Our Science Was State-of-the-Art in the 1700s

This is the third post in a five-part series on Arctic flora research at the Canadian Museum of Nature. Join us as museum researcher Paul Sokoloff introduces the fieldwork and lab work involved in writing a new flora of the North American Arctic.

Each plant that we collect in the field (like that Oxytropis I got so excited about) goes into a clearly labelled plastic bag until we get back to camp. There, using a plant press—the state of the art back in the 1700s and changed very little today—we press and dry the plant for transport and long-term storage in a herbarium (a collection of dried plants). Further reading: an excellent description of the pressing and drying process.

An array of plants, uprooted and laid on a sheet of newspaper.

Capitate lousewort (Pedicularis capitata), arranged for pressing in the field. Image: Paul Sokoloff © Canadian Museum of Nature

In 2010, we brought back just shy of 1000 such plant specimens from our trip to Victoria Island, in the Northwest Territories. The year before that, we brought in 1000 as well. With the museum’s collecting legacy stretching back to the 1800s, and specimens donated by many generous collectors outside the museum, the numbers start to really add up.

Herbarium cabinets, one of which is open to reveal stacks of herbarium sheets.

The fruit of a single field season. Image: Paul Sokoloff © Canadian Museum of Nature

Our last estimate puts the holdings of the Canadian Museum of Nature’s National Herbarium of Canada at more than 700 000 vascular plant samples, and that’s not even including the large collections of mosses and lichens.

So why keep all these dead plants glued to sheets anyways? In the inaugural post of this series, I mentioned that each herbarium sample becomes a record for our new flora. It goes much deeper than that: the National Herbarium of Canada, and all herbaria with Arctic collections, underpin the entire project.

We could not write this flora without them. These specimens provide the occurrence data by which we can plot the range of a species onto a map. Data on the habitat type and associated species, often found on the herbarium specimen, inform us about the ecology of the species.

However, the most important function of the collection is to establish and clarify the taxonomy of plants: the naming of natural evolutionary groups that we often call species. Through the examination of the morphology of an individual—the length and shape of the leaf or the microscopic structure of the flower, for instance—we can classify the plant.

A person looks through a microscope.

University of Ottawa student Katya Boudko examines a species of Elymus (wildrye) using a microscope. Though the technology has improved, this is the same technique that botanists have used to classify plants for 300 years. Image: Paul Sokoloff © Canadian Museum of Nature

A botanist examining a given specimen can assign a plant to a family, a genus and a species, each grouping (or taxon) being more morphologically similar than the last. Based on these increasingly fine morphological distinctions, a key for identifying a species based on shared physical characteristics can be written.

A herbarium sheet.

Pedicularis capitata mounted on a herbarium sheet ready to be filed in the herbarium. The label in the corner of the sheet contains data that includes the location where the plant was collected, the name of the collector, and the date when the collection was made. Image: Paul Sokoloff © Canadian Museum of Nature

Ultimately, the herbarium is the reference by which a botanist can compare specimens and group them in this systematic manner. This is how we organize all known plant species, and in turn, our Arctic flora of Canada and Alaska.

Maintaining the collection permanently allows botanists to confirm the identity of specimens, correct a mistaken identification, re-evaluate the taxonomic boundaries of a species based on new data, or bring a new perspective to the group.

The truth is that botanists do sometimes disagree on what defines a species (fortunately, these are always civil interactions). However, the more a group of plants is looked at, examined and debated, the closer we can get to an understanding of the true evolutionary relationships within that group.

This is particularly the case when it comes to the recent advent of DNA sequencing and molecular systematics—which in some cases have upended the classification of entire groups. This however, is a story for my next instalment.

A room with metal cabinets, bins, a filing trolley, a table.

The National Herbarium of Canada. More than half a million vascular plant specimens are arranged here in systematic order, available for researchers to examine on site or through loans shipped all over the world. Image: Paul Sokoloff © Canadian Museum of Nature

This entry was posted in Collections, Plants and Algae, Research and tagged , . Bookmark the permalink.

One Response to Our Science Was State-of-the-Art in the 1700s

  1. Pingback: The Last W: Why Our Flora Is Important (and Urgently Needed) | Canadian Museum of Nature – Blog

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