Quillworts and glassworts

Guest post by Lytton John Musselman

Teaching courses about wetland plants at a university on the shores of Chesapeake Bay for almost four decades privileged me to observe and study the wonderful panoply of vegetation in the waters of the Bay, its shores, marshes, beaches, and swamps. Unabashedly, I love these organisms and never tire of seeing them in their habitat, learning about their struggles and successes, their seasonality, the nuances of their habitat requirements, their human uses from food to glass making.  It is a great blessing to be a botanist with a career centered on plants and to share their wonder. I love introducing students to these denizens of the Bay.

One of these students was David Knepper who became interested in plants as an undergraduate and pursued a career in botany where he now shares his knowledge with a wide array of people.  David was a logical partner in this work and someone who shares my fascination with plants. And like any teacher, I am proud that I now learn so much from him, one of the advantages of having a long career in one place.

Quillworts, species of the genus Isoetes

Both David and I have our favorite Bay plants.  Mine is the group of fern allies known as quillworts.  Fern allies don’t necessarily look like ferns but have a life cycle similar to ferns and are evolutionarily related.  I would not hesitate to say that quillworts, species of the genus Isoetes are perhaps the least studied group of plants in the United States.  They are thunderously underwhelming, appearing like a grass—very narrow leaves that taper to a point with a swollen base giving the appearance of an old-fashioned writing quill, hence the name quillwort.  David and I published a paper on these fascinating plants, comprising perhaps six species in the Bay, several years ago and since that time we have found several species new to science.

That is remarkable, considering the long tradition of botany in the Bay region where scientists from the Smithsonian and the many universities around the Bay have studied for years.  Even more remarkable is that Isoetes mattaponica is a narrow endemic found only in Bay waters.  In fact, it is the only plant endemic to the Bay.  In a previous geologic era it may have been more widespread; recent molecular research has discovered the I. mattaponica genome in other quillworts as far afield as Tennessee.

This unassuming (like all quillworts) plant is rare and becoming rarer.  It inhabits pristine freshwater tidal marshes and grows interstitially among emergent marsh plants, making I. mattaponica difficult to find.  In the past few years we have watched with alarm as several of these populations restricted to the Mattaponi, Pamunkey, and Chickahominy Rivers have become increasingly smothered by two nasty invasives—hydrilla (Hydrilla verticillata) and aneilema (Aneilema keisak).

How ironic it would be that a plant found not long ago would become extinct within the lifetime of the discoverers. How many more endemic quillworts might there be? How many have we already lost?

Glassworts, species of the genus Salicornia

Quillworts have virtually no direct economic value but they are invaluable indices of habitat quality.  Conversely, the glassworts (species of the genus Salicornia and the various genera that have been separated from this

genus with resultant taxonomic dissonance) have been used since ancient times for making glass.  The connection between a salt marsh plant and the production of glass may seem remote until you realize that these halophytes (salt-loving plants) provide a source of soda ash, a mixture of chemicals necessary in glass production.  The plants are harvested and burned, the ashes then mixed with the raw materials of glass.

It is counterintuitive to think that plants used to make glass also make a good meal but that is the case with glassworts.  All our species are edible but seldom collected while in Europe they are considered a delicacy.  One of my former students worked as a chef in Paris and refers to them as haricots verts de la mer “green beans from the sea,” as they are known in French—a real delicacy and easy to prepare.  They are plated for serving like green beans, or more commonly, scattered over a fish or sauced seafood dish. The second use adds flavor and good green color to the plate.  Simply steam the young stems; no salt is needed since these plants accumulate salt.

Lytton John Musselman is Mary Payne Hogan Professor of Botany and manager of the Blackwater Ecologic Preserve at Old Dominion University. His latest book, coauthored with David Knepper, is Plants of the Chesapeake Bay: A Guide to Wildflowers, Grasses, Aquatic Vegetation, Trees, Shrubs, and Other Flora.

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