Talk:Fern

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Fern is included in the 2007 Wikipedia for Schools, or is a candidate for inclusion in future versions. Please maintain high quality standards, and make an extra effort to include free images, because non-free images cannot be used on the CDs.


The image is perfectly good, but there are still serious problems with the way the servers handle replacement images. I will reload this image later if it does not clear up - Marshman 04:54, 21 Feb 2004 (UTC)

I think is good add the fossil register in the article: http://www1.akira.ne.jp/~unzen/pteridophyta.jpg How I can do the upload? - Aurélio A. Heckert 12:42, 15 Jan 2005

Contents

[edit] Phylogenetic relationships

A classification of the ferns based on DNA analysis (see Hasebe et. al."Fern Phylogeny based on rbcL Nucleotide Sequences", American Fern Journal 85(4) (1995) 134-181) might look somewhat like the following:

Families Hymenophyllopsidaceae and Lophosoriaceae were not sequenced in the study, and are placed above based on morphogenic relationships identified by others. The study found families Dennstaedtiaceae, Pteridaceae, and Dryopteridaceae to be polyphyletic. The families in Order Polypodiales could probably be grouped into monophyletic suborders. Tom Radulovich 07:04, 19 May 2004 (UTC)

[edit] Fly repellant

I live in Italy and my Italian neighbours have taken to hanging fern outside and inside their houses. They tell me it is acts as a fly repellant. Can anyone enlighten me on their claims?

Cheers

Phil

[edit] Classification, definitions...

Where's the classification in the pteridophyte entry from? It's not similar to anything being used in recent floristic works on pteridophytes such as the treatment in the Flora of North America or Pteridophytes of Mexico, and looks to me like there's a lot of unnecessary and confusing splitting at the order and family levels. I'd suggest that a conservative classification based on taxa that are recognized in floristic works would be much more useful... if we want to base things on recent gene trees we can give a different classification for every paper published, which accomplishes nothing.

FWIW, I've started a bit of modification on the families... I'm wondering if anyone has thoughts on order/subclass type stuff; the large amount of higher-level division in the currently-listed classification only makes sense given a high level of family-level division (e.g., otherwise most of the orders are monotypic), which (IMO) doesn't make sense given the current lack of well-supported groups at the family level. But I haven't been keeping track of recent papers enough to know what order/subclass divisions other people are using. Paalexan 22:48, 18 November 2005 (UTC)
There is the one at the top of this page - Marshman 02:05, 19 November 2005 (UTC)
I know... but that's 1995. I'm assuming more's happened since then. I guess I'll have to go wander the literature... Paalexan 19:13, 20 November 2005 (UTC)
Looks like there aren't any more recent analyses that improve on Hasebe et al., so far as I can tell. Also worth mentioning that Hasebe et al. don't worry at all about higher-level nomenclature and simply list previously used family names rather than revising anything at the family level. The result is that a number of different ordinal and familial classifications are consistent with their analyses, and since it's only a single-gene phylogeny with poor support for a lot of the nodes, it seems unwise to draw general conclusions from it... Paalexan 21:30, 20 November 2005 (UTC)

I'm also baffled by this:

"Two related groups of plants, commonly known as ferns, are actually more distantly related to the main group of "true" ferns. These are the whisk ferns (Psilophyta) and the adders-tongues, moonworts, and grape-ferns (Ophioglossophyta). The Ophioglossophytes were formerly considered true ferns and grouped in the Family Ophioglossaceae, but were subsequently found to be more distantly related."

I'm not aware of any recent publications that show Ophioglossaceae and Psilotaceae as anything other than ferns. The view that they were separate is the older view that has been contradicted by more recent genetic evidence, not the other way around!

