Talk:Moss

From Wikipedia, the free encyclopedia

	Moss is within the scope of WikiProject Plants, an attempt to better organize information in articles related to plants and botany. For more information, visit the project page.
B	This article has been rated as B-class on the quality scale.
High	This article has been rated as High-importance on the importance scale.

	Antarctica Portal This article is within the scope of the WikiProject Antarctica, which collaborates on articles related to Antarctica. To participate, you can edit this article or visit the project page for more details.
B	This article has been rated as B-Class on the quality scale.
Mid	This article has been rated as Mid-importance on the importance scale.
Additional information: Related work groups:

This article has been reviewed by the Version 1.0 Editorial Team.

Additional information: B This article has been rated as B-Class on the assessment scale. Feel free to make short comments here to identify the strengths and weaknesses of the article. ??? This article has not yet received an importance rating on the assessment scale. This article is included in the 2006 Wikipedia CD Selection, or is a candidate for inclusion in the next version. Please maintain high quality standards and, if possible, stick to GFDL-compatible images.

Moss was a good article nominee, but did not meet the good article criteria at the time. There are suggestions below for improving the article. Once these are addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake. Reviewed version: April 3, 2007

Contents 1 Number of species 2 On the north side? 3 Start it simpler 4 Dioicous vs Dioecious 5 Image name is misleading 6 moss uses 7 GA review 8 Ant on moss image 9 Moss leaves and stems

[edit] Number of species

This page should say how many species of moss there are. --Savant13 14:01, 21 December 2006 (UTC)

[edit] On the north side?

Is it true that moss only grows on the north side of something, or is this a myth? It sounds false, because I can't think of a single aspect of nature that makes north special.

Bear in mind that I know nothing about mosses, but certainly in the northern hemisphere the north side of anything will get less light, and it does say in the article that mosses prefer low light situations. Maccoinnich 17:16, Mar 12, 2005 (UTC)

Indeed, in northern latitudes the north side of trees generally will have more moss on average than other sides. South of the equator the reverse is true. No Account

But why is this so? Have there been any studies on this? PeepP 13:48, 20 October 2005 (UTC)

The evidence points to this being a reproductive issue. The gametophyte generation in mosses, liverworts and ferns all require the presence of liquid water to allow the motile male gametes to reach the female gametes. In the absence of water no reproduction takes place. Hence the characteristic feature of most thriving communities of mosses, liverworts and ferns is that they live in wet or damp locations. The sunny sides of trees fail this test. There are of course always exceptions and some mosses are able to live in apparently very dry places but in all cases, careful study will reveal the presence of water at critical periods of the year. Velela 14:31, 20 October 2005 (UTC)

Please add this information to the article. PeepP 17:26, 21 October 2005 (UTC)

So I came to this article looking for more information on this because I was outside at work, and looked in the courtyard where there are several large stones. I noticed that moss was growing only on the north-side surfaces of these stones. The Courtyard is enclosed in all fours by tall buildings, so I don't think sunlight exposure is at work here. If you guys find more information regarding this please post. Taco325i 16:26, 7 April 2006 (UTC)

There are lots of possible reasons, including (1) people tend to sit preferentially on one side of the rocks, preventing moss from growing, (2) the rocks had moss on them when they were placed there and the moss was placed in that direction, (3) water tends to run down that side of the north side because of the slant of the rocks, and half a dozen other possibilities I could mention besides. Note that just because the buildings are tall doesn't mean that during important times of day or important times of the year that the sun doesn't preferentially hit the south side of the rocks. And of course, there's always the possibility that it's pure chance in this case. --EncycloPetey 02:44, 10 April 2006 (UTC)

I just happened to read the right section of the book "A Short History of Nearly Everything" by Bill Bryson. At the bottom of p. 427 you can find some info about that. According to him this applies to lichens and not mosses. --Emil Petkov 12:32, 6 October 2006 (UTC)

Whatever Mr Bryson has to say, the evidence is all around, certainly here in the wetter parts of northern Europe. Lichens, mosses and terrestrial coccoid green algae all visibly favour the northern sides of tree trunks. It doesn't require great science to demonstrate it, a walk in the woods is all that is required. Mt Bryson is amusing and erudite but I don't believe has made any claims to be a scientist, great or otherwise. I suggest that enjoying his text as amusing fiction but relying on competent observation and scientific method to determine the verifiable truths in biology may be the optimum balance. Velela 21:29, 6 October 2006 (UTC)

Is it really accurate to say that the northern side of things get more light? I mean, the sun is obviously 'pointed at' the equator, but it's so friggin huge that it might as well be 'overhead' no matter where you are. The idea that the northern side of the trees is 'wetter' by a significant degree sounds fishy

