfortunately this job search only gives us a sample size of one. Similar efforts are needed nation-wide before we will see if decreasing gender-bias results in more women faculty in the sciences. 

Just the Tip of the Iceberg - Part 3 The Signature of All Things

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This post may contain plot details and quotes from The Signature of All Things. 

The first five pages of Part 3 focus on mosses with an intensity that covers a wide breadth of topics. 

We are regaled with the fact that mosses are "effortless to transport". They are not only small and light, but easily dried and thus avoid spoilage. Due to these qualities, mosses have been used as packing material for goods and other plants for centuries. The Whittaker botanical company also took advantage of these mossy features, using them to ship plants. Thus Alma not only traded and imported mosses herself, but she was able to mine the crates stored in her family's warehouses, which were filled with dried mosses from around the globe. 

After years of study, Alma accumulated an extensive herbarium. She collected over 8,000 species of mosses, which seems to me a pretty high number considering Alma is written to have worked about 150 years ago. Currently the number of species of mosses is close to 12,500, so that puts Alma at having collected and identified 64% of present day moss species diversity. All without leaving her home in Pennsylvania. I wonder how many species of moss were described by 1848? I am not sure where I would even go to try to locate that fact? A species count from Hedwig would be too early, whereas Brotherus would be too late. Who would have been a contemporary bryologist of Alma Whittaker, living and working during the first half of the 1800's? I will have to do some digging around to see what bryological history I can uncover. 

Alma also writes several books that as a bryologist I would most certainly have on my shelf. By 48 years of age she has written The Complete Mosses of Pennsylvania and The Complete Mosses of the Northeastern United States and has just begun work on The Complete Mosses of North America. The titles of the books could have been a little more creative or perhaps variable, but the sense of her productivity is firmly established. 

In leu of these imaginary books, I would recommend these real identification guides for exploring mosses in Pennsylvania and the Northeast: Outstanding Mosses and Liverworts of Pennsylvania and Nearby States and Common Mosses of the Northeast and Appalachians. As for a good field guide that tackles mosses across all of North America, there are not any that I particularly like. Also a book covering mosses across the entire continent would be a pretty large tome to tote around in the field. My personal preference for identification is a regional guide with a more limited set of species to sift through. If you have a smartphone and internet access, a light field option with wide coverage could be the online Bryophyte Flora of North America. A key to the genera is posted here. Unfortunately all the links are broken and thus it is not connected to the descriptions. The full descriptions are arranged by family here, but you need to know the connections between the two to make them work together. The key is preliminary, so hopefully they will be linked in the final version.

The Mosses of her Passion - The Signature of All Things

From the LuEsther T. Mertz Library of
The New York Botanical Garden, Bronx, NY

***Spoiler Alert***

This post may contain plot details and quotes from The Signature of All Things. 
Proceed with caution!

The mosses have finally arrived as significant characters in Part 3! We discover that Alma has decided to devote her time and energies to studying mosses in the genus Dicranum and she becomes the world expert on this group.  I am most familiar with Dicranum scoparium, the broom moss, which is common in eastern deciduous forests. It's common name comes from the leaves that are all curving in the same direction, as though the moss had been used to sweep the floor. It is one of the first species I like to teach people when walking in the woods. It is charismatic and easy to recognize. 

The moss pictured in this plate is Dicranum squarrosum. The specific epithet of the scientific name describes the leaves of this species, which stick out at right angles to the stem. This arrangement is due to the leaves having a bend in them, which can be seen at the bottom center of the plate. 

It was a bit of a tease, or foreshadowing, that these images of Dicranum were placed at the end of Part I, long before Alma discovered her passion for mosses. Mostly it had me wondering when we would start to hear more about the mosses.  Stay tuned for more to come on the mosses of Part 3!

The Signature of All Things: Part 2 - Catching bryophyte fever

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This post may contain plot details and quotes from Parts 1 & 2 of The Signature of All Things. Proceed with caution!

The second part of The Signature of All Things focuses on the childhood of the main character Alma Whittaker. In my mind the true main characters, the bryophytes, have yet to truly arrive on the scene. There is a brief mention of mosses being used by birds as material for nest building. Alma also uses mosses to fill the chinks in the walls of her study to cut down on winter drafts. Hornworts come up during a scientific discussion between Alma and her colleague George Hawkes. He describes them to another friend as "...among our least sophisticated plants-". I take mild offense to that statement. I think hornworts are super interesting and highly sophisticated in their ability to establish a mutualistic interaction with cyanobacteria (blue-green algae). They have pores on the underside of the plant that open to allow the algae to enter. The algae then live and grow inside of the hornwort helping to fix nitrogen, making it available for the hornwort to use. I think that establishing a relationship like that is pretty sophisticated. Don't you?

At the tail end of Part 2 bryophytes take their rightful place at center stage. Alma has a revelation that right beneath her nose, on the land she has known her entire life, is a world unexplored. The miniature world of mosses. An entire rock may be covered by dozens of species that occupy distinct niches. A little sunnier over here, a little wetter over there, makes for diverse habitats even within a few feet. It is amazing how small changes in the microclimate can make such a big difference to the bryophytes. The description of Alma's epiphany to focus her botanical energies on mosses is full of lovely imagery, such as the passage below. 

"Now the miniature forest below her gaze sprang into majestic detail. She felt her breath catch. This was a stupefying kingdom. This was the Amazon jungle as seen from the back of a harpy eagle. She rode her eye above the surprising landscape, following its paths in every direction. Here were rich, abundant valleys filled with tiny trees of braided mermaid hair and minuscule, tangled vines. Here were barely visible tributaries running through that jungle..."

Having done so myself, falling in love with bryophytes is an amazing experience. Upon closer inspection, you realize that there is a world of wonder to explore in miniature. The closer you look the more there is to discover. An adventure that can last a lifetime. 

The Signature of All Things: Part 1

I read through the first part of The Signature of All Things this past weekend. There is not much to report on the bryological front. Mosses only popped in once or twice. They were used to pack seeds and other plants for transport during long ocean voyages of the 18th and 19th centuries. In this part of the book we are briefly introduced to the main character, Alma, at her birth. Mainly this section focuses on Alma's grandfather, father, and thus her botanical roots.

This book is at the top of my pleasure reading pile. More updates to come after I read through Part 2.