jenniferpowell's picture

Polytrichum commune

Observed: 9th October 2011 By: jenniferpowell
DSCF3523
Description:
Identifications
Species interactions

No interactions present.

Comments

jja28's picture

Wrong group !

I think this should be under in the Plant group.

Jerry

jenniferpowell's picture

Nope moss isnt a plant.

Nope moss isnt a plant.

jennifer powell

jja28's picture

Humble pie !

Thanks, I was wrong. Humble pie duly eaten.

Jerry

AlanS's picture

No, you were right!

Unjustified pie consumption!

Alan

jenniferpowell's picture

easy mistake to make. :)

easy mistake to make. :)

jennifer powell

AlanS's picture

AAAAgh!!

Just noticed a horrible typo in my ID above, and we cannot edit revisions.

For "Very similar to Polytrichum formosum, but shorter and more a plant of woods and shady places.", read:

"Very similar to Polytrichum commune, but shorter and more a plant of woods and shady places."

jenniferpowell's picture

Does that mean i get to eat

Does that mean i get to eat pie now? Im going to go for rhubarb and pineapple!

When i was on a botany course a couple of years ago i got told that mosses wasnt part of the plant kingdom because the were single celled? Or am i confusing it with something else?

And thank you for the id.

jennifer powell

AlanS's picture

Don't get me started ...

This is something like an hour's lecture to our first year bioscience classes, but I'll try to keep to the point.

Mosses are multicellular and part of the kingdom Plantae. The hair-mosses, Polytrichum and its allies, are best regarded as the class Polytrichopsida within the phylum Bryophyta, within the Plant Kingdom. The true mosses are in the class Bryopsida, in the same phylum. Some authors (especially those of Amercican textbooks) have a much narrower concept of the rank of phylum and treat the different moss and liverwort groups as separate phyla, but this creates difficulties in classifying the phyla into higher units.

The confusion I think lies with the green algae, many of which are single-celled. These were accepted, quite rightly, as part of the plant kingdom, but there was much debate about classifying single-celled organisms in general and in 1969 a guy called Whittaker proposed a new classification - the "five kingdom" classification - in which he recognised kingdoms for plants, animals, fungi, and a single kingdom for all unicellular, 'eukaryotic' organisms, for which he adopted an existing name, the 'Protista'. (The fifth of the kingdoms was for bacteria etc., the Monera, which we now know to have encompassed the most fundamental division of all life on Earth, but that is a separate story.)

Now Whittaker was a brilliant and much liked scientist, and I met him at a conference in Germany when I was a young research student, and I regarded our half-hour conversation in a coffee shop in Hannover as one of the most inspiring moments of my research studentship. (And anyone who buys me a coffee earns my lifelong admiration.) However, I could never accept the Protista as a kingdom; it was too unnatural, combining completely unrelated organisms. Many others felt the same and alternative classifications were proposed, but the "five kingdom" classification became entrenched in American textbooks, usually presented as "fact" and with no mention of alternative views.

A noted dissident was a guy called Cavalier-Smith, in the 1980s and 1990s, and in 1998 he produced a major paper in which he showed the green algae to be rightfully part of the Plant Kingdom, as well as splitting the 'Protista' into two separate kingdoms of their own. Research scientists largely picked up on this but it has taken a while for textbook authors to catch up, and some still haven't.

DNA sequencing has resulted in substantially revised classifications of single-celled organisms, not yet reaching the textbooks, but the green algae remain firmly part of the Plant Kingdom, single-celled or not.

So yes, mosses are plants, and green algae are plants (as also are red algae and an obscure group, the Glaucophyta), but other algal groups are not.

Alan

jenniferpowell's picture

I should show this post to my

I should show this post to my current biodiversity lecturer who a couple of weeks ago taught us about the 5 kingdoms including the kingdom Protista and have been told the subject will be part of our exams, which is a bit worrying if what we are learning isnt the general agreed with flow.
Thank you for the indepth discription, is it ok if i print it out to show my lecturer?

jennifer powell

AlanS's picture

Hi Jennifer

You are welcome to show this to your lecturer, but I always tell my students that classifications are substantially a matter of opinion. I am not going to say that the "five kingdom" system is wrong, though personally I consider it misleading and unworkable - but that is just me. The important thing is that students see these classifications as hypotheses and not as cast-iron fact. Latest editions of major Biology textbooks, such as Campbell & Reece, are recognising this and are moving to more up to date classifications.

Even so, in a decade's time, people are going to be laughing at some of our present day beliefs.

Alan