The Psilotaceae is regarded as a fern ally family (Palmer, 2003). Not sure where that fits in - Marshman
? Which paper is this? I'm also not sure what you're meaning by "fern ally"; the term is often used to refer to the equisetophytes and lycophytes, but doesn't have too explicit a meaning... - Patrick Alexander
Palmer, Daniel D. 2003. Hawai`i's Ferns and Fern Allies. Palmer is student of Herb Wagner. He admits that fern taxonmy is complex and controversial and far from settled. But he defines fern allies as: "distinct evolutionary lines with no close affinities and....only distantly related to ferns." Certainly that fits the Psilotaceae. He includes the Ophiglossaceae as a fern family - Marshman 23:00, 15 November 2005 (UTC)
Ah. I'd been thinking you meant J.D. Palmer, who's done a couple of papers involving phylogeny of all plants. I'm not sure why D.D. Palmer defines things as he does in that book (which I have, BTW, and which is excellent for IDing Hawaiian ferns). Genetic phylogenies I'm aware of all place Psilotaceae and Ophioglossaceae as sister taxa basal to the rest of the ferns. Calling the two of them together a separate division is compatible with phylogeny, but just seems like pointless splitting to me. Paalexan 19:21, 16 November 2005 (UTC)
Then you can see he does avoid committing to a higher taxonomy (nothing above the family). Yes, an excellent book for taxonomy. - Marshman

There are also a bunch of problems with definitions of "fern", etc. E.g., all plants reproduce by spores and have alternation of generations, so introducing these as distinguishing characteristics of ferns is misleading. Also, absence of seeds only gets you halfway there, since lycophytes and equisetophytes also lack seeds. And then rhizoids are referred to as stems, which is simply incorrect. - Patrick Alexander

Disagree with "all plants have alternations of generations". Aside from the fact that that terminolgy is not much used anymore (as it is incorrect), by some definitions the "A of g" refers to independent stages. Seeds - right, but an important distinction none-the-less. Rhizoids on the prothallus s/b root-like structures. - Marshman
As far as I'm concerned, alternation of generations just refers to both the diploid and haploid stages being multicellular. Either way, the term isn't particularly relevant and the important thing is that all plants have diploid sporophyte and haploid gametophyte stages that are multicellular, and the differences between them are in the relative sizes, forms, and trophic abilities of the gametophytes and sporophytes and in level of differentiation within gametophytes (i.e., pollen & ovules vs. bisexual gametophytes). Worth mentioning in that regard that Marsileales shares highly-reduced, short-lived male and female gametophytes with the seed plants... Paalexan 19:21, 16 November 2005 (UTC)
Very interesting. I think there is more than one concept of "alternation" out there, and I lean more towards the "free-living" distinction, but all types intergrade and I like the way you put it. Can I move that over to the article alternation of generation? - Marshman 20:16, 16 November 2005 (UTC)
Feel free to move things over to the alternation of generations article. 128.123.94.172 21:38, 16 November 2005 (UTC)
You can certainlty start making corrections/changes. If sources are not given, I'd suggest adding some. Usually a page like this grows by inputs from lots of people, so you may be questioned, but charge ahead and be ready to support your changes. By the way, the best way to start any serious editing is by setting up an account at Wikipedia. It is very easy - Marshman 21:16, 15 November 2005 (UTC)
Yeah, I've set up an account. I just figured it might be better to start by posting stuff on here rather than do major changes and then have everything changed back if there're people committed to the current setup. - Patrick Alexander
Good strategy. You can sign your replies with a row of 4 tildes ~~~~ and your screen name at the date/time stamp will be appended automatically - Marshman
Well, now I've messed with things a little. I might do more later, like adding pages with general definitions of sporophyll & trophophyll, discussion of variation in them between plant groups, etc... Thanks for letting me know about the 4-tilde thing, seems useful. Paalexan 19:21, 16 November 2005 (UTC)
Excellent rewrite. Clarifies things tremendously. I note you deleted the term "prothallus". Is it no longer used?
Be a bit cautious adding pages (articles) that are nothing more than definitions. One rule around here is "Wikipedia is not a dictionary"; Wiktionary is, however. Best to incorporate definitions of scientific terms within an article with a broader context (need not be one as general as "ferns" of course). - Marshman 20:16, 16 November 2005 (UTC)
Regarding "prothallus"--AFAIK it's synonymous (or nearly enough so that it doesn't really matter) with just "thallus". I noticed both were used in the article without distinction, so just simplified things by changing it to only using one. And, yeah, if I add pages for sporophyll & so forth it'd be with the idea of saying something about the kind of important variation in them, how that relates to major plant groups, etc., rather than just a definition. 128.123.94.172 21:38, 16 November 2005 (UTC)
And when you log in (don't forget; that is why the tildes have only an IP address) check the "remember me" box. Most of the time, you will be recognized and not need to log in each session - Marshman 21:46, 16 November 2005 (UTC)