Why not read some ecology research? The northern side of objects in the northern hemisphere receive less light because of the curvature of the Earth. This feature of the Earth is also responsible for the seasons -- The angle of incident light varies seasonally. The sun is closer to being directly overhead (at noon) during the summer, but sits lower in the sky during winter. On a microclimate scale, it means that (on average) there is more shade on the north side of an object than on the south side. Bryophytes are known to prefer less intense and less direct light because of the problems of retaining water without a vascular system. See Bryophyte Ecology edited by Chopra and Kumra as one source with summary information about water relations in bryophytes. --EncycloPetey 01:03, 11 March 2007 (UTC)

I suggest you leave the city you have obviously been in your whole life, and enjoy nature for just a week-end. See a tree that is growing elsewhere than on a sidewalk. Come on ! How can anybody really believe that the north side of anything gets as much light as the south side ? Is the north side of your habitation as hot as the south side in summer at noon ? —The preceding unsigned comment was added by 81.56.208.127 (talk) 04:58, 22 April 2007 (UTC).

[edit] Start it simpler

Um -- could we start a little simpler? This article doesn't really answer "What is moss?" unless you know an awful lot of botany to start with. (And the story about moss being on the north side of trees is said to have helped to make many people even more lost!) Oak 17:24, 04 November 2005

I agree that this article doesn't do a good job in the introduction of clarifying what a moss is for the non-specialist. Part of the problem is that in casual English, the word moss means "green scummy thing on a rock or tree". Many times, the word is applied to a liverwort, alga, or even to some bromeliads (Spanish "moss", a flowering plant) indiscriminately. To distinguish true moss (the subject of this article) from those other plants requires a level of technical description that can be very hard to bring down to the level or the casual reader. The required terminology just doesn't have an equivalent in casual speech. -- EncycloPetey 14:13, 5 November 2005 (UTC)

[edit] Dioicous vs Dioecious

While dioecious is the correct spelling of that word (in both Commonwealth and American English), it is not the correct spelling for the word dioicous, which is another word entirely. In botany, a plant that is dioecious is a diploid sporophyte that produces either microsporangia or megasporangia, but not both on the same plant. A plant that is dioicous is a haploid gametophyte that produces either antheridia or archegonia, but not both on the same plant. So while seed plants may be either monecious or dioecious, they are all dioicous. Bryophytes produce only a single kind of sporangium, and so cannot be truly described as either monecious or dioecious. There are fundamental differences in the life cycle that necessitate a different vocabulary among bryologists. -- EncycloPetey 16:17, 6 November 2005 (UTC)

[edit] Image name is misleading

In the image at the start of the Classification section (captioned "three different types of mosses surround this tree trunk"), I can only see two species of moss. The box in the upper right shows a foliose lichen, which is a fungus-alga symbiosis. Also, the box on the left side of the image contains about half moss and half lichen. Does someone have a better image? -- EncycloPetey 16:25, 6 November 2005 (UTC)

A good source of images is always Wikimedia commons - see [Category:Bryophyta]

Velela 06:45, 7 November 2005 (UTC)

I looked, but that category of the Commons is empty. If I were in Arkansas or North Carolina, I'd just pop out and take a good picture to replace the current one. Unfortunately, the local climate is Mediterranean, which doesn't lend itself to finding good shots of mosses. -- EncycloPetey 13:20, 9 November 2005 (UTC)

You're right - sorry - no idea why that link didn't work . Try this one instead

http://commons.wikimedia.org/wiki/Category:Bryophyta.

There are hundreds of images to choose from. On a related topic, I have included a short plain man's guide to mosses at the beginning to overcome criticisms that this artcile was not suitable for non-botanists. I propose to do something similar for Liverworts and Hornworts. Any views ?

Velela 13:29, 9 November 2005 (UTC)

Since this issue covers more than one page, I'll respond on your talk page. -- EncycloPetey 13:55, 10 November 2005 (UTC)

[edit] moss uses

[edit] GA review

While this article is pretty good, unfortunately it is almost completely unsourced, and the good article criteria stresses that all material in the article must be verifiable and cited. Once everything's cited, feel free to nominate this article again! Krimpet (talk/review) 02:01, 3 April 2007 (UTC)

[edit] Ant on moss image

This image was removed becuase it was a little blurry. Yes, it's blurry, but it's the only picture on the page that demonstrates the physical scale of moss. I would love to see a better picture, but until such a picture is available, it makes more sense to retain the information conveyed by the picture than to simply delete it for being less than ideal. --EncycloPetey 03:18, 4 April 2007 (UTC)

As per your request, I've made it part of my to-do list to take a shot of moss (perhaps 2-3 types if I can find them) with a ruler beside it. -- KirinX 05:56, 4 April 2007 (UTC)

Further to that, I still don't think that the image demonstrates scale to a definitive degree anyways, as ants come in many sizes (albeit all are fairly small, but so too can that be said for mosses -- I'm certainly unaware of any large mosses), and for the fact that there are two pictures of trees featuring different types of mosses on the stump or on the trunk of the trees. It's not unreasonable to believe people would have the same ease (or difficulty) in ascertaining scale from any of the pictures, closeups not included. In all honesty, I cannot see why you are defending the removal of this picture to the degree you are. Forgive my shortsightedness. -- KirinX 06:03, 4 April 2007 (UTC)

