Field of Science

Berry Go Round #28

The latest edition of the plant carnival Berry Go Round has been posted at Greg Laden's blog. This month there is a lot of interesting items to read about non-mossy-plants. Enjoy!   


Hornworts, A Separate Group?

A few weeks back (My Bryology Bookshelf III) I had a question about when hornworts were moved from being recognized as a type of liverwort to their own independent lineage. I put this question to my lab-mate Juan Carlos and he came up with this response.

Since the flat thalloid gametophyte looks quite similar between hornworts and some liverworts, they were thought to be to be a type of liverwort. They were definitely thought to be unique due to their sporophyte. Hornwort sporophytes grow from the base and open by two longitudinal slits that start from the top and move toward the bottom. The spores line the entire length of the interior of the sporophyte. Whereas liverwort sporophytes consist of a spore filled capsule atop a thin translucent stalk.

One of the first researchers to publicly recognize the hornworts as their own phylum (Anthocerotophyta) was Rothmaler in 1951. So there's the answer to my question. When were hornworts recognized as a separate lineage?

For more information on hornwort classification check out this scientific article.
Raymond E. Stotler and Barbara Crandall-Stotler. 2005. A Revised Classification of the Anthocerotophyta and a Checklist of the Hornworts of North America, North of Mexico. The Bryologist 108:16-26.

My Bryology Bookshelf IV

I led a moss walk several weeks back. On that outing I heard about a book that includes some bryophyte identification that I had not seen before. It is A Golden Guide: Non-Flowering Plants by F. S. Shuttleworth and H. S. Zim. It is an older book, with the latest edition having been published in 1967, and is out of print. I found a used edition online. It covers a broad array of organisms, including Algae, Fungi, Lichens, Mosses, Liverworts, Hornworts, Ferns, and Gymnosperms.

The book describes 34 different mosses, 12 liverworts and one hornwort. There is a short introduction to mosses that includes information on their life cycle and basic morphology. The guide includes small color illustrations. They don't give too much detail but do give you a general sense of the morphology of the plants. Each moss has a short sentence about the habitat, some information about the species morphology and then some numbers to indicate the general size of the plants.

My main critique is that a majority of the bryophytes in the book do not have their scientific names listed. They only have a common name. Contrary to other scientists I know, I like to use common names when teaching mosses to the public. However I always use them in conjunction with the scientific name. Common names can vary depending on the area of the country you are in or which language you speak. Scientific names are all in latin and thus have stability no matter where you are or what language you speak. They are critical to be sure that everyone is communicating about the same type of plant. From the descriptions, some of the genera are easy enough to identify but others may take a little more effort to identify. 

If you are looking for a bryophyte guide, I don't think that it is the first book that I would buy. However if you already have quite a few books it might be another interesting one to add to your collection.