My books use 'prothallus' for these; two give different definitions in their glossaries:
Prothallus: (1) The gametophyte generation of ferns and other cryptogams, a delicate liverwort-like structure bearing the antheridia and archegonia on its lower surface and providing a site for the fusion of gametes and development of the sporophytes generation. (2) A small plate of tissue derived from a spore and bearing male and female reproductive structures.
Thallus: (1) An undifferentiated vegetative growth. (2) A plant body not differentiated into leaf, stem and root.
I think we'd do better to use 'prothallus'? - MPF 10:02, 17 November 2005 (UTC)

Yes; I was going to add it in since it is a word encountered in books, etc. so its complete removal could leave some reasders wondering. Can we put those defs up on Wiktionary ? Suitably reworded to avoid copyright violations - Marshman 17:52, 17 November 2005 (UTC)
Prothallus it is, then. By the definition "2" for "Thallus" (which is the definition of the word I'm familiar with), the gametophytes of most ferns are thalli (as well as prothalli!); but "prothallus" seems to be more often used for fern gametophytes (whereas, for whatever reason, "thallus" seems to be used more often for liverworts, though they don't differ from fern gametophytes in ways that are, AFAIK, relevant to the definitions). Paalexan 20:48, 17 November 2005 (UTC)

[edit] vegetative propagation

when a ferns' rhizomes spread, can they grow a new independent fern? Also, we could use a picture of the prothallus Lotusduck 20:34, 15 December 2005 (UTC)

Yes, a property that is held by a majority of plants as most have open growth. Any plant that roots as it spreads or can be chopped apart and have the parts root can be separated into "independent" plants, but that is nothing special or unusual in the plant kingdom. Lacking a centralized nervous system, the idea of "independent" is perhaps the hang-up - Marshman 20:50, 15 December 2005 (UTC)

I get the impression that ferns are very poor outcrossers. Each prothallus must be wet enough to be fertilized by motile sperm, and if the prothallus is monoecious, then it just self fertilizes almost every time. If it's diecious, then I can't imagine it getting fertilized very often at all. It's kind of hard for me to wrap my head around this prothallus thing, since most archegonium and antheridium are well positioned for transport of genetic material, and the prothallus is on the ground and needs water, and will most probably self. Because of all this weirdness, I rather think there should be a wikipedia article on the prothallus, except at the moment I am too confused to start it.

Maybe later I will not be so. Lotusduck 14:19, 16 December 2005 (UTC)

Well, there certainly are a number of interspecific crosses reported for ferns, so something is going on. Also, because the spore allows for the potential production and distribution of millions of prothalli, in environmentally friemndly locations the prothalli are likely to be gill to tooth (very crowded), encouraging lots of exchange movement of motile sperm - Marshman 18:46, 16 December 2005 (UTC)

wow

[edit] Classification, revisited

Still no reference, source or citation in the article for the classification scheme being followed for ferns? All classification schemes are opinions, and fern classifications even more so than most. Despite recent molecular advances and clarifications, fern taxonomy is still a horrendous mess and you would be hard-pressed to find two pteridologists who agree on any one classification. This classification presented here is somebody's opinion, i.e., POV, so whose? MrDarwin 19:08, 24 August 2006 (UTC)

I think a modern approach is the followed by Judd et al. (2002. Plant systematics: a phylogenetic approach, Second Edition.Sinauer Axxoc, USA.), availed by Pryer et al. in the 2004 paper ("Phylogeny and evolution of ferns (monilophytes) with a focus on the early leptosporangiate divergences." American Journal of Botany 91:1582-1598). 200.43.74.219 21:50, 17 October 2006 (UTC)
The recent classification of Smith et al. 2006 is now references in the article, but as far as I can tell nobody has updated the unreferenced classification scheme presented in the article to reflect it--I hope somebody will eventually have the time to get around to it. MrDarwin 20:34, 28 December 2006 (UTC)
I've just made a major edit to the classification section to reflect the proposed classification of Smith et al. 2006. While quite new and a major departure from some other classifications, in many respects this is the fern version of the Angiosperm Phylogeny Group classification, as it is authored by several respected pteridologists and is based on numerous molecular systematic studies supplemented by morphological data. Most importantly, it is a referenced and verifiable classification linked to a publshed paper that can be consulted for further information, unlike the rather mysterious one that was used previously. The classification section of this article still needs major work, but I hope this will provide a framework, and encourage other editors to go to the various fern articles and update their classifications. MrDarwin 01:59, 29 December 2006 (UTC)
One additional note: the Smith et al. 2006 classification does not recognize any named taxa above the rank of class, so it may be tricky to accommodate in taxoboxes. For the most part I've avoided editing taxoboxes, especially at the higher ranks--not my cup of tea, so I'll leave that to others. But in looking through the various fern and "pteridophyte" articles and taxoboxes I've found quite a bit of inconsistency in classification, with the text and taxoboxes in numerous articles contradicting each other. MrDarwin 14:08, 29 December 2006 (UTC)