I agree, which type of ant is it? How big is the ant? How much moss is he standing on? I can't tell from that image, it tells me nothing about moss. ^High_InBC^{(Need help? Ask me)} 13:44, 4 April 2007 (UTC)

The picture could definitely be imporoved (and should!). I disagree with the arguments about moss on the sides of trees demonstrating scale, though. Some trees may trunks less than a half a foot in diameter, while others may have trunk bases over five feet in diameter (especially in tropical regions). I would have put in a replacement image long ago, but all my good moss images are on photographic slides and I have no way to scan them currently. --EncycloPetey 21:14, 4 April 2007 (UTC)

[edit] Moss leaves and stems

Bryologists do not put quotations around the word leaf. They do not call the leaves of mosses and leafy liverworts "leaf-like appendages"; they simply call them leaves. While mosses do not have "true" leaves, they do have leaves. Leaves have evolved multiple times in multiple linages. Even "true" leaves are not homologous among all groups, since the microphylls of lycophytes, the frond of ferns, and the leaves of seed plants all evolved independently of each other. Because of this, it is meaningless to say that mosses do not have "true" leaves, as if the presence of vascular tissue is something special. Denigrating the leaves of mosses is a POV issue perpetuated by botanists who do not study mosses. --EncycloPetey (talk) 19:08, 11 January 2008 (UTC)

Only just now did I find out about your wholesale reversion of my edits. I took this opinion straight from Biology 8th ed. (Raven), specifically page 587, which says,

...The gametophytes of mosses typically consist of small, leaflike structures (not true leaves, which contain vascular tissue) arranged spirally or alternately around a stemlike axis...

This means, in retrospect, that I probably should have cited it, but nevertheless my position was not unfounded. There is a bryologist in my biology department, so I might consult him on the subject, but there are nevertheless large differences between these structures (which might deserve mention in the article).

What I'm more concerned about is this: (diploid, i.e. each chromosome exists with a partner that contains the same genetic information). This isn't terribly accurate. Two homologous chromosomes contain the same loci (in healthy individuals), but may contain different alleles. --♦♦♦Vlmastra♦♦♦ (talk) 03:37, 24 January 2008 (UTC)

No need to ask your bryologist. I have a bryophyte library here and can cite numerous sources from varied leading authors calling these structures leaves without any weasel words. Consider this quote from Crum and Anderson's Mosses of Eastern North America (one of the leading moss Floras in print, v. I p.13, description of Fontinalaceae): "leaves in 3 rows and sometimes conspicuously 3-ranked". Or from Wilf Schofield's Introductory Bryology (p12, general description of moss structure): "The gametophyte consists of an axis, usually termed a stem, and this axis bears leaves." Or from Bryophyte Ecology, edited by A. J. E. Smith (p.114, chap. on Desert Bryophytes): "It is a very general feature of arid region perennial mosses that their leaves change position markedly between the dry and imbibed states." Or from the primary literature "Phenology and Reproductive Biology of Syntrichia inermis..." by Lloyd R. Stark in The Bryologist 100(1):13-27: "It is a distinctive species, recognized by the coiled leaves when dry." Or from authors of India, Biology of Bryophytes by R. N. Chopra and P. K. Kumra (p286 on external water conduction): "In many mosses leaves are closely placed on the stem." Or from New Zealnd authors Bill and Nancy Malcolm The Forest Carpet (p.56): "In most mosses the central region of the leaf thickens into a midrib." In short, you would actually be hard pressed to find any bryological literature that did not call these structures leaves.

There are large difference between the leaves of a waterlily and the leaves of an agave. There are large differences between the leaves of a pine and the leaves of a philodendron. There are large differences between the leaves of a fern and the leaves of a club moss. There are differences between the leaves of a liverwort and the leaves of a moss. An expanded section on general moss morphology and anatomy would certainly be appropriate (and is on my list of things to do), but emphasizing the differences between one taxon and one other taxon would not be appropriate. All modern cladistic studies agree that "leaves" evolved multiple times, even among the vascular plants. So, having vascular tissue in the structure is nothing special. The leaves of ferns evolved independently of the leaves of seed plants, and both evolved independantly of the leaves of lycophytes. Even though they all have "true" leaves in the sense meant by Raven, "true" means nothing. It's merely a human label and is redundant with the fact that those groups are vascular plants.

The definition of diploid is accurate enough to explain what diploid means when it appears as a parenthetical statement glossing the word "diploid" on a page about mosses. More precision may be found by following the link. Your revision introduced the word homologous, which is why I reverted it. Defining an unusual word like diploid by using another unusual word like homologous is not good practice. --EncycloPetey (talk) 04:02, 24 January 2008 (UTC)