My Bryology Bookshelf - III

Mosses With A Hand Lens by A. J. Grout 

Third Edition - 1924

A Popular Guide to the Common or Conspicuous Mosses and Liverworts of the North-Eastern United States

In my search for a field guide to the mosses of New England, I came across this book at my university library. I then purchased my own copy to add to my reference shelf. You can check out the entire book here online at GoogleBooks.

Some great aspects of this book are that it is meant to be used with a hand lens. Other books require either a dissecting or compound microscope. The initial dichotomous key is a manageable length with 25 couplets. Then it spits into Acrocarpous and Pleurocarpous mosses that then have a 36 and 14 couplet key respectively. The line drawings are really well done and are quite informative for species identification. The photographs are ok, especially considering they are from 1924, but are pretty grainy and black & white. The diagrams for the liverworts are typically much smaller and with less detail. This may show a bias of the author toward the mosses.

Since the book is quite old some of the names of the genera are out of date. But it is interesting historically to see how the scientific names have changed from then to now.

Catharinea is now Atrichum

Webera is now Diphyscium

Georgia is now Tetraphis

Another interesting finding in this book is that hornworts are described as a specific type of liverwort. They are classified in the family Anthocerotaceae, The Horned Liverworts. Currently the hornworts are classified as a distinct lineage separate from the liverworts. Thus there are three main groups of Bryophytes; Mosses, Liverworts and Hornworts. I am not sure when hornworts were moved to their own lineage. Sometime between 1924 and now? This is a question for my lab-mate Juan Carlos. I will let you know what he says when I see him tomorrow.   
 

Timmia megapolitana

Here are some photos of the moss Timmia megapolitana, the species that I worked on for my Master's Thesis.  Its common name is the Indian Feather Moss, due to the calyptra that remains atop the sporophyte capsule, sticking up like a feather. (It really isn't a very politically correct common name. Maybe we could come up with something better. How about the Periscope Moss? Any other ideas?)

Anyway these are some photos that I took of the plants and my fieldsite out in Albany, New York. This was several years back and before I owned a digital camera. Thus the images are a little rough, since they are scans of prints. This species grows on calcium rich substrates. This area has a lot of limestone. The mosses grew on the sides of fissures in the rock (below right) or on the sides of small ledges (below left). I also found this species growing at an abandoned marble quarry in Vermont, another substrate that has a basic pH and is calcium rich. 

Lamellae Story Debunked

I have been relaying the science tale of lamellae as snorkels for quite a while now (here and here on this blog) and I recently came across some scientific literature that completely debunks that idea. Honestly I am not sure if I read about the snorkel idea somewhere or if it just emerged as common knowledge from taking classes and reading. Sometimes there are just "factoids" that exist our heads and we may not know where they came from. As a scientist I totally should have been more careful about the source of my information prior to relaying in the public sphere on this blog. Despite this embarrassing misleading information, I would like to offer a correction via this post.

The dilemma is that mosses and other bryophytes typically interact with water and air differently than other plants. Vascular plants have roots and internal plumbing (xylem cells) that move water into their body and they take gasses in via stomata, small openings in the leaf surface. Bryophytes on the other hand do not have roots or xylem cells to move the water, they absorb water directly through their entire plant body. They also do not have stomata on the gametophyte plant and thus take up gasses across their entire plant body, too.

Think of having to both drink and breath through your skin at the same time. The parts that are taking up water can't exchange gasses and the parts exchanging gasses can't take up water. So, what's a bryophyte to do?

Well Polytrichum has solved this dilemma using its lamellae. They are the green filaments of cells (see above) on the upper surface of the leaf. They are not acting as snorkels. Instead they are creating spaces for small pockets of air between the lamellae for gas exchange. The air spaces do not become filled by water due to a waxy cuticle that covers the epidermis and the cells at the tips of the lamellae. In Polytrichum water is acquired via internal conduction through the stem of the leafy gametophyte. This internal plumbing is not very advanced, but you can see some of the small conducting cells in the center of this cross-section through the stem of the leafy gametophyte. This plumbing continues into the leaves. 

