# Swamp find



## jaidexl (Jan 20, 2007)

I thought this was fissidens when I grabbed it, looks like a plant to me. 
Found at 26°35'25.7"N 81°48'33.8"W. It forms a mat as it intertwines and clings to itself but I have it spread out here.

Test tube for scale...


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## miremonster (Mar 26, 2006)

Yes, that looks like Fissidens fontanus. I wrote a while ago in another thread that there's a group of 5 Fissidens species incl. fontanus, called the subgenus Octodiceras. All fully aquatic and looking very similar to each other. From that group F. fontanus and F. hallianus occur in North America.
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250075574
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250075573

According to Flora of North America both species occur in Florida. Differentiation by some microscopic characters of the leaves and position of the spore capsules (if present; F. hallianus: on the top of the stems, F. fontanus: in the leaf axils).
Key (see further below): http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=112827&key_no=2


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## jaidexl (Jan 20, 2007)

Huh, no kidding... the many faces of Fissidens. I always find it out of water and more robust, this has not changed on my tank yet so I started to second guess myself. The tips are so delicate and thin it reminds me of star grass. Thanks for the ID


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## miremonster (Mar 26, 2006)

I haven't IDed it yet! I'm sure with subgenus Octodiceras only, and your Fissidens has to be checked if it's Fissidens fontanus or F. hallianus. If it turns out as the latter, it would be new to the aquarium hobby (as well as the rest of the subgenus Octodiceras except F. fontanus).

The more robust one that you've found emersed may be another Fissidens species (not subgenus Octodiceras).


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## miremonster (Mar 26, 2006)

Again:
the ID could be clarified by looking at the leaf tips with a microscope.
Fissidens fontanus: the leaf midrib (costa) ends 15 - 35 cells before the leaf apex.
F. hallianus: 5 - 15 cells.
Source: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=112827&key_no=2

Here are photos of Fissidens hallianus, it looks more compact in the pics, but that's likely not a distinguishing character. The short distance (few cells) between end of costa and leaf tip is visible in the 2nd pic:
http://plantdb.biology.duke.edu:8080/BryoImages/Fissidens_hallianus/ipage00001.htm
http://plantdb.biology.duke.edu:8080/BryoImages/Fissidens_hallianus/ipage00004.htm

If the swamp find is F. fontanus: surely it would be interesting to find also F. hallianus and to try it in a tank.

Also the San Marcos fissidens wasn't really IDed: http://www.aquaticplantcentral.com/forumapc/plant-id/75881-san-marcos-fissdens.html


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