[edit] Images?

Just posted an image of fern spores, but I don't really know how to identify this fern. Help! Anca 07:09, 29 August 2006 (UTC)

Post a query on the WP:PLANTS talk page. Some sort of basic description of the whole plant would help, e.g. total height of the plant, length of the fronds, etc - MPF 08:58, 26 October 2006 (UTC)

On images for the whole page, it seems to be getting used as a dumping ground for photos of unidentified ferns. There are now numerous photos on commons of identified species; I propose to remove all the un-named photos, and replace them with a selection of named species showing more of the diversity of structure of different ferns - MPF 08:58, 26 October 2006 (UTC)

Totally agree. What would be more useful would be some photos of typical life stages - i.e. close up of a sorus, prothallus etc. Mrs Trellis 09:53, 26 October 2006 (UTC)
Nice idea, if we have any pics of them! I'll take a browse through commons to see what there is - MPF 13:13, 26 October 2006 (UTC)
There is one here that might be possible. Mrs Trellis 14:09, 26 October 2006 (UTC)
Prothallus
Prothallus

[edit] Fern Life Cycle

It would be useful to have a section on the life cycles of ferns in this article - does anyone agree? Wriggles1 23:06, 10 December 2006 (UTC)

[edit] ferns in Spain

Greetings fern lovers, Am doing meatball surgery on a translation Forests of the Iberian Peninsula/Translation and have been surprised that no mention seems to be made in the original article of ferns in Spain. I know for a fact that they exist, at least in Asturias, a damp part of the north of the peninsula, and I'm pretty sure I read somewhere that since the 80s they have been a protected species in this country, together with moss. Can anyone help me out, and if relevant, add the reference to the fern article. Thanx. --Technopat 23:30, 10 February 2007 (UTC)

There are dozens of fern species in the Iberian Peninsula, including rock ferns in the mountains, even in semi-arid areas. I have a field guide to ferns of Spain and Portugal; I'll try to find it. jaknouse 23:47, 13 July 2007 (UTC)

Greetings, Jaknouse. Thanx. Regs.--Technopat 22:38, 5 August 2007 (UTC)
"Blätter des Mann=Waldfarn" Nature print by Alois Auer
"Blätter des Mann=Waldfarn"

Nature print by Alois Auer

[edit] References

Should references not be noted in the Text? Osborne 12:28, 15 February 2007 (UTC)

[edit] Jurassic Park fern

I cannot find an article for Serenna Veriformans a fern mentioned in Jurassic Park, can any one provide some info, please. 71.81.37.185 —Preceding comment was added at 01:54, 6 November 2007 (UTC)

It's not listed in any of the major paleobotanical texts. It may have been invented by Crichton for his novel. --EncycloPetey 02:23, 6 November 2007 (UTC)

Crichton Rules!!!! —Preceding unsigned comment added by Assassins creed1 (talk • contribs) 03:10, 6 May 2008 (UTC)

[edit] Haploid

  1. A sporophyte (diploid) phase produces haploid spores by meiosis;
  2. A spore grows by cell division into a gametophyte, which typically consists of a photosynthetic prothallus
  3. The gametophyte produces gametes (often both sperm and eggs on the same prothallus) by mitosis

(I quote, as a lay ignoramus)

But, but.... the spores are thus haploid but grow by cell division into a gametophyte which is surely diploid if it is to produce two gamete types???? —Preceding unsigned comment added by 81.152.7.211 (talk) 09:15, 22 May 2008 (UTC)

No. All gametophytes of plants are haploid (under normal conditions). Gametes are not produced by meoisis in plants. --EncycloPetey (talk) 13:32, 22 May 2008 (UTC)