So that is a bit about our current level of understanding when it comes to lamellae on Polytrichum leaves. Once again I apologize for any confusion I may have caused. It just goes to show that it is important to cite your sources and to double check the knowledge in your head every once in a while.

The papers that I consulted for writing up this explanation are listed below.

Proctor, MCF. (2005) Why do Polytrichaceae have lamellae? Journal of Bryology 27: 221-229.

Robert J. Thomas, Steve H. Ryder, Mark I. Gardner, Jonathan P. Sheetz and Stephen D. Nichipor. (1996) Photosynthetic Function of Leaf Lamellae in Polytrichum commune. Vol. 99, No. 1, pp. 6-11.

Sphagnum capsules

Sphagnum mosses (peat mosses) have a capsule with a really interesting manner of spore release. They open with an explosive *pop* that can be heard when this moss is close by. The mechanism by which this occurs has been described as internal air pressure building up as the capsules dry, shooting the lid off the top. This is the only type of moss that has an explosive opening, thus it has attracted some interest.

In lab group we recently read a paper that explored this mechanism to try to figure out the processes involved in their explosive opening.

Duckett, JG, S Pressel, KMY P'ng, KS Renzaglia. (2009) Exploding a myth: the capsule dehiscence mechanism and the function of pseudostomata in Sphagnum. 183:1053-1063.

I don't have any photos that illustrate the cool little capsules, but you can link here to the image gallery at the British Bryological Society to check them out (listed under Sphagnum fimbriatum).

In the above research study, they carried out a seemingly obvious, but previously unexamined experiment. They poked holes in the capsules, dried them out and then observed how many of the capsules opened explosively. With holes in the capsule air pressure should not be able to build up inside and you would predict that the lid would not pop off.

Despite poking holes in the capsules the lids still popped off. So the explosive nature is probably not due to a buildup of pressure. The researchers propose that the mechanism to explode off the lid is due to shrinkage of the capsule walls. The side walls of the capsule buckle in and the rigid lid (operculum) flies off.

I think that it is super cool when simple experiments can be used to test seemingly established biological ideas. It is even more fun when the results turn the established idea upside down. Boy, science is cool! 

Berry Go Round #26

The latest edition of the plant carnival Berry Go Round has been posted at Gravity's Rainbow. The theme for this edition is springtime. We have been experiencing a lot of those spring showers here in Connecticut lately. I am most definitely ready for some sunny spring weather for a change. But in the meantime check out the spring-spirit at the carnival. One of my posts from this past month was featured in the lineup. It is the post about the number of moss species worldwide.  

For more about blog carnivals and my posts about the earlier editions of Berry Go Round, click here.

Sporophytes of the Liverwort Aneura

 A few weeks back I took these photos of some liverworts in the genus Aneura. They are of the diploid sporophytes (two sets of chromosomes per cell). At maturity the ball shaped capsule is rapidly elevated on a thin, thread-like stalk. The capsule opens via four vertical sits to expose and disperse the spores within.

 When the capsule is immature and before the stalk has elongated the sporophytes look like these two images below. The capsules are the darkened areas at the tips.

 

An interesting aspect is that the stalk elongates quickly. Unlike mosses the stalk of the liverwort sporophyte does not become longer from cell divisions. It becomes longer by all the cells in the stalk expanding and elongating by increasing the liquid inside of their cells. That is why the cells of the stalk are clear. They are stretched very thin. Keep your eyes peeled for this type of sporophyte. This morphology is a key feature for identifying a liverwort.

Connecticut Botanical Society Workshop

An Introduction to Moss Identification

Saturday April 17, 2010 - 9:30am-12:30pm

Nature Center, 269 Oak Grove Street, Manchester, CT

I will be leading this workshop sponsored by the Connecticut Botanical Society next month. It is free and open to the public. Space is limited to 14 people, so if you are interested in attending please contact me.

Have you every walked through the woods to observe a carpet of mosses? Upon closer inspection you notice that there are a wide variety of patterns, shapes, and colors within such a small amount of space. In this session you will learn how to indentify and explore mosses. This introduction to mosses will be based upon properties that can be observed with a hand lens. Participants should wear sturdy shoes and dress for the weather. After the indoor introduction we will car pool to the field site (Bolton Notch State Park).  Coffee and light refreshments will be available at the start of the workshop.

Call or email Jessica Budke to register -  (860) 486-6306  jessica.budke@uconn.edu 

(Update 10 April 2010 - The Workshop is currently full. If you would like to be placed on the wait list feel free to contact me.)

My Bryology Bookshelf - II

Another book on my shelf is Gardening with Moss by F. F. Rockwell. I am not sure when I picked up this book, but there it was hiding on the shelf and I decided to give it another look...

And now I remember why I cannot recall when I picked up this book. The title is quite deceiving! You might think that it is another book about growing mosses in your garden similar to these two (here and here) that I have discussed before. But no, this book was written in the 1920's and the title should be 'How to use Peat Moss (Sphagnum) when Gardening Flowering Plants'. It is interesting as a historic text. The first chapter is all about peat moss and its utility in the garden. This chapter also features a nice story about the author's first meeting with peat moss. From what I can tell the rest of the book does have sound gardening advice, but it is probably the same information that you could get from a more recent book.

Overall I wouldn't recommend it if you are looking for a book on Moss Gardening, but as a history or gardening buff it might prove interesting. You can check out a limited preview of the book here at GoogleBooks.  

Takakia

You probably have not heard of this moss before. It it pretty rare and I actually don't know anyone who has seen them in the wild. There are only two species in the genus (Takakia ceratophylla and T. lepidozioides). The genus is native to western North America and a few locations in Asia. 

This moss has an interesting naming history. It was originally discovered with only green, photosynthetic gametophytes. As you can see from the photo at left the leaves are deeply lobed and filamentous. Initially, the gametophyte was identified and named in the liverwort genus, Lepidozia. It wasn't until almost 100 years later that Takakia was found with sporophytes. The sporophytes have a persistent and tough seta/stalk with a capsule that opens via a single curved slit. If it was really a liverwort the stalk would be thin, translucent and ephemeral with a capsule that opens by 4 longitudinal slits. Once the sporophytes were found these species were moved into the genus Takakia and they have been hereafter identified as mosses.

Pretty amazing that it took that long for scientists to discover the sporophytes and then to figure out that they are really mosses.

   

My Bryology Bookshelf - I

I recently started a list of recommended bryology books on my sidebar. However I wasn't sure how many of these books I had talked about in actual blog posts. So I decided to start up a group of posts that walk through the bryology books on my shelf.

A Trailside Guide to Mosses and Liverworts of the Cherokee National Forest by Paul Davison and How to Know the Mosses and Liverworts by Conrad and Redfearn are both discussed here. 

I have also posted about couple of books on growing mosses. Native Ferns, Moss, and Grasses: From Emerald Carpet to Amber Wave, Serene and Sensuous Plants for the Garden by William Cullina of the New England Wild Flower Society and Moss Gardening: Including Lichens, Liverworts and Other Miniatures by George Schenk.

I also wrote about the fabulous bryophyte dictionary, Mosses and Other Bryophytes, an Illustrated Glossary by Bill and Nancy Malcolm.

One of the books on my list that I have yet to talk about is my advisor's most recent book Introduction to Bryophytes by Alain Vanderpoorten and Bernard Goffinet.

When I helped teach and Undergraduate Course in Bryology a few years back we could have really used this text. We used some excerpts from the book Bryophyte Biology. I think that this is a great book too. Unfortunately it is pretty tough for the average undergraduate. Bryophyte Biology is geared more for a graduate student or professional audience.

I have yet to use the new book Introduction to Bryophytes to teach, but I think that it will work really well for that purpose. It is aimed at undergraduate biology students or science savvy amateurs. I have also used the book to hunt up some fun bryology facts for use during my moss walks. If you want to really dig into all the different types of bryophytes and their morphology then this is probably not the text for that endeavor. However it is a look at the biology of bryophytes from a number of different angles, such as Physiology, Conservation, Ecology, Biogeography and Evolution. 

Berry Go Round #25

The latest edition of the plant carnival Berry Go Round has been posted at Foothills Fancies. Since it is the February edition there is a fun chocolate-y theme throughout. Beware of reading if you have a sweet tooth or if it is before lunch. I almost decided to have a chocolate dessert before my lunch when I read the carnival this morning. 

One of my posts from this past month has been included in the lineup! It is the post where I discuss a new moss gardening book. BGR also mentioned that I recommended checking out the moss-cam. I have heard about the moss camera project that is run by researchers out in California, but I have not discussed it on my blog, nor do I have a link to it anywhere that I can see. I think that the credit for mentioning/blogging about the moss-cam should go to Dr. Lalita Calabria who has recently started a blog called "Adventures of a Phytochemist".  She has an extensive post about mosses and I think that might explain the confusion.

For more about blog carnivals and my posts about the earlier editions of Berry Go Round, click here.

How many mosses are there?

One of my bryology students told me that their friend could not believe that they were taking a course on mosses. Their friend's comment was that there is only one type of moss, right? The small green kind.

This question boggles my mind. Is there only one kind of bird? No. One kind of tree? No. One kind of moss? No. You have to get pretty specific in your definition of any living plant or animal before the answer to that type of question is yes. For example, is there only one kind of ostrich? Yes. Only one sugar maple tree? Yes. You get the idea.

So my point is there are many different types/species of mosses in the world. Just take a look at some patches of moss when you are out and about. I bet that when you get close to the mosses and really peer at them you will notice that the first patch does not look exactly the same as the the second patch.

The question that I more often get but have a hard time answering is, "How many species of mosses are there worldwide?". This presents a problem, because it depends on who you ask and whether they are a splitter or a lumper. (Basically - A splitter is a scientist who tends to find differences between organisms and then groups them in a way that creates more species. A lumper is a scientist who would look at the same organisms focus on the the similarities and then group them in a way that creates fewer or one species.) Those are not technical biology terms and these are my own informal definitions, but if you were to use either of them with a biologist who thinks about species they will most likely know what you mean.

In the end this makes for a difficult question  "How many species of mosses are there worldwide?" I have looked through a number of bryology and botany books on my shelves and here is the range of answers to this question. (The quotations are arranged in chronological order.)

Bryophyta by Parihar (1961) p.150 "... about 660 genera and 14,500 species."

The Structure and Life of Bryophytes by Watson (1971) p.16 "Some 14,000 species of moss are known and the great majority are sufficiently alike in structure to create a real difficulty for the taxonomist."

 

Biology of Plants by Raven, Evert and Eichhorn (1999) p.412  "...at least 9500 species of mosses, with new forms being discovered constantly, especially in the tropics."  

A Checklist of the Mosses by Crosby, Magill, Allen, and He (1999) p.1 "This Checklist recognizes 12,754 species. Although new species of mosses continue to be described, the number being recognized appears to be declining, because of increased synonomy."

Introduction to Bryology by Schofield (2001) p.10 "... contains approximately 10,000 species in nearly 700 genera."

Bryophyte Biology edited by Goffinet and Shaw (2009) Ch. 2 p.56 "With approximately 13,000 species, the Bryophyta compose the second most diverse phylum of land plants."

Introduction to Bryophytes by Vanderpoorten and Goffinet (2009) p.70 "Approximately 12,000 species are currently recognized,..."

From this survey we end up with an answer that ranges from 9500-14500 species of mosses. Scientists are usually comfortable with a high level of uncertainty so they may find that range a sufficient answer. Remember it's not as though there is a right answer and by giving a range scientists just don't know. The number of species is constantly changing as new ones are discovered and others may go extinct. It also depends on which expert you consult (splitter or lumper). So the answer to this question is in a constant state of fluctuation. 

I find that giving a single number is more satisfying if I do not want to go in the the whole explanation that I have given here. Usually I say that there are approximately 12,500 species of mosses and I quote A Checklist of the Mosses as my source. This count is going on ten years old at this point, but I think that it is the most accurate count that we currently have. It also looks like the two books from 2009 are following this count as well with their values that are a little above and below those of the checklist.

So, "How many species of mosses are there worldwide?" you may ask.

To that I would answer that there are approximately 12,500 (Crosby et al 1999).